@@Okurka. They'll make 2 versions (1) for us mere mortals that will be impossible to open. (2) a Big Clive version that opens instantly upon arrival, so he can re-engineer their poor design.
Don't need to add the extra diode, or remove the pair of low value resistors tho' - with just the 18 ohm resistors removed, the LEDs will block the reverse current path.
I dreaded working with SMD components for a long time. Partly because they're so tiny and my hands are a bit shaky, but also because it meant I'd have to buy a whole lot more components. But then I saw a few projects on the Interwebs that I wanted to build, but they were all SMD. So I bit the bullet and ordered the boards and parts, and gave it a go. To my surprise, it wasn't nearly as difficult as I thought. It didn't take long to get used to the tiny components, even with my unsteady hands. I even built one of Rasteri's weeCee tiny PCs, which required aligning 1.25mm twin row SMD headers within a fraction of a mm on four sides to fit the processor module. Now I've designed my own projects that use SMD parts, designed the boards got them manufactured and everything. I've even printed and etched my own home made boards using the toner transfer method. Basically the only reason I'd go for through hole over SMD is if I wanted to use a specific through hole part (potentiometer, header pins, specific IC that I already had in through hole version), or if I wanted the circuit to look vintage (I'm currently designing a clock that uses a vintage VFD display, housed in a wood and acrylic case that shows off both the VFD and the PCB).
you don't have to replace the 5.1 ohms with a diode if you cut out the 18 ohm resistors, because the reverse breakdown of the LED's will be higher than the battery voltage so the LED's will block current from flowing back into the charger and discharging the cells.
Your NiMh trickle charger was one of the first projects I did getting back into electronics this last year. I use portable radios pretty heavily in my day to day and having a set of batteries ready to go at all times is really convenient. Thanks for doing what you do!
I was taught electronics when I educated as a Radio TV Repair tech in the late 90s, and SMD was just a side notice.. Got my certificate and there was no work so I went into telecoms instead. Been there in various jobs since then, until recently when I started working in an electronics factory and Oh sweet lord this stuff is tiny.. My glasses need glasses for some of the stuff :D What I learned pretty early though, is get yourself a syringe of flux paste, and just jab that on there before you solder the component down, and also a sharper tip helps. The flux will really help spreading the heat, and the sharp tip will make it less messy.
What a lovely follow up! Just last weekend I was thinking about building your previous trickle charger… but instead I just ordered one of these and will just remove the resistor. Thanks as always for the entertaining and educational watch!
When digital point and shoot cameras used AA batteries, customers were often impatient and wanted their batteries to charge fast !! ... there were a lot of 'Fast Chargers' sold, and I am sure they Nuked the poor NiMH cells ... I tried to sell a slower charger and a spare set of cells, but not everybody could be taught ;)
I can recall Dave @EEVblog showcasing and investigating a fast charger. IIRC, 4A per cell, or even more, since it is said NiMH can withstand it when done right.
Photographers aren't really known for their intellect or practical skills, so it's no surprise the general public exposed to technology would fail just as professional and amateur photographers would.
I guess the Schottky diode is belt and suspenders, because the "D" in "LED" is for "diode"; the current should only go in one direction through either.
I'm glad you brought up the point that the modified charger was intended to "top off" charged batteries. Basically the idea is to provide just enough current to overcome the cells internal resistance. That's actually called maintenance charging. I designed a 12.6v gel cell charger based on a 7815 series regulator that provides it's output based on the state of the battery. The charging current will be 1 amp when the battery is discharged and will taper off to about 8 ma at full charge. I chose the 8 ma value based on the data sheet for the battery. The charger and battery are in an emergency lighting system I built almost 10 years ago. The battery has lived well beyond it's natural life thanks to maintenance charging. With regards to surface mount components, I would recommend getting a microscope to assist in placement especially for the 0805 and 0603 parts. I have a Mustool microscope that has it's own display and can magnify up to 600x. It wasn't that expensive- under $50 USD (41 GBP) on Amazon. As a radio amateur I receive the ARRL's QST magazine and a couple of years back they ran an article about using a PC cam as an alternate to a microscope. I tried it and it's doable but it is cumbersome and the magnification is limited. Solder paste is a much better alternative to fluxed solid solder as a dab will hold the part in place until you put pressure on it with tweezers. Also you get better control of the amount of solder on the pad. As to the type of tweezers the ceramic tipped ones are ok for passive components but not so good for actives such as MMICs where they might be subject to static damage. For that reason I have a grounded mat on my bench and use conductive tweezers when I'm working with actives. My workspace is a scaled down version of what I used to use back before I retired. Finally, a schottky diode would have been my first choice since it has a forward voltage drop of about .1v as opposed to .6v for a standard PN junction diode. At 40ma the diode will dissipate only about 4mw. Later.
I'm glad you mentioned the potential resistance of the USB cable. I'm also glad you mentioned reverse discharging because thats exactly what my TOMO M4 18650 power bank does that i got in 2019, so after charging 18650s with it if i dont plan on using the power bank i started removing them to stop that from happening.
Would very much like to see you do a dedicated video on how to reverse engineer a circuit board, from analysing the board to producing a schematic diagram.
im so glad im ultra near sighted. ive never needed a magnify glass since my eyes have a focal distance of 1.5 inches. in electronics class i was the only one able to do smd chips and ics without a microscope. so the teachers had to debate how to grade me since i had a advantage over all the other students.
My eyesight is the same way. I think my main concern if I got into electronics would just be protecting my eyes when working with tools at such close distances.
Being near sighted myself I have always had an advantage when working with small parts but take it from me when you get down to 0402 pitch and smaller parts you will need a microscope. The 01005 parts are not much bigger than a grain of sand.
Clive, I appreciate the recommendation on the ceramic tweezers. I grabbed some a while back after you mentioned them in another video, and they're great! They work nicely for hot air soldering of SMD stuff, too. Mine use black ceramic, supposedly ESD-safe, but I don't know if I trust that.
