I've been using one for years in a stored car, every winter. It's quite happily extracting a litre every few days and the full turn-off switch works fine. However, don't forget to empty it every so often, as when a big freeze occurs, the ice formed in the catch tank will crack it wide open. Of course, the availability of spares for these is non-existent. As you found, the fan is nothing more than a cheap generic PC component - I replaced the OEM one after a year due to noisy bearings. The replacement, a decent quality Papst, has lasted for years. One thing I found was the unit, more importantly, the power supply brick, wasn't immune to flood damage, and that killed it. It lives on though; now being powered by an ATX PSU, the Peltier modules just chuntering away like they'll never give up. In fact, I was so impressed by how it did its job, when it wasn't being nearly killed by weather and bad luck, I bought another one recently, to go into another car. These things are ok for that size of volume, but for a room, forget it.
I don't want to break it but when did that stop me before. Lol. I love the fact you are part curious kid, knowledgeable engineer and intelligent comedian all in one.
love your vodcasts Clive they are always so informative. they tell me everything that I need to know about how a device works and therefore how to check it is functioning correctly and repair it if it is not
compressor (phase-change) cooling is so more efficient then these peltier fridges and dehumidifiers coming out. I have a compressor mini fridge that draws 45 watts (closer to 500w for a few seconds on startup) and can freeze everything solid, but have a relitive that has a peltier based mini-fridge and is always complaining that the internal temp is around 50 degrees, I put my kill-a-watt on it and it was drawing 200w, not to mention it'll never reach temperature and kick off unlike a compressor version.
The peltier fridges are terrible. very inefficient, but cheap to make and sell to people without actually mentioning that the running costs will be so massive.
They're really meant to be used for small, battery powered chillers. Or in small places like a gun vault or safe. Something to bring camping or on a picnic to keep things cold for a few hours. If you don't need it to be portable, phase change is absolutely the best option.
You are hilarious! "It was certainly worth taking to bits" & "It's brand new but that's never stopped me before"! Thank you for the very educational video & the smiles.😁
Ahh good work, Clive! I've got one of these in an alcove for some defense while a neighbour's overflow pipe was keeping the outside wall wet. Thanks to your efforts here, I now won't have to risk busting it with my curiosity. Big Clive Public Information Service. My next coffee dedicated to you, sir.
I used to use them way back in the late 90s, around the AMD K6 or Pentium III era. They worked very well unless the fan on your heat sink died, then they were capable of some extreme temps on the hot side and would typically burn out.
hey I got one of these and want to use it in my fridge i dont want a dessicant dehumidifier as it adds more heat what can i do to make it stop freezing up. I have a controller i can use to control the on/off and humidity %
If the power supply output allows, you might be able to replace the peltier device with higher wattage one. If you use bigger one you may confront freezing problems instead of condensation, for that reason as you know, you cant go too far on that. You can make your own. Increasing heat sink area may solve freezing problem because it would dissipate the sub freezing cold which I know you know it very well.
I have a slightly larger one of these in a walk in wardrobe with an outside wall. we suffered much condensation mould. since using it we have no mould. they are good for small spaces like wardrobes.
Hi Clive, thanks for this teardown video. I've always wanted a small dehumidifier for a tiny room and had looked into the peltier-based models, but found $35USD+ way too expensive for what essentially is a peltier and a few heatsinks. Now that I know how these things work, I can use a few peltiers I have and some spare heatsinks to recreate this device for only the cost of my time. Thanks again!
+Patty Two Wheels A recent test showed that the peltier unit was only about 20% as efficient as the desiccant drum unit. So the initial cost of the small unit would soon be outweighed by the running costs.
The point of the vid is this design is bad even when optimized it’s just a very ineffective way if you’re looking to actually draw a decent amount of water per day. This inherent limitation and slope of increasing inefficiency as the area around it comes to temp. His whole point is this would be completely ineffective in any practical sense. So I don’t suggest you waste your parts and time this way, Peltier modules as a whole are just super inefficient even with the high power units it would be terrible at this practically for condensation uses even with high power consumption. The math has been done and even with the most efficient end best units we can make it would still be wildly ineffective. Technically they work but there exist much better ways as even refrigeration with gasses abs compression is more efficient generally. Hence the self filling water bottle thing or the “water seer” devices and anything similar can never work and would barely provide a few sips of water a day. Sorry but they haven’t found a miracle that solves the water crisis so simply and easily. Keep in mind the Waterseer was a straight up scam and basically so is any similar fonts self filling bottle and they absolutely know it never word. And high school student could do the math to show what would be produced with the power used and the modules we can make and quickly find the idea as laughable and only works technically ever so slightly in (theory usually lol) as being a step away from free energy . Physics says so. Maybe try some of the other project uses for your spare unit and make something more useful and effective like a fridge. And you could do solar but the required panel would defeat the purpose and raise size and cost vastly. Wall power is cheap and likely available to you.
Of course it adds about 30W of heat to the space it's operating in, which lowers the humidity by raising the temperature. When I worked with my dad in a resort, there was a 100W light bulb in the outdoor box that contained the PA system, just to keep it a little warmer inside and prevent condensation that would mess up the electronics. So in a confined space like a linen closet, this peltier unit might be as effective as a 40W bulb.
Until a few days ago, I haven't heard of the Peltier effect. I got a mini dehumidifier for my bedroom. It does help. Maybe not as well as a dehumidifier that has a compressor.
I wouldn't have thought about a Peltier dehumidifier. I'm so used to the old fashioned refrigerated ones that it never occurred to me that that was an option. Nice find Clive. You dissect some of the neatest little gizmos.
It's really inefficient compared to the refrigeration and newer desiccant drum style dehumidifiers. More of a novelty than a useful device unless you have a small space needing kept dry with just a 12V supply. (Like a remote cabin with a solar panel.)
I don't feel so bad about my effort to make one now. I re-purposed a mini fridge to act as a dehumidifier and it was able to extract about a teaspoon an hour. The mains power one I bought takes out way more water.
The module is very cheap, you can get what I think is the exact same unit on ebay for $0.99. This is a 4 amp model, you can get a 15 amp version for $5.00.
My original intention for this humidifier was to use it for plants that require high moisture levels. After using it in my room, ua-cam.com/users/postUgkxtD9aJ2m6GU-X1IChQxjn9l31K1A7Kpwj however, I think that's where it is going to stay in the fall and winter season at least. The increased humidity in my room made the room warmer and more comfortable. I had first ran the humidifier for 4 hours with the timer setting for it. After the first hour, I checked my room and can feel the difference. When the full 4 hours was up, I checked again and noticed that the humidifier was shut off as it is suppose to. The moisture level never seem to get passed 56/57%. I then let it run until all the water is used up, which it wasn't all used up. There are still some left in the base that you are not suppose to add water to. I filled up the water tank all the way again, being careful when removing it from the base. Some left over water may spill out. After putting it back on and setting the unit to auto, I let it operate. It didn't stop running, rather I don't know if it did at any point since I didn't check it regularly, for 24 hours after which the water in the tank ran out. The moisture reading never passed 56/57%, which may be a good thing for me. Being situated right next to my bed, the noise was not very noticeable with the occasional water gurgle from time to time as the unit ran.
i'm researching in regard to extracting water from air using desiccant surface. if a dehumidifier like this modifies in design it can produce considerable amount of water. thank you for your video very useful
If you reverse the polarity on the peltier junction, It won't just swap the hot and cold sides. It will in fact transport heat in the opposite direction but at a drastically reduced rate. They only really work in one way and therefore they must always be supplied as specified.
You are correct, if you change the heat sinks with larger sized ones in the cold side then you can eliminate that issue. Considering people would likely be hacking these devices for other purposes if they're changing polarity anyways, it's a simple matter to do. The peltier element itself works just as efficiently in either polarity, it's only the heatsinks that make a difference.
