Crappy lead-acid LED lamp with brilliantly simple circuitry.
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- Опубліковано 5 лис 2018
- This version of the now classic "intelligent emergency lamp" has the most minimalist circuitry seen yet, and what appears to be an SLA (Sealed Lead Acid) battery. In one area it has cut cost a bit too much and in another area it is fiendishly clever in using just a single transistor in its active circuitry.
I just had to take the lead acid battery apart to see what was inside. Mainly lead and acid apparently. Quite a lot of lead too - I guess they have to get rid of all that lead somewhere.
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That's the cutest little lead acid battery...
volvo09 I wonder if they are cheap enough to couple up a hundred or so for my car?
I have some 2 volts that would possibly spin the starter....they double as boat anchors when not powering stuff.
For starting those tiny Chinese cars...
I can't believe they are that small!
In the 90s a friend had a Walkman with sla.
I guess any diode can be an LED (briefly) given the right circumstances.
I was just about to say that. Thanks ElectroBOOM!
Well it was a diode and it emitted light so absolutely correct, not quite conventional or intended...🙄but typically Clive
Almost anything will light up briefly if enough current is applied!
Giovani Tapini even Clive...
There is, of course, the classical N.E.D., the Noise Emitting Diode, closely akin to the Write-Only Memory.
Manufacturer: "how do we get rid of this old lead waste?"
Engineer: "hold my beer"
I can't imagine a more pleasant design than little plastic cases filled with sulphuric acid above my head in small cheap devices that may fail with heat. Awesome!
AGM batteries don't leak.
@@----.__ I know they are sealed but when they fail they do. I am the proud owner of a failed AGM battery that was in a golf buggy and I can promise you it leaked the magic juice.
@@CozzyKnowsBest Ouch, that's unfortunate. We use them in our designs for heavy workclass ROVs due to them being non-serviceable and functional in any orientation. We do buy disproportionately expensive ones though due to having to meet hazardous area standards though, I now shudder to think of what is sold at the consumer end.
On another note, "Came House", my goodness. It's strange how footage like that can be both awe inspiring and saddening, I can almost hear the laughter of a family playing in the garden yet it's juxtaposed by the dilapidated state of the estate. Your videos are amazing.
I think you're being sarcastic, but tiny lead acid batteries in my light bulbs actually does turn me on.
Also a failed or overcharged lead-acid battery can emit hydrogen sulphide which is a poisonous and explosive gas. I once left a LA battery charging downstairs when I went to bed and in the early hours was woken up by an awful smell, which I blamed on the cat. When I got up for breakfast the smell was worse and the copper pipes in the kitchen had turned black. Only then did I realise that I'd a narrow escape.
so, don't leave a LA battery charging overnight, charge it in a ventilated area, don't charge it in the house, use an intelligent battery charger.
Clive invents the Light-emitting Zener. The LEZ.
LEZ-BO
@@BenjaminEsposti The BO stands for Booms Orgiastically.
He's invented light-emitting batteries, light emitting power supplies, and well, he's invented light-emitting everything.
More like lava emitting zener. If they don't explode, they will go molten glass instead. And then explode. :)
2:09 That'd be the SED or "smoke-emitting diode"
I used to work in the battery charger industry. The work used to involve the fitment and maintenance of battery charging equipment in electricity power stations and substations. Sometime in the 1980's the National Grid and regional electricity companies started specifying SLA cells, because they were promised by the battery suppliers a lifespan of 25 years and zero maintenance.
Unfortunately for them, they fell foul of a characteristic of SLA's that you probably didn't know. The 'float' charging voltage of an SLA (the voltage applied to the cells when they are fully charged), is dependent on temperature. Most modern industrial battery chargers are equipped with remote temperature probes, which should be situated at the battery location. The probes then send a signal back the charge controller, which reduces the charging voltage when the ambient temperature increases. In a lot of cases, new SLA's were installed with old chargers, with no temperature compensation. If the location of the battery / charger was somewhere nice and toasty warm, the cells would fail, sometimes in as little as 5 or 6 years.