I would assume that the current draw had been limited to 500mA, which is the default limit for USB in the absence of shorted data lines, weird resistor combinations, or current negotiation.
there is no 'negotiation', is just a straight resistive current limit circuit, similar to most mains powered nicad/nimh chargers although one i have is more like the previous 'rougher' one, relying on the resistance of the transformer secondary wire to limit current !! you could even use a small bulb as current limiter, i've done a few times, for this a 6v 0.04a in each channel would do nicely , although not easy to find, 0.06a ones bit easier
The original USB spec was 100 mA (the pre-negotiated value) and 500 mA (the post negotiated value). The problem with that is that SOMETHING had to be able to limit the currents, and that semiconductor was $$$. Most of the Asian-supplied PCs were focused on low cost, so they omitted the current-limiting circuitry to save money. You often had the PC's raw 5V supply wired directly to the VBUS leads on the USB ports. In time, most PC guys threw up their hands and said "why bother?" and current was no longer limited. Now you have little 5V 1A and 2A wall warts that have no real current limiting to them. I recall long ago when the PC guys inquired of Apple what it would cost to add Apple's Firewire ports on their machines. Apple's reply was $1/port. They were outraged, saying that a USB port's cost was about 1/4th of that. Apple then tried to backpeddle and lower the licensing price, but the damage was done. How many PCs did you see with Firewire ports (before Apple killed Firewire)? My point being that PC manufacturers are extremely cost-conscious.
Was excited for this, I ordered from eBay what I thought was the same charger, but I got something with a slightly different PCB on it. PCB has a model number "MQ B-04". Traces are slightly different two 1.1 or 1 ohm coming off positive, the resistors seem swapped 22ohm in series with led and 150 going to positive contact. Resistor groupings on the board is different from your example, where resistors outside the first ones on the positive side input are placed around each positive battery terminal and led. Interesting with the differences between your example, and the one I got from eBay.
I got one from AliExpress and expected the same. The one I got had the exact schematic as Clive drew on the previous video (one R parallel with an R and an LED). Different PCB layout and values though (1k in series with the LED and parallel to a 24R). I removed the 24R and now I wonder if using a 1k and LED in series with the cell even charges it at all. There is current flowing because the LEDs light up (quite well, actually)
I wear an old ww2 mask when using it. Come back after a day and the joint is corroded. Gives it an antique finish and Tom cats around. That way the project also gets a cat scan at the same time. Win win all around.
that is funny that you bring out a NIMH charger video again. I recently made a charger using one of your videos. Only things that I changed was USB-C compatible with the 5.1k resistors and I made one bay fast(er) charging with a lower resistor value. With shipping and making only one, it still came to about the same price as a cheap charger on amazon.
Yet another undocumented benefit: You can use it to balance cells which are to be used in series in an applience by just letting them in there after charging, and disconnect only the USB plug. After a few days a quick boost by topping them up, and they should be balanced.
I use Nitecore chargers...single, dual & quad...for my batteries...Eneloop AA & AAA...plus Samsung 18650's. They work great and have not failed to charge nor have they overcharged to date.
Back in the days then I was young and naive I "hacked" one of those spring loaded chargers, basically threw out all the circuitry and just added a connector to hook it to a RC battery charger. I needed to charge 4 eneloop at a time (for Tamiya mini4wd models). Turns out the springs can't bear a 2A charge, they get super hot and melt. Lesson learned!
The schottky diode is not so needed, because the LEDs also are in series with the batteries, unless you do not trust them to block the back flow. And in your drawing, you did not cross out the two 5Ω1 resistors
Rite Big Dude, Neat little hack. I was using my ceramic tweezers the other day and thought, wonder if Clive still uses his as I haven't seen them for a while! Love mine so thanks for pointing them out. TFS, GB :)
Delightful. Good to see that surface mount is not so scary, and a nice tool tip about the tweezers at the end. I have actually built a 3 board version of the Simple NiMH battery charger (with PCB files) Big Clive showed us how to make. 👍🙂👍
By the way, they sell 8W rechargeable soldering irons based on a similar to EVOD devices design and 510 screw-on soldering pieces (those you showcased before). They aren't very powerful and don't last much off of full charge; yet, they can save you in the field / during a power outage. Moreover, they started to sell like more powerful soldering pieces with a set of changeable tips and spare heating elements, and bigger announced heating power, which could make them a better solutions for owners of more powerful battery mods. Have you tried these ones yet? I'm asking because even these eight-watts things are not as bad as I expected, and if you ever happen to get yourself the newer version, it'd be quite interesting to hear your review.
all these weirdos telling me i need tweezers and a magnifying lens and a tiny soldering tip meanwhile you're out here rawdogging it with a standard tip and just wiping them off. well, guess i learned something today.
I converted a GP 'overnight' charger for 2x2 cells into a 4x1 cells trickle charger. Mainly because the unit in its original shape could not charge 1 or 3 cells, but also because it slightly warmed up the cells when using it as a trickle charger.
The diode at 6:28 should be in series, not in parallel to the 2 resistors. Reverse current will still flow through the 2 parallel resistors. As others have said if the 18 ohm resistors are removed the extra diode isn't needed at all as the LEDs will do the job.
It's *amazing* , how you recognise with your knowledge a faulty/not ideal product, analyse the manufacturer's mistake(s) and improve the product to your needs with just some touches with the soldering iron and one available component out of the box! 😃👍
@@u.e.u.e. he taught me a lot, while simply doing things he himself enjoys and talking whatever he likes. The way he presents knowledge and technicalities is just priceless and easy.
I was going to mention it will do its best at revitalizing «dead» NiMH cells your smart chargers won't agree to recognize, and it will recover them in the safest manner possible. But you said it right away.
My first thought about the big and little resistor in parallel is that the design was meant to be used with one or the other depending on if you need extra dissipation or can go with one size of resistor. Someone just decided to populate both in the end and maybe double the value to end up with the 2.something ohms.
for nicd and nimh that circuitry is not bad at all . in the 80s often the dc from the power supply could just go to the cells and that was fine for charging nicd and nimh. today's lithium even the lifepo4 and lto variants require more advanced circuitry than a simple resistor to limit current.