I got one of these its great works really well it lives in my little workshop I need to change its tank about once every 3 days. Yes it does make a slight 'snuffling' noise when its running but I find it nice
i like your idea about running off a solar panel. I was thinking the same thing as im aware that these peltier devices are hugely inefficent from an energy perpective. I have a small area at the back of my garage of around 5sq m floor space that is insulated in which i keep my lathe and miller . I think im going to get one to stop flash rusting of the surfaces ( and add around 30watts of heat to the room)
Hey, hi from AU! Somehow missed this video, and nice to watch the teardown, tell you what these little things are great for - I have one in a small 60x60x50cm(ish) file cabinet/drawer I sealed and insulated and keep printer supplies in - where I am averages 75%rh and goes to 85%-90% quite regularly, this thing keeps 35C 35%rh almost all year round and produces a litre of water every six to eight weeks, excellent for old style lead acid batteries and I also use it to keep solder sponges wet and give the rest away to people that still do ironing... It's been going for almost three years now and reminds me why we like solid state devices...
lol no isolation between the heatsinks? and joined by a metal screw? and it actually have thermal paste that goes from one side to the other (@9:00). i think, maybe, that's not very optimal.
Thanks for the video, helped me get going on repairing. I have two of these that stopped working after a year. I’ve replaced the Peltier modules and they’re working well again. I wondered what makes them fail, maybe they were clogged with dust and too hot. Peltier spec. says max 60’C. The Peltier modules on eBay are 40 mm sq, bigger than the originals, but doesn’t seem to matter. Various people have said that the hot heatsink is touching the air on the cold side, I’ve put foam there. Even worse, one of mine had a 50 mm * 2 mm gap allowing hot air into the cold side. Foam in there now. The gap is where the Peltier+heatsinks module does not quite fill the hole in in its plastic housing.
I also have one of these, it runs on only 9V. It has some additional component near the heat sinks, I guess it must be some kind of thermal switch (that either cuts out when the thing heats up too much or maybe when it would be on the verge of freezing). Because the fan is still rated at 12V, I added a ‘turbo’ switch with a booster circuit that brings it at full speed. Even then, performance is still very poor, although it helps a bit to get the moisture out of a poorly ventilated bathroom. But my big compressor-based dehumidifier pulls about 20 times the amount of moisture out of the air per Watt.
Alexander Thomas I've used a 'proper' dehumidifier to dry our washing indoors, and the amount of water it removed from the environment, even with no washing behind dried is impressive. Easily enough for two people to drink in case of emergencies wth a generator.
I have to say I was very impressed with the one I bought to get all the dampness out of my car. 600ml over the Xmas period in temperatures below freezing. For the price it did a fantastic job, how else to you get the inside of your car dry in winter. Clive, thanks for the breakdown.
I take it you must have run an external power supply to it? One of the applications where this thing would really work well is in a remote caravan with its own solar panel so that when there was enough sunshine the unit would trundle up and start extracting moisture from the interior and draining it to outside.
A bit late But, When you get close to the end of your journey turn off the heating in your car, open a window and let all the heat out of your car so the windows, seats etc, are the same temp as out side so condensation cannot build up with the heat difference, also when it's snowing out side try not to get snow inside your car of your shoes, get some rubber collector mats for your car, the type that have a grid cell pattern on them to collect the water off your shoes then you can just tip the collected water out of the car. always worked for me and still do it to this day.
Now they changed for 9V adapter, possibly lower voltage for more longevity. Just acquired the same, fills the whole bucket in 1.5 days in my 80% room humidity here, despite that it's not able to lower it as unit is too small for room size I suspect.
Just did some quick maths on this one. The latent heat of evaporation of water is around the 100,000 joules per kilo mark. I think it's actually about 118,000 but 100,000 makes the maths easy. If your kit cools to the tune of 33W then it will take about hour to condense 1kg of water IF it's running at near 100% efficiency. The problem is that the hot bit and the cold bit are too close together so it is working at I would guess 10% efficiency at most.
Why the air is not pulled in from the hot side to the cold, so the temperature difference is greater and the effect would be more efficient? It is logical - just there must be additional air holes behind where the fan is and the fan should pull the air in. Then the air will go hot and then go to the cold side and then exit from the front air holes (not the back ones). And why the cold radiator is smaller then the hot one?
TES1-12704 TES (Thermo Electric Stack) TES1 (one stage peltier) 127 (number of thermoelectric pairs 04 (max current 4amps) This applies to almost all thermoelectric modules TEC or TES is meant for cooling/ heating And TEG is meant for power generation Number afterwards marks how many stages there are TES1 is most common but you can use TES2 to get slightly higher temperature difference it's basically two modules stacked ontop of each other tho one on colder side is usually 1/4 the power due to efficiency of these modules so you sacrafice efficiency. Numbers after the "-" mark number of couples usually only first three and last two numbers mark the current.
Thanks for the video, I was looking for a mini dehumidifier for 3-D printing, and was looking at them hoping there was a big Clive teardown so I could see what was inside
If it's for filament storage, I use a large storage box with foam tape round the lid as a seal and a silica gel desiccant block with integrated heater for drying itself out when needed.
This little dehumidifiers works for what is intended to be used, it will not replace a compressor style dehumidifier, but for small spaces like small RV trailers, it will work perfectly. a piece of foam around the peltier will help the cooling and heat effect.
We had a 'mini cooler' at work until some bright spark switched it from cold to hot while still turned on. A loud bang and flash was emitted and muggins here was asked if i could fix it. took it home, the 'hot/cold' switch simply reversed polarity of peltier and had shorted in the middle, melting on/off switch and hot/cold switch into one blob of plastic, and a very charred circuit under them. I took it all apart, sandwiched peltier between original heatsink and a cpu heatsink, fans on both sides, wired it to 12v cpu header on a spare pc power supply rated over 400w. Fans came on and one side gets lovely and cold and the back gets barely warm given its massive heatsink lol. it now sits in a round cliplock container next to my bed waiting for those ugly sweaty long summer nights blowing a chilly cold breeze across my face :D Instant cheap air con, yay !!
I've been using these for like. 7 years... I leave it in a cupboard I keep my. Guitars.... For where I live, SEA, I can keep humidity at 60 percent while outside hovers around 75 to 85 percent... Not bad... they are robust and still works after 7byears, However the adapter have given up on me twice. I think that's because the temperature of the cabinet sometimes exceeds 32 deg celcius, adapter overheats
Those are great !!! I bought 3 dozen of them. Still haven't found a personal use for them, though. Maybe around my boiler and drained outdoors will keep the rust down. Now to buy large heat sinks. Note to self: when using several in one gadget, it's probably best to leave decent air gaps between them.
If you ask me, the cooling heatsink doesn't look as big as it could be, and neither is the airflow optimised properly. It looks like a half-baked design, to be honest. You might dramatically improve the performance (proportionally, that is) by slapping on a much bigger cooling heatsink and improving the flow so that the incoming air has to go through the heatsink from top to bottom (or bottom to top), and making sure the outgoing air doesn't interfere with the incoming air.
The size of the cooling heatsink is probably deliberately small to increase the temperature differential between it and the incoming air. the airflow does run down the channels of the heatsink before passing round the back to the hot side. There's a very good chance this IS the actual optimised design, but it's just very inefficient by its nature.
bigclivedotcom Does the air flow from cold side to hot side? The other way preheated air should gain higher temperature difference in cold side and better efficiency.
Cmazy That would make it extract even less water than it does already! The rh would drop due to the pre-heating, and the cooling side would then just take it back to the original rh and temperature, probably getting nowhere near the dew point.
+bigclivedotcom It doesn't look as though there's adequate air flow through the cold heatsink. It should be pushing as well as pulling. Also, what was the exhaust air temperature? A dehumidifier should be temperature-neutral as far as possible. The peltier seems a bit underpowered as well. The part number 12704 means 127 thermocouple elements and 4 amps design current. But these things are very sensitive to supply voltage. If it's running on 12 volts, it will barely work at all. At 15 volts, there will be a huge difference in efficiency.
He said "from cold to hot" and that would increase the performance a lot, thats how all (real) dehumidifyers work. That way a lot less energy is wasted to cool down air when u actually just want to put energy into condensing water, as the cold air cooles the hot side it makes the cold side even colder. So it basically regenerates (some of) the energy put into cooling the air.
I have often wondered if a Peliter device would be a very good to use to make distilled water. The hot side could be used to evaporate water and the cold side could be used to re-condense it. This should result in a very efficient system. The losses in the Peltier are associated with the devices resistance. By stacking, the necessary temperature difference could be maintained. I have seen such devices used in cabinet rack cooling for telecoms and computer equipment. The advantage of such a system is that the electronics can be sealed from the outside environment, allowing the humidity within the rack to be limited with silica gel packs.