That being said, I can see a very short life for that little 2 cell battery. Not only is it being overcharged in the first place, I'm guessing it will get pretty hot situated behind those LED's.
The forward drop of a diode also goes down with temperature, and it's nearly the same tempco as a lead acid battery. I've been using a string of silicon diodes as a float voltage regulator here on the off-grid homesite for decades. LA batteries last a looooong time when you do that. Now, as to the tempco of those forward biased leds, dunno, but I'd bet it's similar. So, likely more clever than realized here.
@pmailkeey Well, given that Lead Acid batteries DO have a tempco, and the slightly different chemistries act a little differently (maintenance-proof PbCa vs normal) and some are more easily harmed by electrolysis (AGM), that's not a question with a single answer....
Most of my work is with deep cycle batteries, like the ~ 2300 ah 24v nominal that run my homestead (with solar and backup generators etc) or just act as a secondary UPS for the ham rig and a couple important homestead lan of things computers. Those tend to follow the curves given by Trace/Xantrex/ or the battery manufs pretty closely. batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures has some info. If you know a battery is fully charged, it ought to be set to some voltage that makes it draw only a tiny fraction of C to just sit there...maybe 50ma for a 100ah battery or so. Which would usually work out around 13.5 v at around room temp for a trolling deep cycle "12v" battery, a PbCa one will float higher happily (14.1 at least, those don't gas as easily but also don't live through deep cycling), and you shouldn't really push any continuous current into an AGM battery.
As mentioned below, my big ones (a few tons...) DO have catalytic caps that recombine any H2 and O2 into water if I gas them a little. Pro solar charge controllers do this according to a schedule.
What is the forward drop of the M7 Diode (I think that's what the schematic says)? The larger the drop of that diode, the lower the charging voltage will be. It could be a diode chosen for high forward drop.
The Mrs has likened big Clive to Bob Ross, the Bob Ross of electrical engineering.
Plenty of "happy little accidents", for sure.
A small but interesting point of chemistry: Sealed lead acid batteries don't use polyester (which would be decomposed by the sulfuric acid) or any other type of plastic to absorb the acid. The only plastic involved is the battery casing, which is typically polypropylene or high density polyethylene, since they are structurally strong and resistant to all acids.
There are two types of sealed lead acid battery: Absorbed glass mat (AGM) cells or gel cells. In the AGM type, the space between the lead plates is filled with fine glass fibre matting, similar to glass wool for cheaper cells or can be the properly woven matting for high end, ultra-durable cells. The glass fibre soaks up the acid and holds it in place.
Gel cells use about 5% by weight of fumed silica (silicon dioxide) which is an especially fine powder, made by incinerating silicon tetrachloride in a 1500 degree (or hotter) flame. This has an absurdly high surface area which makes it an excellent gelling agent, and its inert nature means it can be used to gel concentrated acids, even rocket grade nitric acid if necessary.
The two types do have advantages and disadvantages. Gel cells contain more acid for their size, giving them a higher amp-hour rating, since the charge capacity of a lead-acid cell is based on how much sulfuric acid it can hold. However, gel cells can still suffer from plate-warping (if the gel is allowed to dry out) and bridging crystal growth (resulting from excessive discharge) in the same way as ordinary wet cells.
This is where AGM cells have the major advantage. They contain less acid (so have lower charge capacity) because more of their volume is filled with glass fibre. However, the glass fibre matting holds the lead plates apart and prevents plate-warping, even if the cell is completely dried out. The glass matting also prevents (or at least inhibits) bridging crystal growth, meaning that AGM cells can be subjected to much deeper discharge cycles without damage.
If the cell is completely dried out, why would plate warping be of any concern? That cell, and the whole battery, is ready for the recycling bin regardless of how straight the plates are.