The schottky diode is actually superfluous, the LED’s will provide reverse protection on their own. Solder bridge the schottky, you’ll get a slight bump in charge current to boot.
I do have some NiMH AA and AAA cells. For instance, I've been using NiMH AA ones in my wireless mouse every day for more than ten years already; and I can't really tell how many days or weeks it takes to discharge one cell. The mouse has a boost circuit in it, so it drains the cell quicker, but doesn't require two (thus neither weighs significantly more, nor falls to using two AAAs). Those cells I bought before switching to this wireless mouse are still with me, and I honestly can't really even tell which of them all were bought a bit later; maybe only by date codes, or measuring their capacity degradation. I used to think NiCd cells are better for low-current applications: I've been told they have smaller self-discharge current. But, again, after more than ten years of using NiMH cells every day, I can't complain. Initially, I didn't really like Lithium cells when they started appearing here and there, I was even more dumb and incompetent than I am now (surprisingly, it was possible!), plus they weren't as good as they can be today. Nowadays, I still like NiMH cells, already like Lithium cells (recently found three discarded POD units, one of them is rechargeable and supports cartridges with e-liquid and mesh heater), but my observations show that NiCd cells are leaving us: they suffer from memory effects similar to those of NiMH ones, they chemically degrade like faster, and their capacity per weight and per volume haven't been improved lately by the manufacturers. I may be wrong (and I often tend to be), but this is my personal experience.
I'll share my tip for surface mount components, you need a stick of paper glue and a cocktail stick. Put a tiny bit of glue in the middle of the component with one end of the stick & place it on the pcb. Then using the other end apply a little pressure to keep it there while you solder it.
That's if the current to be passed from a 'Host' has been negotiated via protocol with an attached device. Most USB PSU's aren't designed as compliant USB Hosts and never enumerate with an attached device and will happily pass-thru whatever current is available depending on the design of whatever is attached.
The resistor in parallel with the resistor and LED is an old trick, I've seen it used a few times for charging batteries in various equipments from my time working maintenance at the local hospital.
Never checked how those springcontacts worked. A lot simpler than i expected. This is one of those products were a bit more thought into the components, without any higher cost, would make it a good product.
@@rogierius The standard battery holder springs tend to act as induction loops (like your stove). This heavy L shape plate & "spring" is designed to accept multiple battery sizes and avoid heating.
They usually have red and green in parallel, but green LED has higher forward voltage drop and lights up only when the current going into the battery drops low. They either connect such an indicator in parallel with the cell, or through a transistor, or control it via some IC.
After watching some of your videos, I decided to try simple kits (or suites, as they call it); and initially I didn't feel good about those with SMD components, but I decided that if you said trying will help learning, one should try and see for themselves, right? After a very brief period, I came to a conclusion that if you solder manually and use lead-based solder with a low melting point, you can do and undo like 0805 or 0603, or SOT-23 quite easily, even with a «traditional» soldering iron. Since then, I don't fear SMD that much. Thank you a lot, again! SMD components are also cheaper and more compact. ^_^
@@jimmybrad156 I prefer 0805 ans 0603, since they fit right across the edges of the contact pads around the holes. And I chose to tombstone several 0805 resistors on one board - only because I decided it will fit even better this way.
11:47 “a very very long time” is between eight and nine days. Adding here since I did the math. 2000mAh / 9mA = 222.22 hours (9.2 days) 2000mAh / 10mA = 200 hours (8.3 days)
Maybe the first resistors was a voltage divider, so you don't push something like 4 volts into a 1.2V cell, but you can easily measure things, or calculate.
The other issue with letting batteries sit at a higher current is the rapid expulsion of electrolyte, when they go bang, cos someone tried charging a battery on the wrong supply and soiled themselves when said battery went pop... :P
The Schoppky Diode isnt neccesary anymore since the LEDs prevent reverse discharging as well now that there are no resistors parralel to the LEDs, right?
Just got a BT-C3100; not bad for the price, but it trickles my LSD eneloops after charging whether I like it or not. It should give the option to disable trickle charging.
If you dont mind spending a little bit of cash, I really like the Nitecore battery chargers. they have a much longer spring contact so its capable of charging AA, AAA, and 18650 batteries. I think I charged a slightly larger battery cell than the 18650 for one vape I had, but I dont recall whats its number is. The nitecore has 2 and 4 battery bay options and the one I have has a nice lcd screen for showing charge rate and battery voltage and estimated charge level of 0 to 4 bars
By using the LED's as the only current path it effectively adds a diode for each cell as well, making a fully charged cell not able to "charge" the other cells when inserted. All charge must come from the supply.
12:14 How come your Topnik RF800 is yellowish brown? I use that stuff as well (bought a 1 liter bottle for around €20) but it's pretty much colourless. It's great flux, albeit very thin.
Cud try shorting data connection on the usb plug but may allow 2amp if mains adapter is capable otherwise it be 500ma standard 1amp if that cable was any good 😅 Good idea for trickle charger tho👍
Anyone who wants a good multipurpose and multifunction charger just get a BT-C3100 or newer and you won't have to solder, modify, or reverse engineer anything. I use it for testing battery capacities and topping Ni-MH and Li-ion daily.
Can we convert this to top-up disposable salvaged 3.7v nominal cells from nebulized glycerol devices, using a recharge pcb circuit from one of the same type of devices that have recharge capability? There would be no additional components, and If the cells are charged in parallel, it may also be possible to recover some over-discharged cells when some good cells are used too. I imagine little slugs of Dowel, sporting conductive aluminium tape coats to allow charging of the various lengths of cells found in devices nowadays, considering the shrinkflation going on, both in the included cells, but also the smaller fluid active ingredient containers I have noted since 2023 rolled around. In Portsmouth, I harvest about 4-6 devices daily and 95% have viable cells, and at least 15% are rechargeable devices these days. Yesterday I found one that delivers CBD infusion with terpenes, and not derivatives of Nicotiana tabaci. I wonder how safe those are?