I have had 6 or 7 of these around, bought in batches of 2 or 3, and two a little larger ones. I always knew they won't be the "best thing ever", but it was mainly for space reasons that we got the small peltier ones (e. g. outside wall corner in parent's basement and bathroom, in corners on shelves i my basement), but I did not expect them to perform that bad. After 2 summers of use all the fans are rattling like crazy and all but two of the power supplied died due to failed caps, just what you expected in the description. They were just barely doing their job. Their main effect of getting the air drier is actually just heating it so relative humidity drops. Perltiers are horribly inefficient. If I remember correctly it was something like for every degree the cold side gets colder, the hot side rises by 10. In our basement we now installed some 125mm air ducts from room to room with two fans, so the air is pumped through all rooms in a circle. In one of the rooms there's a compressor dehumidifier (around 300W). It replaced two of the bigger and 4 of the smaller peltier dehumidifiers. This single device is enough to keep all the basement rooms around 65% rH, even in the problematic corners and after days and weeks of 30°C+ weather. So in essence: you're much better off getting an old fridge and leaving it running with the door open than to buy those crappy peltier things.
Its' interesting that the old big clunky fridge-style dehumidifiers seem to go much further and freeze the water and then cycle to melt that into the bucket rather than just relying on just condensing based on reduced capacity.
Sounds like inefficient operation, wonder if the customers prefered it because it seemed more powerful or something... or if the thermostat just wasn't very precise. I once had to look after a computer room that was cooled by a window mounted A/C unit (we don't have these very often in the UK) when it was working properly it dripped water onto the flue of the pizza restraunt downstairs and put it's boiler out. when it wasn't working properly (usually because a colleague had mucked about with the thermostat) you got ice climbing out through the front grill
It is impossible to choose one correct quantity of air flow and coil temperature for every condition so they designed them to work that way when working in colder conditions.
these are quite handy for drying shoes and such. that's what I use them for at least. in the humid summer months they can bring out about a tank worth a day which is not bad for it's size, but yeah if you need a real dehumidifier you should get one.
12704, about 4 amper. That easy to over heat. The reason why cheap dehumidifiers using small amper are to get fast sublimation. But it's forcing the so much.
I have one of these, and i am hoping you might be able to tell me why it stopped working. i turned it off for a few days and now when i turn it on both the power and full lights blink and nothing else happens. the water tray is definitely pushed in. thanks
Thanks a lot! I bought one of these in the begining of the year, but haven't used for some months. When I turned it on, it started a strong noise. By seeing your video I imagined that the problem was in the cooler. So I opened it, cleaned everything, put some new lub in the cooler and ... it worked! :)
hey but how does air from hot part pass to the cold part. the peltier are stuck together. so how does 12v fan passes the air from hot part to cold part
There is one thing they forgot in the design..... I have exactly the same dehumidifier running in my shed, but when the temperature in the shed goes below about 8°C the cold side heatsink becomes one big lump of ice ! So I added a 10° clixon to turn it off.... (also added a drain hose so I don't have to empty it manually 😄)
I have the exact one in my towel closet. It was going alright for about a year then he bearings went on the fan. Just replaced it with a Noctua one. Next I was going to see if I could make it battery powered so I can out it in closets without a power point
Without a mention of the humidity you exposed it to, and the temperature and square footage of the space, and the exact time allotted for the device to run, there is no way to determine whether the small amount of water you found is reasonable for such a small device or not. When attempting to review a product try to think of all the relevant parameters to pass on as without them you could be misleading people with comments like that. Certainly you know they only function well in ideal conditions: above 50% humidity and about 50F is where they can start to work, but the "bell curve" for performance will be around 80F and 80% humidity so it has plenty to draw from the air. All humidifiers (and air conditioners) depend on the purchaser properly selecting the device for the space and environment. A device like this can take the edge off a small room, like a bathroom, but that's about all. For anything demanding a Peltier unit won't cut it and you need a compressor based unit as mentioned.
Thermoelectric cooling generation is one of those things that's really cool in theory, and kinda crappy in practice. I tried building a TEC minifridge out of an old cooler and two Peltier units. It did work in the sense that it dropped the temperature of the cooler by a couple of degrees, but it required a ridiculous amount of power to do it. TEC power generation is about as equally worthless, but it is kinda cool, from a science point of view, getting a few volts from just the heat of a tea candle.
Bit of a long shot that you see this, but I was wondering if you could recommend resources and communities for someone to learn how to do something like making a dehumidifier with salvaged parts. Not necessarily exactly that, but the basics of how to approach that sort of scrapheap challenge engineering as a novice.
Hi I was wondering if you have ever looked at the electronics in a Chinese diesel heater? They are very basic but maybe you would have some suggestions for improvements that could be made to make them more reliable. Lots of people are using them now.
I know this is old. But out of curiosity: Isn't water collection dependent upon your RH? If it is not high, then less water is collected. Higher RH, then more water is collected? So, trying to get a lot of water from a 30 or 40 RH isn't going to produce much? (This is me just thinking out loud, please correct me if I am wrong, which I probably am, as I am ignorant with regards to dehumidifiers.)
I have a similar dehumidifier and it stopped working.It is just in a bigger box with two LEDs for ON and two LEDs for FULL on the front side. Nothing is moving now and all the lights are off.I have opened it to see if I can find what is wrong with it bearing in mind there is no many components inside( fan, peltier module and a few switches ). Maybe this is the best place to ask for advice. Lets me explain what I found and what is puzzling me.The power straight from entering the dehumidifier is around 13.7V. The negative is going to the small (main) circuit board .There is another small board with 4 LEDs( for ON and FULL) with 4 resistors on it. The positive is going to ON/OFF main power switch which is working fine . After that the positive is going to the switch for inserted water collection container( with switch for full tank next to it -the same as on the video).After that is going to the positive side of the same main board.When I measure ( with multimeter) the voltage from negative part of the board to the non inserted water container switch position is 13.6V.Of course, at that point, no power is going to the positive part of the main board and the fan is off( as the peltier module).The unexplained happens when I measure the voltage with water container switch inserted position.Instead of sending the power back to the main board with this switch in inserted position the voltage just disappears.When measured from negative electrode on the negative part of the board it disappears even before the main power switch( ON position).There is just no power at all.Where all the volts are ? I have also checked ( desoldering )the fan and peltier module and one 12V car battery they are working fine.Funny enough when connected directly to the original dehumidifier power source they are not working??? Also there is capacitor between the negative and positive part of the main board rated 25V and 47microF.When insulated it reads 54microF. Is this OK if it reads more than the rated number? Any help will be much appreciated?
If you're getting voltage into the unit it could be that a switch is faulty or that the power supply is faulty and its output is being pulled down by the load.
@@bigclivedotcom I will try to find similar 12V power supply and test again .Somehow my multimeter can't measure the amps( the risk when buying cheap chinese items) so I can not check what is coming out of the original power supply now.I will keep you updated.
After taking out and checking every component the voltage was still dropping with water tank switch on. After a lot time spent on the mystery disappearing voltage I finally found the problem. When checking voltage once (just at the back of the socket where the power plug is inserted )with multimeter the fan start spinning for a second.So it turns to be bad connection on the positive side of this socket.Quick soldering and now everything is working again.But was really interesting how this fault is letting the full voltage trough the main on/off switch up to the water tank inserted switch.I have to find probably replacement 12V socket but the dehumidifier is succefully repaired. I hope I can save some time to somebody with similar problem.
Hello, where I live during summer it gets to around 48°c - 52°c and right now we are experiencing very high humidity which is very bad ☹️ you cannot be outside, we are cloudy right now and I noticed the clouds literally disappear (probably because they are literally mixing with the humidity around the air. Right now is 12am and we have a temp of around 35°c and humidity 43%. 35 people have died in this month because of the extreme heat, do you think or could you do a video about these kind of humidifiers to see if this helps a little to at least bring the humidity down. I wanted to see if these would work to bring the humidity down and save on electricity for the people that are poor and cannot afford to pay high electricity bills
I replaced the Thermal paste with some cooler master thermal one , it did improve the performance of it , would be interesting to monitor both surfaces temperature...
