Inside some cheap lithium cell chargers. With schematic.
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- Опубликовано: 26 май 2016
- These units are available suspiciously cheaply from eBay and are designed to charge a wide range of lithium cells using a long spring loaded battery contact. The charge current is variable according to the cell voltage, with the current progressively reducing as the cell charges.
The circuitry is basically a super-minimalist flyback switcher powering a generic lithium charger chip which seems to have the useful facility of detecting the cell voltage and swapping the charge contact polarity accordingly.
Rather predictably, track isolation is minimal and the transformers internal separation is an unknown variable. I'd suggest not touching the contacts of these units while they're plugged in.
If you enjoy the videos on this channel you can help support it with a dollar for coffee, cookies and non-compliant chargers at / bigclive 
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I just love the way you reverse engineer this stuff. It's so interesting to see it all logically pulled apart like this. Thanks.
I have 3 of the single cell chargers. They work a treat keep my fleet of salvage laptop cells topped up for my fleet of cheap LED torches. Thank you for the explanation.
Don't leave them unattended
So easy to use, you just unbox it and throw it into the trash! 👍
Your videos help keep me sane. Thanks for doing what you do and please keep it up!
I have several of those chargers, they came with every laser pointer I purchased.
Great video Clive. Glad u chose to do videos. I enjoy your teardowns and have learnt a lot from you. Thanks for your time
hi clive thankyou for your time and tear downs, very interesting
It would be interesting to see a teardown of one of those liitokala chargers, they seem pretty advanced for the price.
Great! Now that I've cheaped out on Chinese lithium batteries, time to throw them in cheap chargers! Nothing could possibly go wrong like blowing my own face off or anything.
I have had one of those blasted things laying around in our Motor Home now for a couple of years, just in case I can't find my good charger. Well we got back to South Dakota, land of snow, wind and hail, and when I off loaded the rig, I neglected to bring in the good charger As time went by, I found myself in need of a charger, so it was back to the rig, which is parked in our back yard. I could not find my good charger right off, so I grabbed that little one, that came with some flash light I think, and I brought it in the house. On the way in, I noticed a rattle coming from the charger so before plugging her in, I took her apart. I found a small transistor laying loose inside. I went over that blasted circuit board for over an hour but could not find a place where it should be soldered in. So I put in a couple of cells (it was a two banger) and plugged her into the wall. After about an hour, I checked on how things were going. I pulled it out of the wall outlet, and both cells were very HOT, enough that it actually raised a blister on one finger. After dropping it and allowing it to cool, I found that neither battery had any charge any more, before charging one was at about 3 volts, the other showed no charge. Ok so now the charger lay in pieces in my parts box, and the blister on my finger is doing OK
I've never really had much interest in electronics. But, you explain things so clearly and simply, that even a hamster-brain like me feels that I could have been a sparky/ techy, if I had chosen to do so. Ha.
Got one of the single chargers for use with 18650 batteries. Looks identical to the one shown. And it is very slow, taking over 24 hours to charge a 2200mAh 18650 cell from about 50%. Seems dubiously safe as well. Time to toss it and upgrade! Thanks for the review!
the american version of that first charger has a connector for the flip-out plug that protrudes through the circuit board. the metal strip is only held in place with a couple tiny dabs of melted plastic, so when it inevitably breaks it'll either short out the plug or connect the exposed metal clip directly to 115v ac.
I'm not sure if its just my procrastination, but I find all of your videos entertaining, even though i have no clue what you're talking about for the most part. :D
Actually the chargers are not bad! If you have checked DiodeGoneWild's videos, the problem is in the POWER SUPPLY. The chip however is quite good. I don't know what's the voltage output of the power supply from your charger, but the charging current is proportional to the voltage input. I'm takling about HotChip HT3582D.
I have two of those chargers (the one with 2 slots), and I took the chip out and tested on breadboard. It does terminate the cell at 4.2 volts. But at 5 volts input, an empty 18650 cell only charge at 150 mA. With 7 volts input though, it charges at 380mA! When nearly full, it charges at 120 mA oppose to 40mA-ish like yours. I was able to translate the datasheet, and the chips can take up to 8 volts, with max charging current of ~400 mA. So it's not bad, I'm planning to place the two chips into a single circuit so that each cell has it's own IC (and safely charge two cells at a time). The only thing I disappoint of is that it allows feedback from the cell to the chip, and does not let charge the battery when a schottky diode is added.