I bought the same ceramic tipped tweezers when I tried surface mount witchcraft, then realised I'm not a witch when it took 45 minutes to solder 6 resistors. Bollocks to that, I'll stick with through hole.
Great Video. Also Clive, not sure if you've seen, but Phillips have released their "Ultra Efficient" LED range here in the UK, they look suspiciously like Dubai Lamps. Argos sell them as do Amazon, any chance you can take a look?
Clive, why don't you do a video on this? Please do! I thought about modifying the cheap one like this that holds 3 cells. Instead of 3 in parallel, change them to 3 in series, so it would take maybe 50 mA total. The idea was to charge them using a small 5V solar panel, and leave them in a window, constantly trickle charging. Whenever a cell was needed, just pull it out and it will *always* be fully charged. Yes, I thought about the empty cell holder would prevent the remaining cells from being charged. There could be more than one solution to this. One is to connect two 1N4003 rectifier diodes in series across each cell holder, so if the voltage is greater than 1.2V it will bypass around the cell. It might need a third Schottky diode in series to make the voltage 1.5V. or it might be better to use the LEDs on the charger, and a resistor in parallel. Another solution if you don't want the diodes inside is to cut a length of 1/2" or 13mm wood dowel to the length of a AA cell, drill holes in the ends and screw small sheet metal screws in. Then connect the diodes across the screws. Mark the ends plus and minus and now you have a dummy battery that will pass current to the remaining cells. The only downside is that it's something that might be misplaced if it's left out most of the time. The idea is to make a few of these that will keep the dozen or more Ni-MH cells that I have, that will always be trickle charged using solar cells.
Charger in series will be much more complicated and expensive compared to parallel for removable battery. For example you will need more complicated circuit like BMS that will balance the voltage of batteries and additional solar panel for much higher voltage and buck circuit to stabilize the output voltage. I took this into consideration when designing solar light for my night light. Instead of using series connection that will requires me to add additonal solar panel, I simply design them in parallel then boost out the output to 12volt using boost converter. By doing that, I save money on additional solar panel as well as BMS. Why additional solar panel? Because solar panel output is variable throughout the day. You need higher voltage for reliable charging operation.
i have a cheapo one like that, its series 'as is', clive reviewed one some years back, circuit is not surprisingly rather nasty and relies partially on the resistance of the copper covered aluminium cable to limit the current 😁 current 'regulator' plus indicator is in the usb plug
You gotta work with surface mount? I don't think so. Surface mount is for the convenience of automated assembly machines, among other things. Besides that, I've been scrapping through-hole stuff for decades, and have more parts than I'll ever use. No reason I can see why a leaded resistor couldn't be tack-soldered on to those pads..
I can see Clive making a video in 5 years which shows that they've watched this and changed their design accordingly!
@@Okurka. screws cost money, i bet they will evolve to a snap together or plastic welded case
@@frogz which will we get to see, the one, the only, the vice of knowledge 😁👍
@@Okurka. 😆🤣🤣
Not Amazon
@@Okurka. They'll make 2 versions (1) for us mere mortals that will be impossible to open. (2) a Big Clive version that opens instantly upon arrival, so he can re-engineer their poor design.
Hahaha. Take out 6 components, add 1 and make the whole thing better. Great work.
❤Top end
Don't need to add the extra diode, or remove the pair of low value resistors tho' - with just the 18 ohm resistors removed, the LEDs will block the reverse current path.
I dreaded working with SMD components for a long time. Partly because they're so tiny and my hands are a bit shaky, but also because it meant I'd have to buy a whole lot more components. But then I saw a few projects on the Interwebs that I wanted to build, but they were all SMD. So I bit the bullet and ordered the boards and parts, and gave it a go.
To my surprise, it wasn't nearly as difficult as I thought. It didn't take long to get used to the tiny components, even with my unsteady hands. I even built one of Rasteri's weeCee tiny PCs, which required aligning 1.25mm twin row SMD headers within a fraction of a mm on four sides to fit the processor module.
Now I've designed my own projects that use SMD parts, designed the boards got them manufactured and everything. I've even printed and etched my own home made boards using the toner transfer method. Basically the only reason I'd go for through hole over SMD is if I wanted to use a specific through hole part (potentiometer, header pins, specific IC that I already had in through hole version), or if I wanted the circuit to look vintage (I'm currently designing a clock that uses a vintage VFD display, housed in a wood and acrylic case that shows off both the VFD and the PCB).
you don't have to replace the 5.1 ohms with a diode if you cut out the 18 ohm resistors, because the reverse breakdown of the LED's will be higher than the battery voltage so the LED's will block current from flowing back into the charger and discharging the cells.
That solering tip looks like a elephant foot for smd soldering. Never the less, you do a great job Clive. I am a fan forever!
Your NiMh trickle charger was one of the first projects I did getting back into electronics this last year. I use portable radios pretty heavily in my day to day and having a set of batteries ready to go at all times is really convenient. Thanks for doing what you do!
I've been waiting for this video since I bought a bunch of these dirt cheap chargers sometime last year. Thanks Clive.
I was taught electronics when I educated as a Radio TV Repair tech in the late 90s, and SMD was just a side notice.. Got my certificate and there was no work so I went into telecoms instead.
Been there in various jobs since then, until recently when I started working in an electronics factory and Oh sweet lord this stuff is tiny.. My glasses need glasses for some of the stuff :D
What I learned pretty early though, is get yourself a syringe of flux paste, and just jab that on there before you solder the component down, and also a sharper tip helps. The flux will really help spreading the heat, and the sharp tip will make it less messy.
That beefy charge lead probably contains at least 4 strands of wire 😂
I should have done a strand count.
Certainly more insulation than wire
ESD safe. 😂_
Aluminium-Chineseum strands…!
@@primech-128bit Any ESD will just vaporize the wire!
Thank you for another great video Clive, have a nice day and be well everyone
What a lovely follow up! Just last weekend I was thinking about building your previous trickle charger… but instead I just ordered one of these and will just remove the resistor. Thanks as always for the entertaining and educational watch!