The usual cause of plate warping IS drying out of the cell, and it doesn't have to be completely dry for that to happen. The liquid component of the battery (the electrolyte) is 35% sulfuric acid solution in water, regardless of whether that is gelled with silica, absorbed into glass fibre, or neither. The sulfuric acid is converted into lead sulfate when the battery is discharged, the reverse happens on charging, so very little acid is completely lost unless the battery case has a leak.
The water is another matter: Some evaporates through imperfect seals, but most water loss is due to overcharging, which causes electrolysis to happen inside the battery, producing hydrogen and oxygen gases. Sometimes, batteries installed in airtight compartments have catalysts fitted inside which recombine these gases back into water, preventing water loss, pressure buildup and risk of explosion. This is however expensive, so in most cases it is easier to just periodically check electrolyte levels and top up batteries with distilled water.
If this is not done, then eventually the electrolyte level can drop enough for the plates to partially dry out. That subjects the plates to temperature variation and uneven sulfate buildup, both of which can bend or warp them. This is usually irreversible and results in the battery being binned, or preferably recycled. The exception is with AGM batteries, where the glass fibre holds the plates in place and stops them bending or warping. If it is mainly the water that has been lost, the battery can just be topped up with more water. If both the acid and the water have been lost somehow, then fresh 35% sulfuric acid can be added. Either way, the battery will then work again.
@@lloydevans2900 Ok, if the cell is dry and you're going to attempt to add water, it would be good if the plates weren't warped. Got it. I've never tried adding water to a gell cell or SLA because until recently I did not know that it was possible (but apparently once you break the cover off, the battery is no longer an SLA, just an LA, and will leak if not kept upright).
@@lloydevans2900 Also I've read in several different places that in SLAs the hydrogen and oxygen produced during an overcharge can recombine if the pressure inside the battery does not rise so much that the 3-5PSI vent opens. I have not however read how this is supposed to happen.
I did wonder how polyester fibre would hold up to acid as soon as I mentioned it. The traditional glass fibre does make sense.
battery is an AGM (absorbed glass mat) lead acid. Spill proof and handles vibrations better than most batteries....
I can't hear the word rectifier without picturing a guy with a uni brow explode for some reason...
¡BOOM!
Or the phrase, "Full Wave Bridge"....
You mean rectum fryer?
3 phase rectifier; "FULLER BRIDGE RECTIFIER!!!11"
Safety squints on. I really like those glass mat batteries. Such a simple thing but I find they're much more robust in my possession and on my bike than a regular flooded cell.
Yeah, I have a 12n12 sealed lead-acid on my Harley...nothing big, no electric starter...they last 5-6 years or more...even less $$ than wet cells...Yuasa.
Turning a zener into an LED nice one Clive :) Regards to Sir
Great, Clive is back to his precise, easy to understand way of speaking. Now I finally understand what made the "intelligent" emergency lamp from 6 days ago special
I only watch this because his voice is calming and it's interesting even tho I don't know shit
Careful! The more you watch, the more you'll learn.
+Divine -3- How did Clive constipate you? Careful how much you eat - you'll explode.
Divine -3-: That makes you a cool chick, and you will pick stuff up :)
I would recommend a channel called MrCarlsonsLab, it's similar but more oriented towards repair of vintage electronics. Beautiful old tech, SUPER high production value, and the guy has a great voice too. A lot of his fans have no interest in electronics, it's just a great show, like this one.
try...Stefan Gotteswinter…..
@@Shaun.Stephens hahaha.. Fuck you lol it was a typo 😂
Sealed LA batteries sometimes have a catalyst foam somewhere in its package to burn the generated O2 and H2 back to water. If you over charge one of these batteries, they will just heat up and dissipate the extra power dumping in them,
The true good sealed ones must have that, whereas this is the "valve regulated" type that just let's gassed escape? Or do they all have valve vents? I've only pulled apart a few agm batteries (those common backup batteries) and they only had the rubber nipples. I haven't come across a high quality agm battery yet.