So if you people happen to have a similar charger, get rid of the crappy power supply and turn it into USB power like how DiodeGoneWild did. Or better yet, rebuild the entire crappy circuit, and change the voltage input to regulated 7.5 volts. It doesn't take a while since the charging circuit is totally dead simple to build with only 2~5 external components.
Aside from the circuitry doing ac=>dc, this could be quickly refitted with a TP4056 board to at least repurpose the holder. Especially because it's easily modified to use different charging currents. Fits well with one of those cheap usb current/voltage/capacity monitors.
I always giggle seeing "ultrafire" on a battery, especially when the capacity is so much larger than it should be.
The cheap chargers work very well ATTENDED. Most chargers are off these little chargers are on the money. A reference point for Hobby chargers. Those Alarm buzzers are notoriously off. BUT USABLE AS ALARM. USING HOBBY CHARGER W NO BMS
Great teardown, thank you very much for your explanations!
i always learn from your videos. Thanks.
lol that is the EXACT charger that came with my non-Ebay flashlight. Which, of course, only turns green when you jiggle it.
Get a small piece of double-sided .5mm copper clad. Solder a wire on each side and you've got something that can easily be used to measure the current through batteries inside their holders. Add a shunt resistor for current monitoring on an oscilloscope for battery powered circuits. That much more useful than the probe-poking ;-)
at least the first one has a charge circuit , the one i got (that looks identical) is very very simple with just a transistor a diode an led and possibly a capacitive dropper
That's the exact charger that came with an Epipe I purchases off Aliexpress. I didn't use it much but it took forever to even "top off" a battery.
It's very easy to see why that transistor went bang. Also when it fails it will go BANG! if the first diode doesn't fail first. Also that 400V 1uf has more potential to go bang than you think if there's significant transient spikes on the mains supply. It's a right and proper little banger this thing 😂
I have gotten a few chargers free with some flashlights I bought on ebay, but none of mine even had an IC in them, just a couple of transistors. I just tossed them in the bin, I wouldn't trust using them.
If you are going to charge lithium batteries, it's worth it to spend $15 - $20 to get a decent charger that is actually safe to use.
This is supposed to be a charger with EU plug, but it cannot be inserted into EU socket! The reason is that EU sockets are not flat, but have "edge", and prongs of this charger are not long enough to reach connectors in EU sockets, or at least they don't hold properly and are very unsafe. I ended up opening it, removing the prongs, and soldering regular EU cable to it's PCB.
Greetings from Australia. Just wondering if you can do a pull apart check on a touch switch modules the ones used on lamps where you just touch any metal part and it turns on some of them in thee stages , because they work of mains wondering how dangerous are they.
Interesting to see the schematic for these cheap chargers. I did also test some chargers looking similar, but not exactly the same. They where not great chargers. The single slot charged to 4.35 volt (I could not read the chip number, it was in Chinese), the dual slot was a without ICs, but could both do NiMH and LiIon.
I had a CFL go bang just the other day. was a transistor on the board.
Smashing video clive :-D.
It is quite minimal, with a better transistor and an input fuse/ptc im sure it will work fine.
Im ignoring all the filtering and knee jerk reactions to basic circuits, even complex well designed ones go pop for no reason at all.
Dave jones of eevblog would go into orbit with disgust and panic lol.
I have one that destroyed it's self and a battery it was charging. It was plugged in to a serge protector with a built in 10 amp breaker. It was on for about 30 minutes and then the breaker on the bar tripped, I went to check it and the plastic on the charger and the battery were melting! I yanked it out of the wall and put it outside on concrete in case it went boom. After it cooled it was unrecognizable as a charger, the battery was bulging and dead.
theres another kind of charger on ebay almost identical to the single cell charger in this vid. it doesnt claim reverse polarity detection and it has extra terminals as if for a 9V PP3 either side of the charging slot but theyre not connected to anything. however it stays almost totally cool in use whereas the transistor in the one in this vid gets very warm/hot
Mine went KBOOM last night, but what seems to have failed is the capacitor next to the transformer.