I think the rubber washers are also to prevent heat conduction through the screws from one heat sink to the other. Having played about with a Peltier plate before the hot side seems to dominate the cold side substantially so I wonder if some kind of insulator other than air would be beneficial between the two heat sinks and perhaps nylon bolts instead of steel screws? Also would the condenser benefit from a bigger surface area and a rougher surface?
You know, I never really thought about using a peltier to _heat_ something. But it would be more efficient than simple resistive heating because you're already getting resistive heat PLUS whatever heat you've got flowing to the cold side of the junction...
so glad I came across this video I was thinking of buying this very model to keep keep humidity down in my holiday home when I'm not there. However after seeing this I'm a bit shocked at the price of them for what is inside. I could knock a DIY one of these up for next to nothing. (And probably will)
I want to know.what the way air in and out in this pleter module?because brusless DC fan is attached on the hot side.but we need cold air.if the cold side of the pleter module is not attached with any fan..how would actually we get.cold air from that.plz pal..I need to know
I'd interested to know if the 60W peltier cooler kits on ebay, which appear to be the same arrangement for £14, are any better than these units that cost £40...
+Ozric M. you chould, however it have the same problems as rainwater as its still will be polutet with what ever is in the air that will make contact with water like dust or smog. and i guess its quite an expensiv way of collecting water aswell as will only work if the air is humit allready so you whould have no luck trying to do so at greenland or in the sahara desert unfortunatly.the main reason to use one is to remove damp to provent molt in buildings or slowly try to dry books or something like that :)
I have one of these and found this video while searching to see if there was a filter inside that I could remove and clean to make it work better. Turns out, any dust it sucks in is probably sitting right on the components. After watching this video, I'm curious if it's worth pulling apart to clean, or whether I should just replace it with something more efficient for use in my small bathroom.
I tend to recommend using a real dehumidifier like the eco air simple which uses a rotating desiccant drum. They are much more efficient at pulling out a lot of water.
For the fun of it, try making a solid state dehumidifier. Take two stainless steel screens and place a hydoscopic salt in between. When there's no water the salt does not conduct, but as the salt absorbes moisture from the air it starts to conduct electricity that eventally breaks the water down to hydrogen and oxygen.
You'd be right to put that more towards the center. I see why it's not working that well too. The condensation heatsink isn't large enough. Neither is the dissipation heatsink. I think you could use the parts to make something far better though. Something with heat pipes would do a right nice job of it for the dissipation side. For the condensation side you want one of those old solid aluminium whoppers for the older AMD chips. Trust me when I say they work quite nicely for that...
so what side of the peltier is on the heatsink? i mean, if its the cool side, the cool side can make its own water out of nowhere , so was it water in the air or the peltier making it?
Old video, I remember watching it when you published it :) quick questions, do you think think would work better if the heatsink had fins like an air conditioning coil?
I wonder if the peltier was moved to the bottom of the heatsink in manufacturing, to ensure the heatsink is colder at the lower part to ensure the water doesn't evaporate again as it's travelling down the heatsink? Any Thoughts?
I was also thinking that the heat from the peltier makes it slide down over time which is why it was at the bottom. Also if it was in the middle wouldn't it collect more water making it drip onto the collection bin faster?
I have the newer version with LED lighting and have yet to find any information about opening it up and as a technician who works on phones, PCs, laptops etc can find no way to open it up. Now its full of dust and the fan needs replacing and I can't open it to do the job. Not pleased at all.
Hi @bigclivedotcom do you think a better way to extract the humidity would be cycling off the peltier for 30 seconds every 5 minutes or so to allow the freezing water on the cold side to drip? Thanks!
@@bigclivedotcom Yup tought about that also but tried to simplify to the max. Thank you very much for your quick reply and greetings from Buenos Aires, Argentina.
These Peltier modules do not like being switched on and off. I fitted a humidistat with a relay to turn it on and off. It stopped working after a few weeks and I had to fit a new Peltier.
@@Killadeniz They wer alright for a few months then stop working. I had 3 of them but could not keep them working. They fill with dust very quickly. Cleaning the dust from the outside is not good enough. You have to open them and clean all the heatsink fins. The peltiers fail quite often as well. I wondered if the peltiers were failing because of the shock of being switched on and off. So I put in an Arduino and a mosfet with pwm power control. Then the power changed very gently. They still failed. All in all not worth it. Threw them away and bought a 200W compresser dehumidifier. In 10 mins does what the little ones take a day to do.
what if you attach the fan on the cold side blowing out,would it turn into a mini air conditioner? maybe attach the hot side to a window so that the heat can be released.
would this work more efficiently if you were to have 4 Peltier's on the Large heat sink. and then back it with a heatsink of the same size on the opposite side?
Hey Clive. I live in Singapore. Past 4 yrs I went through 4 of these in my wardrobes and kitchen cupboards. They’re on 24/7 and only last about 8-10 months then they just stop working. This time though I didn’t want to chuck it in the bin and get a new one. I want to repair it. I found your video very helpful. Now I know exactly what’s inside but I was actually hoping to hear you tell us what could go wrong with them and how to fix it. If I actually replaced the module, is there a high chance that it will work again? Also, how would I know whether to change the fan too? This DIY enthusiast lady needs some expert help.😁
Suggestions for repairing mini dehumidifier: 1. disconnect power supply, check voltage is correct. (Poor quality capacitors are prone to failing.) 2. Check fan, use a small brush to remove dust. If it doesn't run smoothly a replacement (a superior quality/quietness) fan should be easy to source (local sources for spare PC parts, Amazon, AliExpress, Ebay ...). 3. The peltier modules can fail but before replacing that try just cleaning the module & replacing the heatsink compound.
I've been using one for years in a stored car, every winter. It's quite happily extracting a litre every few days and the full turn-off switch works fine. However, don't forget to empty it every so often, as when a big freeze occurs, the ice formed in the catch tank will crack it wide open. Of course, the availability of spares for these is non-existent.
As you found, the fan is nothing more than a cheap generic PC component - I replaced the OEM one after a year due to noisy bearings. The replacement, a decent quality Papst, has lasted for years.
One thing I found was the unit, more importantly, the power supply brick, wasn't immune to flood damage, and that killed it.
It lives on though; now being powered by an ATX PSU, the Peltier modules just chuntering away like they'll never give up.
In fact, I was so impressed by how it did its job, when it wasn't being nearly killed by weather and bad luck, I bought another one recently, to go into another car.
These things are ok for that size of volume, but for a room, forget it.
I don't want to break it but when did that stop me before. Lol. I love the fact you are part curious kid, knowledgeable engineer and intelligent comedian all in one.
love your vodcasts Clive they are always so informative. they tell me everything that I need to know about how a device works and therefore how to check it is functioning correctly and repair it if it is not
compressor (phase-change) cooling is so more efficient then these peltier fridges and dehumidifiers coming out. I have a compressor mini fridge that draws 45 watts (closer to 500w for a few seconds on startup) and can freeze everything solid, but have a relitive that has a peltier based mini-fridge and is always complaining that the internal temp is around 50 degrees, I put my kill-a-watt on it and it was drawing 200w, not to mention it'll never reach temperature and kick off unlike a compressor version.
The peltier fridges are terrible. very inefficient, but cheap to make and sell to people without actually mentioning that the running costs will be so massive.
They're really meant to be used for small, battery powered chillers. Or in small places like a gun vault or safe. Something to bring camping or on a picnic to keep things cold for a few hours. If you don't need it to be portable, phase change is absolutely the best option.
Didn't know you could get a 45W compressor cooler. A dehumidifier based on that would be convenient. Typical smallest is 220W.
You are hilarious! "It was certainly worth taking to bits" & "It's brand new but that's never stopped me before"! Thank you for the very educational video & the smiles.😁
Ahh good work, Clive! I've got one of these in an alcove for some defense while a neighbour's overflow pipe was keeping the outside wall wet. Thanks to your efforts here, I now won't have to risk busting it with my curiosity. Big Clive Public Information Service. My next coffee dedicated to you, sir.
I had a peltier CPU cooler in my monster rig build, back in 2007. It worked VERY well!