They chose lead acid even though it is technically more expensive per cell, because a lithium ion cell would get overcharged and go pop here. Lead acid is more forgiving. Basically, they went with a technically more expensive cell to have a cheaper overall product that isn't burning houses down.
It is also possible they did have a lot of extra lead acid batteries they got for cheap at the market, but I think that is putting the horse before the wagon.
Love stuff like this. Cheap as fuck, made to a price, potentially lethal, yet designed by a genius.
As has been said it's an AGM (absorbant glass matt) lead acid. My understanding (from automotive applications ) was that all AGMs are sealed as a key part of the chemjcal process is recombination of the electrolyte, once it is lost then the cells cease to function, partial loss will obviously result in impaired performance. This is why the automotive batteries are often referred to as VRLA or valve regulated lead acid, the valve just being essentially a safety pressure relief valve if the cell is overcharged. We were also told by the manhfacturer to not exceed 14.8v which is 2.47v per cell, indeed some were left on charge over a christmas period with the charging setup we used for regular lead acid batteries (3A constant current with a 16v ceiling). That killed them well & truly, the cells had an open circuit voltage but absoloutely zero capacity. Good old lead acid, much maligned but generally benign & very recyclable!
This is exactly what my lamp circuitry was like... but mine uses 18650 cell without protection instead. That SLA battery is very common in cheap Chinese flashlight or mosquito racket because they're cheap and don't require protection to charge, they usually just get charged by a capacitor dropper like that but I haven't seen one venting or oozing out electrolytes though.
All rechargeable lithium batteries require protection!
Just because the chinese cheapos might not always have it does not meant that that is a good thing ;)
@@Ultrazaubererger oh sorry, i mean the SLA battery is common in cheap Chinese stuffs
nimh is still allowed for backup lighting systems, because i guess the manufacturers are too lazy to develop a bit of extra circuitry, they too can be continous trickle charge
@Jusb1066 NiMH is super durable and stable and it doesn't need fancy charging circuitry, the only cons of it are fairly low capacity but I think it's fine for that purpose
@@pierreuntel1970 yep, but i also had a brain fart, nicad is sill allowed for lighting, and that is how they are still sold in the UK
This is a VERY CLEVER circuit! Colin Mitchell would be proud!
I wonder they'll use super capacitors soon.
But I want that tiny lead acid battery, didn't knew they made them that small.
Super caps would need to come down in price and increase in capacity before they would be viable.
They are mainly used on cheep flashlight and mosquito swatters. 4v measured, that means internal part is 2*2v
RIGHT!? I want to put that battery in everything. My cell phone. My remote controlled car. My vibrator. My left shoe.
I got one from a cheaptastic charging LED flashlight, it has contacts that pop out and plug into the socket, served me and my mom very well for a long time
Clive's analysis is right on: The stink is hydrogen sulfide, generated when you overcharge a lead-acid battery.
There was a case not long ago where a mechanic put a 12V battery into a BMW with a 24V system. The battery generated so much H2S that the driver was killed.
Glowing zener diodes and lead-acid LEDs! Red-hot brilliant! ....and an egg battery!! Ni, ni, ni!!
Kinda cool to see an AGM lead acid battery in something like this... Although I wouldn't want one because of the overcharging issue.
Reverse engineerded schematics explained, that is when I love you Clive. Thanks
Another great video! And the comments are equally enlightening.
The mini lead acid is kind of cool.
The most sh*t thing about the whole idea is, when it's on battery mode the light output is so low that it's basically useless.
There probably are a bunch of Chinese that graduate and often can't escape China or can't work for a major corporation, so they just have to make weird little circuits like this for some BS company that wants to sell stuff in cheap stores and on ebay.
It's not useless, it is an emergency light, made to last longer, we use it in my area, when the elec goes down, the light needs to last the whole night, and this works perfectly, not sure why not giving them the credit for such simple and smart engineering.