When digital point and shoot cameras used AA batteries, customers were often impatient and wanted their batteries to charge fast !! ... there were a lot of 'Fast Chargers' sold, and I am sure they Nuked the poor NiMH cells ... I tried to sell a slower charger and a spare set of cells, but not everybody could be taught ;)
Can confirm. I might or might not own a charger that charges AA Nimh cells at 8 amps
I can recall Dave @EEVblog showcasing and investigating a fast charger. IIRC, 4A per cell, or even more, since it is said NiMH can withstand it when done right.
Photographers aren't really known for their intellect or practical skills, so it's no surprise the general public exposed to technology would fail just as professional and amateur photographers would.
@@sigmasquadleader what an interesting opinion based on facts. Thank you!
@@sigmasquadleader photography slander!
I guess the Schottky diode is belt and suspenders, because the "D" in "LED" is for "diode"; the current should only go in one direction through either.
It was to allow for a future parallel resistor addition.
I'm glad you brought up the point that the modified charger was intended to "top off" charged batteries. Basically the idea is to provide just enough current to overcome the cells internal resistance. That's actually called maintenance charging. I designed a 12.6v gel cell charger based on a 7815 series regulator that provides it's output based on the state of the battery. The charging current will be 1 amp when the battery is discharged and will taper off to about 8 ma at full charge. I chose the 8 ma value based on the data sheet for the battery. The charger and battery are in an emergency lighting system I built almost 10 years ago. The battery has lived well beyond it's natural life thanks to maintenance charging.
With regards to surface mount components, I would recommend getting a microscope to assist in placement especially for the 0805 and 0603 parts. I have a Mustool microscope that has it's own display and can magnify up to 600x. It wasn't that expensive- under $50 USD (41 GBP) on Amazon. As a radio amateur I receive the ARRL's QST magazine and a couple of years back they ran an article about using a PC cam as an alternate to a microscope. I tried it and it's doable but it is cumbersome and the magnification is limited. Solder paste is a much better alternative to fluxed solid solder as a dab will hold the part in place until you put pressure on it with tweezers. Also you get better control of the amount of solder on the pad. As to the type of tweezers the ceramic tipped ones are ok for passive components but not so good for actives such as MMICs where they might be subject to static damage. For that reason I have a grounded mat on my bench and use conductive tweezers when I'm working with actives. My workspace is a scaled down version of what I used to use back before I retired.
Finally, a schottky diode would have been my first choice since it has a forward voltage drop of about .1v as opposed to .6v for a standard PN junction diode. At 40ma the diode will dissipate only about 4mw. Later.
I really enjoy these cheap electronics teardowns. I've integrated cheap circuits into prototypes.
Clive, you made my day, I also defied using smd´s for years😂
Being an electronician since 1990... love your videos, you´re the best. 73´s.
I'm glad you mentioned the potential resistance of the USB cable. I'm also glad you mentioned reverse discharging because thats exactly what my TOMO M4 18650 power bank does that i got in 2019, so after charging 18650s with it if i dont plan on using the power bank i started removing them to stop that from happening.
Would very much like to see you do a dedicated video on how to reverse engineer a circuit board, from analysing the board to producing a schematic diagram.
It could also be turned into a handy power supply if you were looking for easy battery swaps.
im so glad im ultra near sighted. ive never needed a magnify glass since my eyes have a focal distance of 1.5 inches. in electronics class i was the only one able to do smd chips and ics without a microscope. so the teachers had to debate how to grade me since i had a advantage over all the other students.
My eyesight is the same way. I think my main concern if I got into electronics would just be protecting my eyes when working with tools at such close distances.
Being near sighted myself I have always had an advantage when working with small parts but take it from me when you get down to 0402 pitch and smaller parts you will need a microscope. The 01005 parts are not much bigger than a grain of sand.
Clive, I appreciate the recommendation on the ceramic tweezers. I grabbed some a while back after you mentioned them in another video, and they're great! They work nicely for hot air soldering of SMD stuff, too. Mine use black ceramic, supposedly ESD-safe, but I don't know if I trust that.
I would assume that the current draw had been limited to 500mA, which is the default limit for USB in the absence of shorted data lines, weird resistor combinations, or current negotiation.
there is no 'negotiation', is just a straight resistive current limit circuit, similar to most mains powered nicad/nimh chargers although one i have is more like the previous 'rougher' one, relying on the resistance of the transformer secondary wire to limit current !! you could even use a small bulb as current limiter, i've done a few times, for this a 6v 0.04a in each channel would do nicely , although not easy to find, 0.06a ones bit easier
The original USB spec was 100 mA (the pre-negotiated value) and 500 mA (the post negotiated value). The problem with that is that SOMETHING had to be able to limit the currents, and that semiconductor was $$$. Most of the Asian-supplied PCs were focused on low cost, so they omitted the current-limiting circuitry to save money. You often had the PC's raw 5V supply wired directly to the VBUS leads on the USB ports. In time, most PC guys threw up their hands and said "why bother?" and current was no longer limited. Now you have little 5V 1A and 2A wall warts that have no real current limiting to them.
I recall long ago when the PC guys inquired of Apple what it would cost to add Apple's Firewire ports on their machines. Apple's reply was $1/port. They were outraged, saying that a USB port's cost was about 1/4th of that. Apple then tried to backpeddle and lower the licensing price, but the damage was done. How many PCs did you see with Firewire ports (before Apple killed Firewire)? My point being that PC manufacturers are extremely cost-conscious.
Was excited for this, I ordered from eBay what I thought was the same charger, but I got something with a slightly different PCB on it. PCB has a model number "MQ B-04". Traces are slightly different two 1.1 or 1 ohm coming off positive, the resistors seem swapped 22ohm in series with led and 150 going to positive contact. Resistor groupings on the board is different from your example, where resistors outside the first ones on the positive side input are placed around each positive battery terminal and led. Interesting with the differences between your example, and the one I got from eBay.