I used to use them way back in the late 90s, around the AMD K6 or Pentium III era. They worked very well unless the fan on your heat sink died, then they were capable of some extreme temps on the hot side and would typically burn out.
I bought like 8 of those peltier chips, a while ago. Finally I now have found a use for them
You are correct swapping the polarity changes the direction of the heat pump
Duh...
hey I got one of these and want to use it in my fridge i dont want a dessicant dehumidifier as it adds more heat what can i do to make it stop freezing up. I have a controller i can use to control the on/off and humidity %
@@ugursenturk5860 this will also generate heat. In order to make a cool side to collect condensation, the peltier must also have a hot side.
If the power supply output allows, you might be able to replace the peltier device with higher wattage one. If you use bigger one you may confront freezing problems instead of condensation, for that reason as you know, you cant go too far on that. You can make your own. Increasing heat sink area may solve freezing problem because it would dissipate the sub freezing cold which I know you know it very well.
I have a slightly larger one of these in a walk in wardrobe with an outside wall. we suffered much condensation mould. since using it we have no mould. they are good for small spaces like wardrobes.
Hi Clive, thanks for this teardown video. I've always wanted a small dehumidifier for a tiny room and had looked into the peltier-based models, but found $35USD+ way too expensive for what essentially is a peltier and a few heatsinks. Now that I know how these things work, I can use a few peltiers I have and some spare heatsinks to recreate this device for only the cost of my time.
Thanks again!
+Patty Two Wheels A recent test showed that the peltier unit was only about 20% as efficient as the desiccant drum unit. So the initial cost of the small unit would soon be outweighed by the running costs.
+bigclivedotcom and the full switch will never work and less one it changers its mind to how much water it wants to get out of the air
The point of the vid is this design is bad even when optimized it’s just a very ineffective way if you’re looking to actually draw a decent amount of water per day. This inherent limitation and slope of increasing inefficiency as the area around it comes to temp. His whole point is this would be completely ineffective in any practical sense. So I don’t suggest you waste your parts and time this way, Peltier modules as a whole are just super inefficient even with the high power units it would be terrible at this practically for condensation uses even with high power consumption. The math has been done and even with the most efficient end best units we can make it would still be wildly ineffective. Technically they work but there exist much better ways as even refrigeration with gasses abs compression is more efficient generally. Hence the self filling water bottle thing or the “water seer” devices and anything similar can never work and would barely provide a few sips of water a day. Sorry but they haven’t found a miracle that solves the water crisis so simply and easily. Keep in mind the Waterseer was a straight up scam and basically so is any similar fonts self filling bottle and they absolutely know it never word. And high school student could do the math to show what would be produced with the power used and the modules we can make and quickly find the idea as laughable and only works technically ever so slightly in (theory usually lol) as being a step away from free energy . Physics says so. Maybe try some of the other project uses for your spare unit and make something more useful and effective like a fridge. And you could do solar but the required panel would defeat the purpose and raise size and cost vastly. Wall power is cheap and likely available to you.
Of course it adds about 30W of heat to the space it's operating in, which lowers the humidity by raising the temperature. When I worked with my dad in a resort, there was a 100W light bulb in the outdoor box that contained the PA system, just to keep it a little warmer inside and prevent condensation that would mess up the electronics. So in a confined space like a linen closet, this peltier unit might be as effective as a 40W bulb.
Until a few days ago, I haven't heard of the Peltier effect. I got a mini dehumidifier for my bedroom. It does help. Maybe not as well as a dehumidifier that has a compressor.
Hi man! So basically if I were to have a fan, heat sink, cooling chip and a second heat sink I could build my own dehumidifier?
RCLifeOn or fridge. This is what those tiny mini fridges use, and why they can often warm cans up as well (by reversing polarity across the PD).
Instablaster.
I wouldn't have thought about a Peltier dehumidifier. I'm so used to the old fashioned refrigerated ones that it never occurred to me that that was an option. Nice find Clive. You dissect some of the neatest little gizmos.
It's really inefficient compared to the refrigeration and newer desiccant drum style dehumidifiers. More of a novelty than a useful device unless you have a small space needing kept dry with just a 12V supply. (Like a remote cabin with a solar panel.)
I don't feel so bad about my effort to make one now. I re-purposed a mini fridge to act as a dehumidifier and it was able to extract about a teaspoon an hour. The mains power one I bought takes out way more water.
I had to replace the fan on one of these and couldn't remember which way the it needs to face, thanks Clive!
The module is very cheap, you can get what I think is the exact same unit on ebay for $0.99. This is a 4 amp model, you can get a 15 amp version for $5.00.
My original intention for this humidifier was to use it for plants that require high moisture levels. After using it in my room, ua-cam.com/users/postUgkxtD9aJ2m6GU-X1IChQxjn9l31K1A7Kpwj however, I think that's where it is going to stay in the fall and winter season at least. The increased humidity in my room made the room warmer and more comfortable. I had first ran the humidifier for 4 hours with the timer setting for it. After the first hour, I checked my room and can feel the difference. When the full 4 hours was up, I checked again and noticed that the humidifier was shut off as it is suppose to. The moisture level never seem to get passed 56/57%. I then let it run until all the water is used up, which it wasn't all used up. There are still some left in the base that you are not suppose to add water to. I filled up the water tank all the way again, being careful when removing it from the base. Some left over water may spill out. After putting it back on and setting the unit to auto, I let it operate. It didn't stop running, rather I don't know if it did at any point since I didn't check it regularly, for 24 hours after which the water in the tank ran out. The moisture reading never passed 56/57%, which may be a good thing for me. Being situated right next to my bed, the noise was not very noticeable with the occasional water gurgle from time to time as the unit ran.
What the hell are you on about
This is a dehumidifier ...
i'm researching in regard to extracting water from air using desiccant surface. if a dehumidifier like this modifies in design it can produce considerable amount of water.
thank you for your video very useful
Congrats. you became an example against Pontus "The self-filling water bottle"
sWeasel511 no clue about what?
That's a rather ironic comment given that you spelled 2 out of the 4 words incorrectly.
lern how too spoke enlish!
If you reverse the polarity on the peltier junction, It won't just swap the hot and cold sides. It will in fact transport heat in the opposite direction but at a drastically reduced rate. They only really work in one way and therefore they must always be supplied as specified.
You are correct, if you change the heat sinks with larger sized ones in the cold side then you can eliminate that issue. Considering people would likely be hacking these devices for other purposes if they're changing polarity anyways, it's a simple matter to do. The peltier element itself works just as efficiently in either polarity, it's only the heatsinks that make a difference.
I got one of these its great works really well it lives in my little workshop I need to change its tank about once every 3 days. Yes it does make a slight 'snuffling' noise when its running but I find it nice
THANK YOU for this tear down :D. I wanted to see how they build it, now I know :D
i like your idea about running off a solar panel. I was thinking the same thing as im aware that these peltier devices are hugely inefficent from an energy perpective. I have a small area at the back of my garage of around 5sq m floor space that is insulated in which i keep my lathe and miller . I think im going to get one to stop flash rusting of the surfaces ( and add around 30watts of heat to the room)
Hey, hi from AU! Somehow missed this video, and nice to watch the teardown, tell you what these little things are great for - I have one in a small 60x60x50cm(ish) file cabinet/drawer I sealed and insulated and keep printer supplies in - where I am averages 75%rh and goes to 85%-90% quite regularly, this thing keeps 35C 35%rh almost all year round and produces a litre of water every six to eight weeks, excellent for old style lead acid batteries and I also use it to keep solder sponges wet and give the rest away to people that still do ironing... It's been going for almost three years now and reminds me why we like solid state devices...
lol no isolation between the heatsinks? and joined by a metal screw? and it actually have thermal paste that goes from one side to the other (@9:00).
i think, maybe, that's not very optimal.
Thanks for the video, helped me get going on repairing.
I have two of these that stopped working after a year. I’ve replaced the Peltier modules and they’re working well again. I wondered what makes them fail, maybe they were clogged with dust and too hot. Peltier spec. says max 60’C. The Peltier modules on eBay are 40 mm sq, bigger than the originals, but doesn’t seem to matter.