Give the credit where the credit is due.
That has to be the cutest little SLA battery I have ever seen, I've not seen one that small!! :D
I remember making a lead acid battery in school that looked similar to this. We separated two sheets of lead with a piece of absorbent paper, rolled them up, and then soaked everything in sulfuric acid. We wore no gloves or eye protection, which I’m afraid might date how long ago this was done. The cell could then be charged by connecting it to a DC power supply. We used the cell yo propel a little cart with a DC motor on it.
0 days since last chemical spill. Nice job.
:-)
I loved seeing the Pliers of Persuasion open that battery. :-)
Hi Clive, this would have been an ideal use for the manic arm. When testing the cap you could have clamped the battery in one end and the other to the vice of knowledge as a base.
"tongs ya bass" laughed so much I sprayed tea on my monitor.......
Your knowledge of electronics is astonishing 👍 wow
My dog farted just as the cell cracked open; it really added to the experience
Lol "tongs ya bas" ...unheard in 50 years, until now.. 😂
Clive, I don’t believe I’ve ever seen a Light Emitting Zener (LEZ?) diode before. Congratulations on the new discovery! :-)
Who had "I may have to pause while I go in deeper" on BigClive innuendo bingo?
Thanks Clive.
Thank you Clive. Very cool!
Really interested in those small lead acid batterys!
absorbent glass mat battery, some are set up "sealed" with reservoirs to gather the outgas and let it go back into the battery
SuperAWaC yep, a small AGM. Not super cheap, generally. NiMH might’ve been an alternative.
Your voice sounds nice in my headphones
When ever the vice of knowledge come out , it's a good day ! :)
when you talked about having a bit of an incident and skidmarks, I spat my tea all over the keyboard.. yes.. I'm THAT mature..
I got a 8 of these bulbs. All of them went bang in less than weeks. Good thing my house didn't get on fire.
I got a tennis-racket-like bug zapper with one of those LA batteries. I replaced it with an 18650 (protected). It seems to work perfectly and charges as it should. I never had anything with one of those LA batteries last even a year before the battery was dead.
"Slight skidmark here, I had a bit on an incident" @ 1:45
Excellent analysis
I found a similar battery/capacitive dropper circuit in a cheap chinese torch once, it definitely was surprising how few components are needed and probably is the reason why they keep making those.
Really interesting piece bigyin..
Bigclive, I found a battery like that in my electric bug zapper. It was dead so I took the battery apart and it was indeed a SLA battery. Voltage is 4 volts like the battery here. I have a pack of four 1.2 volt AAA batteries that I made and I think i need to take off a cell because the zapper won't charge. the adapter says 5 volts but has closer to 4.7 volts.
Is there any chance you could do a kit-assembly video on one of those hyper-cheap Chinese DIY single-channel oscilloscopes with the little TFT display? They are primarily through-hole with the SMT chips already attached. I am considering one just to do the most basic work with TTL-level DC power supplies and micro PHI2 timing and the like. I would be very interested to see your opinion on one.
Julian Ilett did a multi-video build of a cheapy scope a few years back. Might be worth checking that!
@@charliedobbie8916 I don't know that videographer, but I'll have a look for his channel--many thanks!
ua-cam.com/users/results?search_query=julian+ilett+oscilloscope
Not an awful lot of point in building them yourself though unless you just want the satisfaction, they're the same price pre-completed.
@@paulsengupta971 Have to say I disagree there. As a hobbyist, practice is always *extremely* valuable. At the end of the day do any of us really need to do _any_ electronics at all unless we work as electrical engineers?
"It's somehow managed to be both brilliant and shit" Same, Clive
Regarding cheap vs cheaper products from Chinese sellers, I've experienced being shipped cheaper versions on my second order from the same seller. First was a LED headlamp where the angle adjustment of the cheaper copy was so bad it would tilt down to point at your nose from the slightest head movement. Second was an analog video capture card where the cheaper one was lacking a lot of decoupling capacitors and a dedicated audio ADC. Makes me think some sellers intentionally ship the good version to gain your trust on your first order in the hope that you will place a larger second order where they can sell the cheaper stuff for the same price.