I got one from AliExpress and expected the same. The one I got had the exact schematic as Clive drew on the previous video (one R parallel with an R and an LED). Different PCB layout and values though (1k in series with the LED and parallel to a 24R). I removed the 24R and now I wonder if using a 1k and LED in series with the cell even charges it at all. There is current flowing because the LEDs light up (quite well, actually)
That bottle of flux looks like my urine sample I gave to the doctor today.
Have you checked to see if it's suitable for soldering ?although if it is I'm not sure that you could stand the stench.😏
I wear an old ww2 mask when using it. Come back after a day and the joint is corroded. Gives it an antique finish and Tom cats around. That way the project also gets a cat scan at the same time. Win win all around.
@@Netties8266 Ok, so urine is fine, however let's not use it all of the time. 👍😏
that is funny that you bring out a NIMH charger video again.
I recently made a charger using one of your videos. Only things that I changed was USB-C compatible with the 5.1k resistors and I made one bay fast(er) charging with a lower resistor value.
With shipping and making only one, it still came to about the same price as a cheap charger on amazon.
6:28 If you snipped out the 20 ohm resistors the LEDs would act as diodes and stop the discharge anyway wouldn’t they?
Yet another undocumented benefit: You can use it to balance cells which are to be used in series in an applience by just letting them in there after charging, and disconnect only the USB plug. After a few days a quick boost by topping them up, and they should be balanced.
I use Nitecore chargers...single, dual & quad...for my batteries...Eneloop AA & AAA...plus Samsung 18650's.
They work great and have not failed to charge nor have they overcharged to date.
Let's do this come on ❤❤
my nitecore charger has a ton of coilwhine tho so much so I only pull it out when I really need to
Back in the days then I was young and naive I "hacked" one of those spring loaded chargers, basically threw out all the circuitry and just added a connector to hook it to a RC battery charger. I needed to charge 4 eneloop at a time (for Tamiya mini4wd models). Turns out the springs can't bear a 2A charge, they get super hot and melt. Lesson learned!
The schottky diode is not so needed, because the LEDs also are in series with the batteries, unless you do not trust them to block the back flow. And in your drawing, you did not cross out the two 5Ω1 resistors
Saw the notification and I was like "oh this is going to be fun"!
Rite Big Dude, Neat little hack. I was using my ceramic tweezers the other day and thought, wonder if Clive still uses his as I haven't seen them for a while! Love mine so thanks for pointing them out. TFS, GB :)
Delightful. Good to see that surface mount is not so scary, and a nice tool tip about the tweezers at the end. I have actually built a 3 board version of the Simple NiMH battery charger (with PCB files) Big Clive showed us how to make. 👍🙂👍
Many useful tips (as usual). Thanks!
Eneloop batteries are my favorite lasting long and being reliable this charger looks very cheaply made lol
By the way, they sell 8W rechargeable soldering irons based on a similar to EVOD devices design and 510 screw-on soldering pieces (those you showcased before). They aren't very powerful and don't last much off of full charge; yet, they can save you in the field / during a power outage.
Moreover, they started to sell like more powerful soldering pieces with a set of changeable tips and spare heating elements, and bigger announced heating power, which could make them a better solutions for owners of more powerful battery mods. Have you tried these ones yet? I'm asking because even these eight-watts things are not as bad as I expected, and if you ever happen to get yourself the newer version, it'd be quite interesting to hear your review.
I have made a couple of videos about the vape based soldering irons.
all these weirdos telling me i need tweezers and a magnifying lens and a tiny soldering tip meanwhile you're out here rawdogging it with a standard tip and just wiping them off. well, guess i learned something today.
I converted a GP 'overnight' charger for 2x2 cells into a 4x1 cells trickle charger. Mainly because the unit in its original shape could not charge 1 or 3 cells, but also because it slightly warmed up the cells when using it as a trickle charger.
The diode at 6:28 should be in series, not in parallel to the 2 resistors. Reverse current will still flow through the 2 parallel resistors. As others have said if the 18 ohm resistors are removed the extra diode isn't needed at all as the LEDs will do the job.
I should have scribbled over the resistors in the schematic. I was just showing where it would go in the circuit to replace them.
Just the everyday kind of project I find very interesting.
As someone who did the same a few years ago, I've enjoyed watching you come to terms with surface mount over the past few years.
❤❤❤
It's *amazing* , how you recognise with your knowledge a faulty/not ideal product, analyse the manufacturer's mistake(s) and improve the product to your needs with just some touches with the soldering iron and one available component out of the box! 😃👍
Clive is a gem.
@@jkobain Yesss! 😃👍
@@u.e.u.e. he taught me a lot, while simply doing things he himself enjoys and talking whatever he likes. The way he presents knowledge and technicalities is just priceless and easy.
I'm just feeling awkward and humble now.
I was going to mention it will do its best at revitalizing «dead» NiMH cells your smart chargers won't agree to recognize, and it will recover them in the safest manner possible.
But you said it right away.
I'd think the LED's would prevent discharge of the cells after removing the 18 ohm resistors. So the hack could be done with even less effort.
My first thought about the big and little resistor in parallel is that the design was meant to be used with one or the other depending on if you need extra dissipation or can go with one size of resistor. Someone just decided to populate both in the end and maybe double the value to end up with the 2.something ohms.
for nicd and nimh that circuitry is not bad at all .
in the 80s often the dc from the power supply could just go to the cells and that was fine for charging nicd and nimh.
today's lithium even the lifepo4 and lto variants require more advanced circuitry than a simple resistor to limit current.
Nice hack, thanks.
Ghhaaaaahhhh! I hate SMC. Inappropriately small. You are a master Mr. Clive!
The schottky diode is actually superfluous, the LED’s will provide reverse protection on their own. Solder bridge the schottky, you’ll get a slight bump in charge current to boot.
Gotta like NiMH for being less fussy and a bit tougher than Lithium cells.
Also for being the correct voltage for all our gadgets 👍
_Mostly_ for being compatible with devices intended for alkaline batteries. 👍
If the charging current is no too large, the excess energy on overcharged NiMh battery will be dissipated out as heat. Not easy to explose.