Various people have said that the hot heatsink is touching the air on the cold side, I’ve put foam there. Even worse, one of mine had a 50 mm * 2 mm gap allowing hot air into the cold side. Foam in there now. The gap is where the Peltier+heatsinks module does not quite fill the hole in in its plastic housing.
I also have one of these, it runs on only 9V. It has some additional component near the heat sinks, I guess it must be some kind of thermal switch (that either cuts out when the thing heats up too much or maybe when it would be on the verge of freezing). Because the fan is still rated at 12V, I added a ‘turbo’ switch with a booster circuit that brings it at full speed. Even then, performance is still very poor, although it helps a bit to get the moisture out of a poorly ventilated bathroom. But my big compressor-based dehumidifier pulls about 20 times the amount of moisture out of the air per Watt.
Alexander Thomas I've used a 'proper' dehumidifier to dry our washing indoors, and the amount of water it removed from the environment, even with no washing behind dried is impressive. Easily enough for two people to drink in case of emergencies wth a generator.
Good Video. Interesting to see whats in the dehumidifiers. Have one myself, it extracts 250ML s every day!
I have to say I was very impressed with the one I bought to get all the dampness out of my car. 600ml over the Xmas period in temperatures below freezing. For the price it did a fantastic job, how else to you get the inside of your car dry in winter. Clive, thanks for the breakdown.
I take it you must have run an external power supply to it? One of the applications where this thing would really work well is in a remote caravan with its own solar panel so that when there was enough sunshine the unit would trundle up and start extracting moisture from the interior and draining it to outside.
A bit late But, When you get close to the end of your journey turn off the heating in your car, open a window and let all the heat out of your car so the windows, seats etc, are the same temp as out side so condensation cannot build up with the heat difference, also when it's snowing out side try not to get snow inside your car of your shoes, get some rubber collector mats for your car, the type that have a grid cell pattern on them to collect the water off your shoes then you can just tip the collected water out of the car.
always worked for me and still do it to this day.
Now they changed for 9V adapter, possibly lower voltage for more longevity. Just acquired the same, fills the whole bucket in 1.5 days in my 80% room humidity here, despite that it's not able to lower it as unit is too small for room size I suspect.
Just did some quick maths on this one. The latent heat of evaporation of water is around the 100,000 joules per kilo mark. I think it's actually about 118,000 but 100,000 makes the maths easy. If your kit cools to the tune of 33W then it will take about hour to condense 1kg of water IF it's running at near 100% efficiency. The problem is that the hot bit and the cold bit are too close together so it is working at I would guess 10% efficiency at most.
Why the air is not pulled in from the hot side to the cold, so the temperature difference is greater and the effect would be more efficient? It is logical - just there must be additional air holes behind where the fan is and the fan should pull the air in. Then the air will go hot and then go to the cold side and then exit from the front air holes (not the back ones). And why the cold radiator is smaller then the hot one?
Great review. Thanks Clive. Surprised at how many of your videos I keep finding :-)
TES1-12704
TES (Thermo Electric Stack)
TES1 (one stage peltier)
127 (number of thermoelectric pairs
04 (max current 4amps)
This applies to almost all thermoelectric modules
TEC or TES is meant for cooling/ heating
And TEG is meant for power generation
Number afterwards marks how many stages there are
TES1 is most common but you can use TES2 to get slightly higher temperature difference it's basically two modules stacked ontop of each other tho one on colder side is usually 1/4 the power due to efficiency of these modules so you sacrafice efficiency.
Numbers after the "-" mark number of couples usually only first three and last two numbers mark the current.
That's all useful info, thanks.
Thanks for the video, I was looking for a mini dehumidifier for 3-D printing, and was looking at them hoping there was a big Clive teardown so I could see what was inside
If it's for filament storage, I use a large storage box with foam tape round the lid as a seal and a silica gel desiccant block with integrated heater for drying itself out when needed.
@@bigclivedotcom Thanks for the reply, any chance of a video of your setup, or have I missed it?
Good Video. good pace, good explaination, good teardown.
thank you for taking the time. was always curious.
This little dehumidifiers works for what is intended to be used, it will not replace a compressor style dehumidifier, but for small spaces like small RV trailers, it will work perfectly. a piece of foam around the peltier will help the cooling and heat effect.
We had a 'mini cooler' at work until some bright spark switched it from cold to hot while still turned on. A loud bang and flash was emitted and muggins here was asked if i could fix it. took it home, the 'hot/cold' switch simply reversed polarity of peltier and had shorted in the middle, melting on/off switch and hot/cold switch into one blob of plastic, and a very charred circuit under them. I took it all apart, sandwiched peltier between original heatsink and a cpu heatsink, fans on both sides, wired it to 12v cpu header on a spare pc power supply rated over 400w. Fans came on and one side gets lovely and cold and the back gets barely warm given its massive heatsink lol. it now sits in a round cliplock container next to my bed waiting for those ugly sweaty long summer nights blowing a chilly cold breeze across my face :D Instant cheap air con, yay !!
the hot and cold air flows are kept completely separate from each other, not (asking rethorically)
It could work in a small enclosed space to reduce moisture.
I've been using these for like. 7 years... I leave it in a cupboard I keep my. Guitars.... For where I live, SEA, I can keep humidity at 60 percent while outside hovers around 75 to 85 percent... Not bad... they are robust and still works after 7byears, However the adapter have given up on me twice. I think that's because the temperature of the cabinet sometimes exceeds 32 deg celcius, adapter overheats
Those are great !!! I bought 3 dozen of them. Still haven't found a personal use for them, though. Maybe around my boiler
and drained outdoors will keep the rust down. Now to buy large heat sinks. Note to self: when using several in one
gadget, it's probably best to leave decent air gaps between them.
My first thoughts were solar-powered water collection as well -did you develop the idea further Clive?
If you ask me, the cooling heatsink doesn't look as big as it could be, and neither is the airflow optimised properly. It looks like a half-baked design, to be honest. You might dramatically improve the performance (proportionally, that is) by slapping on a much bigger cooling heatsink and improving the flow so that the incoming air has to go through the heatsink from top to bottom (or bottom to top), and making sure the outgoing air doesn't interfere with the incoming air.
The size of the cooling heatsink is probably deliberately small to increase the temperature differential between it and the incoming air. the airflow does run down the channels of the heatsink before passing round the back to the hot side.
There's a very good chance this IS the actual optimised design, but it's just very inefficient by its nature.
bigclivedotcom Does the air flow from cold side to hot side? The other way preheated air should gain higher temperature difference in cold side and better efficiency.
Cmazy That would make it extract even less water than it does already! The rh would drop due to the pre-heating, and the cooling side would then just take it back to the original rh and temperature, probably getting nowhere near the dew point.
+bigclivedotcom It doesn't look as though there's adequate air flow through the cold heatsink. It should be pushing as well as pulling. Also, what was the exhaust air temperature? A dehumidifier should be temperature-neutral as far as possible. The peltier seems a bit underpowered as well. The part number 12704 means 127 thermocouple elements and 4 amps design current. But these things are very sensitive to supply voltage. If it's running on 12 volts, it will barely work at all. At 15 volts, there will be a huge difference in efficiency.
He said "from cold to hot" and that would increase the performance a lot, thats how all (real) dehumidifyers work. That way a lot less energy is wasted to cool down air when u actually just want to put energy into condensing water, as the cold air cooles the hot side it makes the cold side even colder. So it basically regenerates (some of) the energy put into cooling the air.
I have often wondered if a Peliter device would be a very good to use to make distilled water. The hot side could be used to evaporate water and the cold side could be used to re-condense it. This should result in a very efficient system. The losses in the Peltier are associated with the devices resistance. By stacking, the necessary temperature difference could be maintained.
I have seen such devices used in cabinet rack cooling for telecoms and computer equipment. The advantage of such a system is that the electronics can be sealed from the outside environment, allowing the humidity within the rack to be limited with silica gel packs.
Peltier panels are simple and convenient, but not really efficient. However, it's always worth experimenting.