Went looking for these chargers on ebay, with the plan to rip the transformer off the board, and power it from a proper DC supply.
Couldn't find one the same though, though the IC is available from the usual suspects.
was there any overcharge protection in the charger? I only wonder as about 90% of the lithiums sold on EBAY claim to have the over/undercharge protection, but just don't, including some I was sent with a charger.
Have you any views on the safety (lack thereof) of those cheap "Ultra Fire" 18650 batteries that are freely and cheaply available on Ebay?
I got a small flashlight from cub scouts a long time ago, and it came with a 14500 battery and this charger. Eventually, the charger refused to charge the battery, so I tried a AA battery, and when it didn't work, I was like, "what the...?" It disappeared some time ago.
I love watching this a can't explain why as I'm not to smart with electrics lol but I'm learning
is there any books that shows pics of the blueprint diagram so I can learn what all the lines and triangles...I am a fast learner with mechanical part of stuff but electrical I don't have enough confidence to deal with dwino or resistors...I don't get how the damb chip really works
got the first one just a couple days ago with a violet laser and a dubious ultra-fire 18650 from banggood. charger went straight into the bin. right decision i guess.
One of these days you are going to get a shock from one of these Chinese products resulting in these awesome videos stopping. I hope that day doesn't ever come. I really enjoy them.
This is why I make sure I got a good proper charger, a Xtar VC2, and always buy proper 18650 batteries from a credible source and not cheap rewraps.
I'm just a hobbyist but I've been trying to figure out how a lithium ion charger chip (like a TP4056) actually drops the voltage coming in from a 5V USB supply to 4.2V. I'm not having any luck finding an internal circuit diagram for something like this (not that it'd be much use to an amateur like me anyway). The datasheet for the 4056 says it can take a maximum of 8V as an input. If it's not switching the supply to buck the voltage with a choke, is it simply a linear voltage regulator or something?
It uses a transistor operating in its linear region (not fully turned on) like a resistor. That limits the current it can charge at, as it dissipates the voltage difference as heat. If it gets too hot it will regulate the current down.
That's helpful Clive, thank you. Your explanations always turn the seemingly complex trivial. Once again I've underestimated the utility of the transistor. I think some further practical experimentation is called for...
Transistors can do amazing things! :D
Actually this charger can't be used in regular grounded eu sockets, because the legs are too short. I think they can be used in the russian eu non-grounded sockets, but can be used with any adapter as well.
I had the small charger, it exploded and blew the fuse. Opened it up and saw that one leg of a component had´nt been cut off completely on the back side and was bent over and touching an other component.
I got a charger that looks like the first one in your video. When I put a battery in it, the led will flash red. I wanted to charge a battery, but when I put the battery in, I got quite a nasty shock when I touched a contact of the charger.
got to love those negat-ive charges
never thought I would find you here woolen :)
i like these kinds of channels
negat I've charges, no less... "chinglish" at its finest.
+Dosbomber Thought it was Engrish.
lmao
How big is the capacitor next to the small transformer? Thanks
Hey Clive do you think you will ever get some Arduinos to test?
Really old video but thought I'd mention that I have a couple chargers that look just like the single one here, but with US/120V plug. This video caused me to look at the labels more closely, and mine doesn't say anything about battery polarity, just plus and minus. But the label also says the input is 110-220V which I found surprising. I wonder if/how the output would change, if at all. Oh, and mine is only a 450mA output, not 500 like yours, so I feel cheated... :)
The current is supposed to fall as it charges... at least once it gets to the constant voltage part of the charge cycle. Up to that point should be constant current.
Hi, you gave a sneaky peek of a USB clip lithium multi charger in your video, I'd be interested to know if it's any good and whether you'd consider reviewing it? it looks handy for camera and older mobile phone batteries. Thanks in advance John.
I've had same problem with the cheap 4 cell ones they just packed up but I think the crap battery I used shorted it lol think it cudn't handle a fully discharged 18650 bin job lol ...thanks for the reverse engineering circuit👍
does it charge those gumstick batteries used in cassette tapes?
Who came here from DiodeGonewillld??
What did he do - ,mention Clive?