No I don't, keep your 1.2 volts if ur lucky, next someone gonna tell me benefits of those horrible nicads
@@mos8541 NiCd -> high-power performance at very low temperature. Sorry, couldn't resist. XD
I do have some NiMH AA and AAA cells. For instance, I've been using NiMH AA ones in my wireless mouse every day for more than ten years already; and I can't really tell how many days or weeks it takes to discharge one cell. The mouse has a boost circuit in it, so it drains the cell quicker, but doesn't require two (thus neither weighs significantly more, nor falls to using two AAAs).
Those cells I bought before switching to this wireless mouse are still with me, and I honestly can't really even tell which of them all were bought a bit later; maybe only by date codes, or measuring their capacity degradation. I used to think NiCd cells are better for low-current applications: I've been told they have smaller self-discharge current. But, again, after more than ten years of using NiMH cells every day, I can't complain.
Initially, I didn't really like Lithium cells when they started appearing here and there, I was even more dumb and incompetent than I am now (surprisingly, it was possible!), plus they weren't as good as they can be today. Nowadays, I still like NiMH cells, already like Lithium cells (recently found three discarded POD units, one of them is rechargeable and supports cartridges with e-liquid and mesh heater), but my observations show that NiCd cells are leaving us: they suffer from memory effects similar to those of NiMH ones, they chemically degrade like faster, and their capacity per weight and per volume haven't been improved lately by the manufacturers.
I may be wrong (and I often tend to be), but this is my personal experience.
a skill i have yet to master, it's fun to play around on old phone chargers
I'll share my tip for surface mount components, you need a stick of paper glue and a cocktail stick.
Put a tiny bit of glue in the middle of the component with one end of the stick & place it on the pcb. Then using the other end apply a little pressure to keep it there while you solder it.
USB 2.0 can only support 500mA anyway so I think it makes sense that the charger does not go above that.
And some dirty wall adapters can't even supply this much, eh.
ninaryguru Hey What's up
That's if the current to be passed from a 'Host' has been negotiated via protocol with an attached device. Most USB PSU's aren't designed as compliant USB Hosts and never enumerate with an attached device and will happily pass-thru whatever current is available depending on the design of whatever is attached.
They totally saw your video and made a revision 😂
The resistor in parallel with the resistor and LED is an old trick, I've seen it used a few times for charging batteries in various equipments from my time working maintenance at the local hospital.
Yeah, I’ve seen that arrangement used in domestic and industrial Ni-Cad chargers from the 1980s onwards.
That USB Buck Booster sure looks interesting.
Links to things like your flux and tweezers would be handy please. They might earn you a few pennies too if they're Amazon or eBay affiliate links.
very simple circuit, i understood everything !
Never checked how those springcontacts worked. A lot simpler than i expected.
This is one of those products were a bit more thought into the components, without any higher cost, would make it a good product.
Those L shaped sliding contacts are the only way to do reliable charging. A simple spring always heats up and fails.
Noob here, but the L-shape battery holding mechanism has a spring as well. Or am I missing something obvious here?
@@rogierius The standard battery holder springs tend to act as induction loops (like your stove).
This heavy L shape plate & "spring" is designed to accept multiple battery sizes and avoid heating.
I "Rescue" cells with an alligator clip and another cell in parallel for a few seconds. Just enough to trick my smart charger. 😂
I have a NiZn charger that's pretty advanced, has some form of monitoring or a fake way with dual-color LEDs
They usually have red and green in parallel, but green LED has higher forward voltage drop and lights up only when the current going into the battery drops low. They either connect such an indicator in parallel with the cell, or through a transistor, or control it via some IC.
I would rather use surface mount than through hole. Much easier to work with once you have a system.
Ahh Clive turns something I can't understand into something I can't understand.
I feel relieved from my own stupidity.
After watching some of your videos, I decided to try simple kits (or suites, as they call it); and initially I didn't feel good about those with SMD components, but I decided that if you said trying will help learning, one should try and see for themselves, right? After a very brief period, I came to a conclusion that if you solder manually and use lead-based solder with a low melting point, you can do and undo like 0805 or 0603, or SOT-23 quite easily, even with a «traditional» soldering iron. Since then, I don't fear SMD that much. Thank you a lot, again!
SMD components are also cheaper and more compact. ^_^
Janus Kobain hey What's up bro
I get 1206 size SMD components where I can; manages to fit on 0.1" (2.54mm) veroboard hole spacing not too bad.
@@jimmybrad156 I prefer 0805 ans 0603, since they fit right across the edges of the contact pads around the holes. And I chose to tombstone several 0805 resistors on one board - only because I decided it will fit even better this way.
@@jkobain What I really meant is that 1206's are a little easier to keep a hold of lol
@@jimmybrad156 and the numbers are bigger to read, lol. ;D
Although caps are blank anyway…
11:47 “a very very long time” is between eight and nine days. Adding here since I did the math.
2000mAh / 9mA = 222.22 hours (9.2 days)
2000mAh / 10mA = 200 hours (8.3 days)
Maybe the first resistors was a voltage divider, so you don't push something like 4 volts into a 1.2V cell, but you can easily measure things, or calculate.
Whoever designed that cardboard box was clearly a doctor who fan...
Rightyo? Trying to sound cool... Nice work there master Clive
Content free comment to drive engagement for my favorite channels
The other issue with letting batteries sit at a higher current is the rapid expulsion of electrolyte, when they go bang, cos someone tried charging a battery on the wrong supply and soiled themselves when said battery went pop... :P
The Schoppky Diode isnt neccesary anymore since the LEDs prevent reverse discharging as well now that there are no resistors parralel to the LEDs, right?
Just got a BT-C3100; not bad for the price, but it trickles my LSD eneloops after charging whether I like it or not. It should give the option to disable trickle charging.
Clive, thanks for the regular reminders to never fly in a Chinese built aircraft!