The little rubber cap you removed is a relief valve. If the pressure inside the cell gets too high, the cap inflates and allows gas to vent out the sides. That's the "valve" in a "VRLA" battery which is another name for the majority of SLA and Gell batteries. VRLA batteries are able to tolerate a certain amount of overcharge without damage or loss of electrolyte. (Some include a catalyst to speed recombination of hydrogen and oxygen, allowing a higher tolerance to overcharge.) Wikipedia has a well written explanation: en.wikipedia.org/wiki/VRLA_battery
Interesting. I wasn't aware that SLA style batteries had the ability to recombine the gasses internally like NiMhs. One notable sentence reads "Sustained charging at 2.7 V per cell will damage the cells" which is unfortunate, since that's the voltage they went up to. I was looking at another device last night that is basically a capacitive dropper charging an SLA battery directly with absolutely no voltage cap.
@@bigclivedotcom that's the voltage where gassing begins. The point is that gassing is only harmful if occurs at a rate faster than recombination can keep up. If charging current is low, the gas recombines into water and is recycled indefinitely. In other words, the battery IS the voltage regulator. Quite brilliant I think!
When your Zener diode becomes an LED...
Emitting the wrong flavour of light though :)
I have an item you might be interested in looking at, it nearly set fire to my home.
It's an extension lead sold by B&Q .it's burnt out and the plastic casing has melted/burned through.
I would be happy to post it to you if it is something you would be interested in taking apart to find out how dangerous it might have been?
And when that second LED from the bottom fails open circuit the only thing limiting the charge voltage is luck or maybe that zener loading the dropper?
Got a link to the interesting ones? Would the addition of a Zener circuit around the battery help?
What’s the forward voltage of the diode in the battery charging circuit? Is that enough to take the voltage down low enough for the lead acid battery?
bigclive i find your videos facinating , even though for 99% of the time i am totally at a loss as to what you are explaining , is there any beginners courses in electronics you could recommend for someone like me . Love the videos though
The fiber in the battery is to keep the led close to the electrodes, so you can discharge it without the led going so far away form the electrodes that it won't get back onto them when the battery is recharged. The fiber is the usual difference between a battery to start a car and a battery to run a alp lift/genie/electric boat etcetera.
Thanks for all the hard work reverse engineering this Clive, wish I had your technical expertise. Find these videos very interesting. Also need to give a huge thankyou for providing the link to your videos in the patreon information which saves guys like me who watch via a tablet trying to log into patreon to get the video which takes far too much effort for me as all my passwords are generated for me using keepass so are long and complex so I only log in to patreon when I'm at my computer.
Nice, thanks for sharing😀👍
'Tongs ya Bas' Haven't heard that in a very long time!
Me neither, but it's good Clive is keeping it alive!
What does it mean? When did Clive say it?
It is a phrase used by Glasgow gang the Tongs. Summary on wikipaedia en.m.wikipedia.org/wiki/Tongland_(gang_area)
At 1min 55sec
Did you do a film about ‘reactive power’ v ‘watts’. Metering? Or can you explain it again please....sounds fascinating.
Beautiful videos
"amazing and shit at the same time" is basically my life
I would think that they used some hydrophilic salt or organic compound to hold the battery moist.
The battery has also a crude deep drain protection with the diodes.
Also the lead-plates are very crude. They could have easily doubled the capacity and halved the material price if they plated iron meshes with the lead. Old cheap lead-acid batteries where done that way. (they break down fast if the plating is to thin.)
There was a diode on your schematic labeled M7. Might that cause enough drop to get the charge from 6 volts down to 4.7?
An M7 is a surface mount diode that, as far as I understand, is the same as a regular 1N4007, so it should't have a voltage drop more than the usual .6 volts or so.