@@NeuronalAxon no but he makes similar content
@@franzliszt8576 agreed but plugs are different, Clive is in the UK, diodegonewhile is in Europe
I could not find the peg like multi charger on eBay. Can you say where you can get them? Thanks
That charger AND a card reader? With what thing did you get that one included, just curious. seems like a strange combination, like potato peeler and geiger counter combo, Chernobyl inspired :-)
Pyroslav x That gives me an idea for my next project. XD
A sand shovel that doubles as a coffee mug
Some of these types of single chargers have the ability to auto detect charge voltage depending on the type of cell it "sees". As an example if you place a deeply discharged Lithion cell into it, the charge will begin as if it were a NiCad. Briefly opening the contact and closing it will sometimes, given the cell enough of a charge to begin charging at the lithion voltage, so be very aware that lithion cells can go bang. Never leave these unattended. Place in a metal bucket or box if you do
I have used these to charge cells removed from dead laptop packs. Your results may vary...!! so Pay Attention !! As a side note: I have never had any cell go bang BUT there is always a first time
Craig Nehring l
This is actually quite handy, but then again, care should ALWAYS be taken when charging deeply discharged lithium cells, especially chinese made 18650s
Very nice video. I have one of these single cell chargers, I mean exactly like that one you have and I saw you having pretty decent Li-ion charging chip I decided to check if I can make mine work without AC voltage.
And it failed. I found the datasheet (in chinese, but Google helped), but after disassembling the charger I got only bunch of transistors and resistors :( It would be nice if I could power it from USB.
One more thing, my front sticker doesn't say anything about negat-ive voltage, only that is patented product.
Great minds must think in similar fashion! I just recorded a teardown video (minus the reverse engineering haha) a few days ago on the same charger as the first one (well, it is similar, not identical.) and was planning on uploading it tomorrow. Would you mind if I made an addendum to my video with a "side-by-side" - so to speak - comparison to your charger?
can it charges AA Ni-MH 1.2v?
Adding some scope images would be quite interesting
Could you possibly improve it by covering the tracks with something like molten plastic or wax? The dielectric strength of air is relatively weak so I'm thinking if it sparks it will do it through air.
I have that same charger for 2 cells on its way from Shenzhen right now.
well.. wax is flammable, so, id not try that. maybe a high level glass filled nylon would be ok, but, thats basically what a chip board is, so, may as well print a new board with larger spacing.
When i charge my battery with one battery charger it give me a red lamp and it not give me orange or green to know it charged i bought a new battery and not work to help please
I've had a few of these blow I got a more safer version by ultrafire but I still need a safer charger for the little green batteries the 15270
Negat I've? Were they typing that in chinglish on an iphone?
Did you mean extra resistor when referring to the double unit? (you said capacitor) - going by the fact you said it was was 13K and across a capacitor probably to trickle current (I know stripey capacitors are a thing).
i jest what to ask what brand of lit screwdriver do you use iv seen you use it a lot and it look like it holeds up well and i bin what to get a smal set but i didnt yet cus i what to find a good set any recommendations you whod have for low end of price and mid and high if you can help that be alsome pleas and thinks ps love your vidow thay are vay help full on difint levis
Aren't those isolation slits great?
My mother had an external HDD with a battery that has been connected to external power for almost three years, suddenly we saw that the battery had expanded and pushed the case it's in apart. So I'd think that battery is dead of course, but do you think it could run without the battery connected, or that the battery could be replaced? Haven't opened it yet to disconnect and remove the battery, but I will.
Update?
how long will it take to charge 18650 sony vtc4? i buy this kind of charger and almost 3 hours the light is still red 😅😅😅
300mA through a 1N4148?
LOL! The highest I've seen the 1N4148 rated at is 150mA ...
I'm betting the current pulses through the diode are even higher, since it's pulses and not a continuous DC current.
'....a capacitor with the value of brown orange orange' :)
Did a double take there, not gonna lie.
Well it is from China. Did a bit of a double take on that as well.
***** I have only had my hands on capacitors without color coding and I thought Clive made an error and that he meant a Resistor but now I realise I was the one making an error because there are capacitors with color coding :)
I still think he meant a resistor, since he says it's (10:48) "13k" and "across this little electrolytic".
***** oh well. I thought 'double take' meant you re-watched after I posted my comment and thought I was wrong. There's only one who knows the answer but its not important.