If you dont mind spending a little bit of cash, I really like the Nitecore battery chargers. they have a much longer spring contact so its capable of charging AA, AAA, and 18650 batteries. I think I charged a slightly larger battery cell than the 18650 for one vape I had, but I dont recall whats its number is.
The nitecore has 2 and 4 battery bay options and the one I have has a nice lcd screen for showing charge rate and battery voltage and estimated charge level of 0 to 4 bars
By using the LED's as the only current path it effectively adds a diode for each cell as well, making a fully charged cell not able to "charge" the other cells when inserted. All charge must come from the supply.
Hence, changing the resistors for the scottky diode was unnecessary.
So the back feed is actually a secret feature to drain the batteries for storage 😮
Nice mod , thankyou for sharing
12:14
How come your Topnik RF800 is yellowish brown?
I use that stuff as well (bought a 1 liter bottle for around €20) but it's pretty much colourless.
It's great flux, albeit very thin.
It's possibly been diluted a bit further.
How about adding a switch to change between trickle charging and fast charging? Could be useful, not too difficult to build.
Cool. Great improvement. Are they available from Big Clive Industrial Electronics Corporation yet? I'll take 2. Keep working. Good luck! 👍
6:28 Why did you remove the two resistors on the input side and replace it with a diode, when the LEDs are diodes and will do the same thing?
It's with adding other parallel resistors for higher current in mind.
The diode on the input side is to prevent discharging when the USB isn't powered (but still plugged in).
The LEDs (diodes that emit light) will serve the "same" purpose of preventing reverse current on the batteries.
@@luisfhm007 Ah, yes. ISWYM.
Cud try shorting data connection on the usb plug but may allow 2amp if mains adapter is capable otherwise it be 500ma standard 1amp if that cable was any good 😅
Good idea for trickle charger tho👍
I would be tempted to remove the 5.11 ohm resistors to reduce the trickle current!
Anyone who wants a good multipurpose and multifunction charger just get a BT-C3100 or newer and you won't have to solder, modify, or reverse engineer anything. I use it for testing battery capacities and topping Ni-MH and Li-ion daily.
Can we convert this to top-up disposable salvaged 3.7v nominal cells from nebulized glycerol devices, using a recharge pcb circuit from one of the same type of devices that have recharge capability? There would be no additional components, and If the cells are charged in parallel, it may also be possible to recover some over-discharged cells when some good cells are used too. I imagine little slugs of Dowel, sporting conductive aluminium tape coats to allow charging of the various lengths of cells found in devices nowadays, considering the shrinkflation going on, both in the included cells, but also the smaller fluid active ingredient containers I have noted since 2023 rolled around. In Portsmouth, I harvest about 4-6 devices daily and 95% have viable cells, and at least 15% are rechargeable devices these days. Yesterday I found one that delivers CBD infusion with terpenes, and not derivatives of Nicotiana tabaci. I wonder how safe those are?
It’s not rocket science but you do make it clear.
I think the design has changed already, I bought one - 8 resistors, no diode and drawing 12mA per cell 🙂 They are quick to copy
I bought the same ceramic tipped tweezers when I tried surface mount witchcraft, then realised I'm not a witch when it took 45 minutes to solder 6 resistors. Bollocks to that, I'll stick with through hole.
USB2 spec only allows 500mA current draw. Probably that's why it's limited to 450
The leds also prevent cells back feeding to each other now
Wooooh! Ceramic tweezers! Nice!
And very cheap on eBay too.
Thanks for sharing
This was a fun video.
I think they stole your design there Clive!
Great Video. Also Clive, not sure if you've seen, but Phillips have released their "Ultra Efficient" LED range here in the UK, they look suspiciously like Dubai Lamps. Argos sell them as do Amazon, any chance you can take a look?
Already reverse engineered one a while ago.
Clive, why don't you do a video on this? Please do!
I thought about modifying the cheap one like this that holds 3 cells. Instead of 3 in parallel, change them to 3 in series, so it would take maybe 50 mA total. The idea was to charge them using a small 5V solar panel, and leave them in a window, constantly trickle charging. Whenever a cell was needed, just pull it out and it will *always* be fully charged.
Yes, I thought about the empty cell holder would prevent the remaining cells from being charged. There could be more than one solution to this. One is to connect two 1N4003 rectifier diodes in series across each cell holder, so if the voltage is greater than 1.2V it will bypass around the cell. It might need a third Schottky diode in series to make the voltage 1.5V. or it might be better to use the LEDs on the charger, and a resistor in parallel.
Another solution if you don't want the diodes inside is to cut a length of 1/2" or 13mm wood dowel to the length of a AA cell, drill holes in the ends and screw small sheet metal screws in. Then connect the diodes across the screws. Mark the ends plus and minus and now you have a dummy battery that will pass current to the remaining cells. The only downside is that it's something that might be misplaced if it's left out most of the time.
The idea is to make a few of these that will keep the dozen or more Ni-MH cells that I have, that will always be trickle charged using solar cells.
Charger in series will be much more complicated and expensive compared to parallel for removable battery. For example you will need more complicated circuit like BMS that will balance the voltage of batteries and additional solar panel for much higher voltage and buck circuit to stabilize the output voltage.
I took this into consideration when designing solar light for my night light. Instead of using series connection that will requires me to add additonal solar panel, I simply design them in parallel then boost out the output to 12volt using boost converter. By doing that, I save money on additional solar panel as well as BMS.
Why additional solar panel? Because solar panel output is variable throughout the day. You need higher voltage for reliable charging operation.
i have a cheapo one like that, its series 'as is', clive reviewed one some years back, circuit is not surprisingly rather nasty and relies partially on the resistance of the copper covered aluminium cable to limit the current 😁 current 'regulator' plus indicator is in the usb plug
How much reverse leakage through those LEDs? Possibly use them instead of adding a diode?
You gotta work with surface mount? I don't think so. Surface mount is for the convenience of automated assembly machines, among other things. Besides that, I've been scrapping through-hole stuff for decades, and have more parts than I'll ever use. No reason I can see why a leaded resistor couldn't be tack-soldered on to those pads..