Two would be enough
790i
i dont trust the diode forward drop, its not always the 0.6 , on low loads i had 0.2 around dropped only...
@@PsiQ I was just thinking I wished they'd included a couple of extra series diodes, the rest of the circuit's sufficiently awesome to make it quite a shame :( - Oh, and you always include a 'bonus load' resistor drawing 25ma or so, just to guarantee against the half dozen miliamps @ V - 0.2n..
Psi Q If you measured 0.2V drop with a food under low loads that was much more likely to have been a Schottky died than an ordinary silicon rectifier diode. Schottky diodes are used extensively where one want minimal voltage drop, such as in switching power supplies. They just don’t have the same high breakdown voltages as seen in typical silicon rectifiers - if they did they would be darn near everywhere - but where you don’t need high breakdown voltage ratings the Schottky diodes waste much less energy, and voltage, to voltage drop across the diode.
Hi Clive, maybe the diode between the the battery and the LEDs (used to define the 6volts for charging) will drop a couple of volts and protect the wee sacrificial lead-acid battery.
ie, it could be two or three diodes in series, or the LEDs may drop a significant voltage less than the 6V you estimated. {I wish I could type, that's why I'm answering my partial comment here.}
how many watts is the outputs of full and stanby.? ie one on mains, and one on the battery?
Is it possible they are relying on the voltage drop under load to prevent the battery from overcharging? I'm thinking they have it at 6 volt for the fullest and fastest charge, and then as the battery approaches full, the current drops, and basically you'd have to leave the light on for days for it to accept enough current to bring it to the full 6 volts and cook off all the water? I know from experience that 12 volt lead acid batteries on an 8 amp charger take current at 14 and then 15 volts for a very long time, hours, before the charger ever reaches the roughly 16~17 open circuit voltage.
foxy likes the SLA ! will be looking for some !
Here you go, fluffball: www.aliexpress.com/w/wholesale-lead-acid.html?SearchText=lead+acid&maxPrice=10&CatId=1009
Interestingly, buying the entire lamp (example: www.ebay.com/sch/i.html?_nkw=smart+led+emergency, go for the cheapest) sees you spending about the same per battery as in those aliexpress listings AND gets you a supply of components and lamp housings to play with for free. Fun!
Am I the only person who's thinking of getting one of these then surreptitiously slipping a bit of foil into my mouth to freak out a coworker on the next electrical job?
You wouldn't need the foil. Just your tongue will make it light.
I was thinking that it might give your bare tongue a bit of an unwelcome tingle. It's just a pity that I'm done with that part of the renovation.
The fellow I was working with knows nothing about electricity and was a little freaked out when the lights he had switched off started to glow when I was changing a fixture in a different part of the basement.
If it smells eggy, that suggests hydrogen sulphide, which as far as I know shouldn't be present in a lead/sulphuric acid cell. I wonder if it's a sign of the mistreatment of the battery having caused some unwanted chemical reactions already?
H2S is produced when a cell is overcharged.
@@SinsBird Case closed
Most lead-acid batteries begin to smell farty when you get them opened up (or they exploded), or a lot of acid splashes out of them. It's faint at first, but if it just came off of a charger, and it's hot, ooh it's like Satan just shat in your shop.
Keep in mind, that you can smell very small concentrations. At higher concentrations your receptors kind of get numb, so once you don't smell the stuff anymore, that's when it gets interesting/dangerous ;-)
@@SigEpBlue Lol!
Have onne of this cheap emergency lights but fades after 2 hours, can I add another battery in parallel to increase the time? or can I replace the lead-acid with a 28650 lithium cell with BMS?