I have had 6 or 7 of these around, bought in batches of 2 or 3, and two a little larger ones. I always knew they won't be the "best thing ever", but it was mainly for space reasons that we got the small peltier ones (e. g. outside wall corner in parent's basement and bathroom, in corners on shelves i my basement), but I did not expect them to perform that bad. After 2 summers of use all the fans are rattling like crazy and all but two of the power supplied died due to failed caps, just what you expected in the description. They were just barely doing their job. Their main effect of getting the air drier is actually just heating it so relative humidity drops. Perltiers are horribly inefficient. If I remember correctly it was something like for every degree the cold side gets colder, the hot side rises by 10.
In our basement we now installed some 125mm air ducts from room to room with two fans, so the air is pumped through all rooms in a circle. In one of the rooms there's a compressor dehumidifier (around 300W). It replaced two of the bigger and 4 of the smaller peltier dehumidifiers. This single device is enough to keep all the basement rooms around 65% rH, even in the problematic corners and after days and weeks of 30°C+ weather.
So in essence: you're much better off getting an old fridge and leaving it running with the door open than to buy those crappy peltier things.
So there's no air flow from the axial fan directly on to the cold side heat sink? The fan just blows air on to the hot side heat sink?
Mine has a flashing green light any ideas had it apart power is reaching fan because it's moving slightly but not going around
It may be a power supply issue or a thermal cutout has tripped.
Its' interesting that the old big clunky fridge-style dehumidifiers seem to go much further and freeze the water and then cycle to melt that into the bucket rather than just relying on just condensing based on reduced capacity.
Sounds like inefficient operation, wonder if the customers prefered it because it seemed more powerful or something... or if the thermostat just wasn't very precise.
I once had to look after a computer room that was cooled by a window mounted A/C unit (we don't have these very often in the UK)
when it was working properly it dripped water onto the flue of the pizza restraunt downstairs and put it's boiler out. when it wasn't working properly (usually because a colleague had mucked about with the thermostat) you got ice climbing out through the front grill
It is impossible to choose one correct quantity of air flow and coil temperature for every condition so they designed them to work that way when working in colder conditions.
Dehumidifiers that freeze up are not running properly, just like A/C units that freeze up.
these are quite handy for drying shoes and such. that's what I use them for at least. in the humid summer months they can bring out about a tank worth a day which is not bad for it's size, but yeah if you need a real dehumidifier you should get one.
I guess it could swap polarity every so often to defrost itself? (If used somewhere like a car where temps might get too cold?)
12704, about 4 amper. That easy to over heat. The reason why cheap dehumidifiers using small amper are to get fast sublimation. But it's forcing the so much.
I have one of these, and i am hoping you might be able to tell me why it stopped working. i turned it off for a few days and now when i turn it on both the power and full lights blink and nothing else happens. the water tray is definitely pushed in. thanks
Thanks a lot!
I bought one of these in the begining of the year, but haven't used for some months. When I turned it on, it started a strong noise. By seeing your video I imagined that the problem was in the cooler. So I opened it, cleaned everything, put some new lub in the cooler and ... it worked! :)
What type of screwdriver do you used to opened?
i'm so glad the production of your videos has improved.
hey but how does air from hot part pass to the cold part. the peltier are stuck together. so how does 12v fan passes the air from hot part to cold part
There is one thing they forgot in the design.....
I have exactly the same dehumidifier running in my shed, but when the temperature in the shed goes below about 8°C the cold side heatsink becomes one big lump of ice !
So I added a 10° clixon to turn it off....
(also added a drain hose so I don't have to empty it manually 😄)
I have the exact one in my towel closet. It was going alright for about a year then he bearings went on the fan. Just replaced it with a Noctua one. Next I was going to see if I could make it battery powered so I can out it in closets without a power point
Great video. Would using a larger Peltier module or larger cold sink make it more effective?
These things can never be efficient, even in their absolute optimum operating conditions.
Without a mention of the humidity you exposed it to, and the temperature and square footage of the space, and the exact time allotted for the device to run, there is no way to determine whether the small amount of water you found is reasonable for such a small device or not. When attempting to review a product try to think of all the relevant parameters to pass on as without them you could be misleading people with comments like that.
Certainly you know they only function well in ideal conditions: above 50% humidity and about 50F is where they can start to work, but the "bell curve" for performance will be around 80F and 80% humidity so it has plenty to draw from the air.
All humidifiers (and air conditioners) depend on the purchaser properly selecting the device for the space and environment. A device like this can take the edge off a small room, like a bathroom, but that's about all. For anything demanding a Peltier unit won't cut it and you need a compressor based unit as mentioned.
What size 12v fan is that? 80mm?
Thermoelectric cooling generation is one of those things that's really cool in theory, and kinda crappy in practice. I tried building a TEC minifridge out of an old cooler and two Peltier units. It did work in the sense that it dropped the temperature of the cooler by a couple of degrees, but it required a ridiculous amount of power to do it. TEC power generation is about as equally worthless, but it is kinda cool, from a science point of view, getting a few volts from just the heat of a tea candle.
Bit of a long shot that you see this, but I was wondering if you could recommend resources and communities for someone to learn how to do something like making a dehumidifier with salvaged parts.
Not necessarily exactly that, but the basics of how to approach that sort of scrapheap challenge engineering as a novice.
Technology connections
Hi I was wondering if you have ever looked at the electronics in a Chinese diesel heater? They are very basic but maybe you would have some suggestions for improvements that could be made to make them more reliable. Lots of people are using them now.
I have a couple of the heaters here.
I know this is old. But out of curiosity: Isn't water collection dependent upon your RH? If it is not high, then less water is collected. Higher RH, then more water is collected? So, trying to get a lot of water from a 30 or 40 RH isn't going to produce much? (This is me just thinking out loud, please correct me if I am wrong, which I probably am, as I am ignorant with regards to dehumidifiers.)
I have a similar dehumidifier and it stopped working.It is just in a bigger box with two LEDs for ON and two LEDs for FULL on the front side. Nothing is moving now and all the lights are off.I have opened it to see if I can find what is wrong with it bearing in mind there is no many components inside( fan, peltier module and a few switches ). Maybe this is the best place to ask for advice. Lets me explain what I found and what is puzzling me.The power straight from entering the dehumidifier is around 13.7V. The negative is going to the small (main) circuit board .There is another small board with 4 LEDs( for ON and FULL) with 4 resistors on it. The positive is going to ON/OFF main power switch which is working fine . After that the positive is going to the switch for inserted water collection container( with switch for full tank next to it -the same as on the video).After that is going to the positive side of the same main board.When I measure ( with multimeter) the voltage from negative part of the board to the non inserted water container switch position is 13.6V.Of course, at that point, no power is going to the positive part of the main board and the fan is off( as the peltier module).The unexplained happens when I measure the voltage with water container switch inserted position.Instead of sending the power back to the main board with this switch in inserted position the voltage just disappears.When measured from negative electrode on the negative part of the board it disappears even before the main power switch( ON position).There is just no power at all.Where all the volts are ?
I have also checked ( desoldering )the fan and peltier module and one 12V car battery they are working fine.Funny enough when connected directly to the original dehumidifier power source they are not working???
Also there is capacitor between the negative and positive part of the main board rated 25V and 47microF.When insulated it reads 54microF. Is this OK if it reads more than the rated number?
Any help will be much appreciated?
If you're getting voltage into the unit it could be that a switch is faulty or that the power supply is faulty and its output is being pulled down by the load.
@@bigclivedotcom I will try to find similar 12V power supply and test again .Somehow my multimeter can't measure the amps( the risk when buying cheap chinese items) so I can not check what is coming out of the original power supply now.I will keep you updated.
After taking out and checking every component the voltage was still dropping with water tank switch on. After a lot time spent on the mystery disappearing voltage I finally found the problem. When checking voltage once (just at the back of the socket where the power plug is inserted )with multimeter the fan start spinning for a second.So it turns to be bad connection on the positive side of this socket.Quick soldering and now everything is working again.But was really interesting how this fault is letting the full voltage trough the main on/off switch up to the water tank inserted switch.I have to find probably replacement 12V socket but the dehumidifier is succefully repaired.
I hope I can save some time to somebody with similar problem.
Hello, where I live during summer it gets to around 48°c - 52°c and right now we are experiencing very high humidity which is very bad ☹️ you cannot be outside, we are cloudy right now and I noticed the clouds literally disappear (probably because they are literally mixing with the humidity around the air. Right now is 12am and we have a temp of around 35°c and humidity 43%. 35 people have died in this month because of the extreme heat, do you think or could you do a video about these kind of humidifiers to see if this helps a little to at least bring the humidity down. I wanted to see if these would work to bring the humidity down and save on electricity for the people that are poor and cannot afford to pay high electricity bills
I replaced the Thermal paste with some cooler master thermal one , it did improve the performance of it , would be interesting to monitor both surfaces temperature...
I noticed that this unit seemed to have an excess of heat sink compound.
I got the larger version of this after a major leak in the house; it took only two days to dry the carpet in the room affected
I think the rubber washers are also to prevent heat conduction through the screws from one heat sink to the other. Having played about with a Peltier plate before the hot side seems to dominate the cold side substantially so I wonder if some kind of insulator other than air would be beneficial between the two heat sinks and perhaps nylon bolts instead of steel screws? Also would the condenser benefit from a bigger surface area and a rougher surface?
You know, I never really thought about using a peltier to _heat_ something. But it would be more efficient than simple resistive heating because you're already getting resistive heat PLUS whatever heat you've got flowing to the cold side of the junction...
so glad I came across this video
I was thinking of buying this very model to keep keep humidity down in my holiday home when I'm not there. However after seeing this I'm a bit shocked at the price of them for what is inside.
I could knock a DIY one of these up for next to nothing. (And probably will)
I want to know.what the way air in and out in this pleter module?because brusless DC fan is attached on the hot side.but we need cold air.if the cold side of the pleter module is not attached with any fan..how would actually we get.cold air from that.plz pal..I need to know
I'd interested to know if the 60W peltier cooler kits on ebay, which appear to be the same arrangement for £14, are any better than these units that cost £40...
Seems like this would work well for a car or small bathroom to get rid of excess moisture.
Now, would running one of these outside on a humid day collect water? Could these be in some way a way to collect water from the air?
+Ozric M. you chould, however it have the same problems as rainwater as its still will be polutet with what ever is in the air that will make contact with water like dust or smog. and i guess its quite an expensiv way of collecting water aswell as will only work if the air is humit allready so you whould have no luck trying to do so at greenland or in the sahara desert unfortunatly.the main reason to use one is to remove damp to provent molt in buildings or slowly try to dry books or something like that :)
leave a bucket outside than u has water :D
Then you have that useless self-filling water bottle thing. You're much better off collecting rainwater.
I have one of these and found this video while searching to see if there was a filter inside that I could remove and clean to make it work better. Turns out, any dust it sucks in is probably sitting right on the components. After watching this video, I'm curious if it's worth pulling apart to clean, or whether I should just replace it with something more efficient for use in my small bathroom.
I tend to recommend using a real dehumidifier like the eco air simple which uses a rotating desiccant drum. They are much more efficient at pulling out a lot of water.
hello sir, is the cooler 80mm or 120mm? Thank you
my gf shoved the plunger inside the water receiver, any tips for opening the water receiver?
thx!
There is no fan on the cold side? would it be more efficient if it had one? Or is the hot side fan circulating air on the cold side too?
It pulls the air in across the cold side before passing it over the hot side.
For the fun of it, try making a solid state dehumidifier. Take two stainless steel screens and place a hydoscopic salt in between. When there's no water the salt does not conduct, but as the salt absorbes moisture from the air it starts to conduct electricity that eventally breaks the water down to hydrogen and oxygen.
You'd be right to put that more towards the center. I see why it's not working that well too. The condensation heatsink isn't large enough. Neither is the dissipation heatsink. I think you could use the parts to make something far better though. Something with heat pipes would do a right nice job of it for the dissipation side. For the condensation side you want one of those old solid aluminium whoppers for the older AMD chips. Trust me when I say they work quite nicely for that...
You have to be careful, if you make the Peltier too efficient the cold side will get cold enough to freeze the water and it won't work properly.
There's no fan to draw damp air across the cold side?! Wouldn't it work better if there was?
One fan draws air across both.
so what side of the peltier is on the heatsink? i mean, if its the cool side, the cool side can make its own water out of nowhere , so was it water in the air or the peltier making it?
Either side can heat or cool depending on polarity. The water is condensed out of the air by a cold surface.
@@bigclivedotcom i will have to build one myself to see , i dont want to disasemble one and void the warrenty lol
Hi all the yellow cable on the micro switch is off on my one not sure what one to put it back to
why don't they add more peltier and make it work a little bit more. i love Peltier. i hope it will be the future of a/c
Old video, I remember watching it when you published it :) quick questions, do you think think would work better if the heatsink had fins like an air conditioning coil?
I wonder if the peltier was moved to the bottom of the heatsink in manufacturing, to ensure the heatsink is colder at the lower part to ensure the water doesn't evaporate again as it's travelling down the heatsink? Any Thoughts?
I was also thinking that the heat from the peltier makes it slide down over time which is why it was at the bottom.
Also if it was in the middle wouldn't it collect more water making it drip onto the collection bin faster?
I don't think so, looking at the heatsink compound it doesn't look like it has moved, otherwise there would be gunk all the way down.
Nice job and saved me a bunch of money.
+Alter Kater probably built one
***** some dehumidifiers are a waste of money
Hi friend the fan in my one starting to make noise where can I get a quite one
I have the newer version with LED lighting and have yet to find any information about opening it up and as a technician who works on phones, PCs, laptops etc can find no way to open it up.
Now its full of dust and the fan needs replacing and I can't open it to do the job. Not pleased at all.
It will have concealed screws. The puzzle is to find them all.
what size was the peltier chip. was it 40x40? maybe a 6 amp rating?
Does this device release cold air?
I think the air conditioners are enough to absorb moist air!
Hi @bigclivedotcom do you think a better way to extract the humidity would be cycling off the peltier for 30 seconds every 5 minutes or so to allow the freezing water on the cold side to drip? Thanks!
I'm not sure. One option might be to turn the fan off and reverse the polarity briefly to warm the condensing surface.
@@bigclivedotcom Yup tought about that also but tried to simplify to the max. Thank you very much for your quick reply and greetings from Buenos Aires, Argentina.
These Peltier modules do not like being switched on and off. I fitted a humidistat with a relay to turn it on and off. It stopped working after a few weeks and I had to fit a new Peltier.
@@RichardDTube Any success on the new peltier, or did they break too?
@@Killadeniz They wer alright for a few months then stop working. I had 3 of them but could not keep them working. They fill with dust very quickly. Cleaning the dust from the outside is not good enough. You have to open them and clean all the heatsink fins. The peltiers fail quite often as well. I wondered if the peltiers were failing because of the shock of being switched on and off. So I put in an Arduino and a mosfet with pwm power control. Then the power changed very gently. They still failed. All in all not worth it. Threw them away and bought a 200W compresser dehumidifier. In 10 mins does what the little ones take a day to do.
what if you attach the fan on the cold side blowing out,would it turn into a mini air conditioner? maybe attach the hot side to a window so that the heat can be released.
You have to vent the hot side out, or it will heat the room (it puts out more hot air than cold air). It would be a VERY mini A/C.
would this work more efficiently if you were to have 4 Peltier's on the Large heat sink. and then back it with a heatsink of the same size on the opposite side?
I'd guess it might help, but the airflow is also a really important factor.
Hey Clive. I live in Singapore. Past 4 yrs I went through 4 of these in my wardrobes and kitchen cupboards. They’re on 24/7 and only last about 8-10 months then they just stop working. This time though I didn’t want to chuck it in the bin and get a new one. I want to repair it. I found your video very helpful. Now I know exactly what’s inside but I was actually hoping to hear you tell us what could go wrong with them and how to fix it. If I actually replaced the module, is there a high chance that it will work again? Also, how would I know whether to change the fan too? This DIY enthusiast lady needs some expert help.😁
Suggestions for repairing mini dehumidifier:
1. disconnect power supply, check voltage is correct. (Poor quality capacitors are prone to failing.)
2. Check fan, use a small brush to remove dust. If it doesn't run smoothly a replacement (a superior quality/quietness) fan should be easy to source (local sources for spare PC parts, Amazon, AliExpress, Ebay ...).
3. The peltier modules can fail but before replacing that try just cleaning the module & replacing the heatsink compound.