If that battery is what it appears to be, it's an AGM battery (Absorbed Glass Matrix) and is the favoured type for use in mobility scooters and the like. It may appear cheaper, but it costs more than a basic SLA battery, and as you saw, even when you crush the living daylights out of it, it still does not leak (so to speak). They're usually slightly lower Ah capacity and don't charge or discharge quite as readily, but they are considered to be safer. I have a pair of 50Ah AGM batteries that I plan to investigate. They appear to have dehydrated and sucked in the sides of the casing. I want to see if they can be rehydrated and made to work again.
Mobility batteries tend not to live very long, and it's usually the same old story of the acid having dried up, so, I've just bought some "Aqua Distillata" (Distilled water) with the plan to rehydrate these batteries, but, because of the glass matrix, it's likely to be a slow process over several days to fully rehydrate them, and even then, no certainty that they will live again.
That zener at 2:10 , an infra-red light-emitting diode in the unusal black-body mode of operation.
I was waiting for the hiss and bang!
Did you measure the excessive charge voltage before or after blowing the zener diode? It *was* limiting the DC voltags on that circuit...
It was in series with a resistor to discharge the electrolytic capacitor when the unit is turned off so the LEDs go out quickly and also to provide a slight clamping load against current leakage that could make the lamp keep glowing from mains power when it's turned off. The zener was to give that circuit a higher active voltage to avoid false triggering of the lamp via its low sense voltage.
"I might have to pause momentarily as I go in deeper"
I'd imagine they chose lead-acid because lithium-ion would go pop in this _economy_ circuit.
Clive, if you have a load with a dreadful power factor like this, is it possible to use a cap across the mains input to shift the phase variance so far that it actually comes back into phase?
Not so easy, since this is already effectively a cap across the mains, which is part of the issue. The real problem is the current waveform, which tends to peak near the middle of the sinewave.
Somewhere in China: An EE is being toasted by his colleagues for getting a BigClive seal of approval.
I like how the UA-cam trying to sell me LED bulbs before the video. I'm still using Philips cfl Sl bulbs from the 80s
They did it in order to save the charging circuitry for the Lithium batteries, plus the Li battery. Quite clever indeed
Alarm systems still use lead acid batteries, namely gel lead acid as a backup battery.
Wireless detectors use typically 3v lithium. Cr2 or cr123 batteries, lasting 2-3years typically.
Big Clive, I can’t believe you didn’t go ahead and replace that SLA with a protected lithium cell... You would have to repair the zener diode too though..
My grandmother had an emergency lamp socket that had a radioactive materials warning sticker on it, any knowledge about those? I was always curious as it seemed too small to be able to power an incandescent bulb.
Probably used Tritium for radioluminescence.
A Fluke! That was long overdue. Now if Clive will start using an 87-V then I can die happy.
A very old Fluke. It was my first pro meter.
2:11 So you added an extra LED. I'd call that a success!
I saw that mini lead batteries in the zapping mosquito tennis rackets.
When i needed to change them i used 2 AA ni-mh.
I guess the reason they used a SLA is that a Lithium cell would not have tolerated the charging abuse, and would probably release all of its smoke and much of its fire as well. Wonderful example of minimalist design, but I cant help wondering if it would be more cost effective just to have more components and fewer LEDs for the same light output?
I've got a lamp like that, I've managed to get the value of the zener at 18 volts, they might just put on what ever they have in hand
The lead acid batteries can deal much better being fully charged the whole time. Lithium batterys will rapidly die when held up to 4.2 V permanently. As a rule of thumb the lithium battery will live double the time by reducing the full charge voltage by 0.1 V.
Did you ever do a HOPI tear down..? I really fancy getting one just for a play. Are they any good..???
It seems fine. I really should take it apart sometime. John Ward uses a unit with a colour LCD display which doesn't flicker on camera like mine does.
Hey Clive!
I have a Cree light bulb that catastrophically failed and all the bits inside have melted. I can email it to you for a proper autopsy if you're interested. (I can send photos in advance if you want. I haven't opened it, but you can see all the melted bits through the bulb)
thrillscience I'd pay money to see you Email a physical device to Clive! Lol!