Can I change 1.2v battery
Thanku brother
I bought two chargers of these Chinese
I ask: It is dangerous to put the battery with the reverse polarity, I think it can cause a short circuit
I have checked that if the battery is first placed in the charger before placing it in the AC outlet, the polarity is correct ...
For the cheap price it is better to change the internal circuit for a Tp4056 and a USB connection and we have a charger with a retractable slot.
Greetings from Venezuela.
Nice
i got an old battery pack with a nearly dead cell (has maybe half it's og capacity) and i'm tempted to repurpose the electronics on a new cell
I should feel bad and outdated...
FIRST!
Although, never been this early to the new video party.
Loving the videos Clive!
and now you are a useless git, congrats.
Finally I've reached git status :P
git-scm.com/docs/git-status intentional?
Nope, but good thinking. Thats a joke I could commit to.
I want circuit charger battery3.7volt by tansistor it has one LED turn off when fully charged
I flip-flop about Chinese products, probably on a daily basis but... In the states, various workers have these "cute" phrases: "close enough for government work" "good enough for the girls I go out with" "musta been made on Friday afternoon" etc.
If you could somehow chart those sayings into values, they'd still outshine the Chinese stuff.
Notice: Tomorrow I'll change my mind ;-)
I've had 2 of these things and both of them fried when flicking the switch so I'm not gonna use one of these again knowing the damage a shorted 18650 can cause.
funny i have the same skinny Lithium charger when i first got it i was confused of front but on the back it is made by "hong Dong" which i find a little amusing.
you could convert those to usb power instead of mains power as that would be safer
I love your videos. What is a good 18650 battery charger for the US? I would like to change the batteries to 3.9 or 4.0 votes only.
I would appreciate any help, thanks.
I wish it was easy to find a simple charger that did that. You may have to use a professional programmable charger to get the lower voltage.
There are some Nitecore and LaCrosse chargers which have that facility that aren't *too* spendy IIRC - check FastTech or Banggood and the like.
why my charger it lamp doesnot work
The single cell charger I got was best - it is supposed to be able charge two 9v rechargables.
The 9v cells connections have only screws holding them on - nothing else.
c3.staticflickr.com/6/5697/30541341810_a91d223952_z.jpg
Never had a problem
Is it okay to continuously charge a button li-ion using only a resistor limiter?
I have a programmable wall plug and it doesn't seem to have a smart charge chip, only a resistor, and the battery heats up somewhat.
It's probably a NiMh cell which can be trickle charged continuously. (Green sleeve?)
bigclivedotcom It has "li ion" written on it...
I have the charger on the left and the light stays green when I try to charge a 18650 battery, any idea what's wrong and how to fix? Ty.
Sounds like the battery is not making a connection or a wire has come off inside.
What's the point of bothering to put in reverse polarity safety circuitry if there's no contact nub (i.e. you need a little nut) or better question- why do we have those nubs at all if contact can so easily be made (sometimes accidentally). Have I just answered my own question (as in the nub shows polarity)? :/
I wonder if the two cell one also says that. It's definately not reversable if they are in parallel. Someone could put them in different ways causing a short and blowing it up.
Can you give some video for repair this adapter
It would cost more to repair than buying the replacement charger. And next time you can buy a better one that won't fail again and again.
You mean extra resistor I take it, because you are talking about the color stripes. I was lost as you said it was an odd value capacitor. But I get it, none the less another crappy charger. I hate these cheap chargers.
So everyone always hates on these cheap ass chargers and batteries but has anyone actually tried to use them for a long time????
Yes - they let the smoke out at some point.
i have the single cell charger and it no joke takes a whole day to charge a 18650
"Not up to western standards" - An understatement, by Big Clive, 2016... :P
I have to admit, when it comes to lithium batteries, if they're not integrated into something, I tend to not trust them much, and even less so in chargers whose labels are far from confidence-inspiring... :S
Still, worth taking apart, never to be put together again... :P
thats the SAMe orange knife i use for work lol
Can you charge lipo battery with it.?
If it's a standard lithium cell with your charge threshold of 4.2v then it should be OK. But none of the cheap chargers are reliable or safe.
@@bigclivedotcom can lipo battery take charge up to 4.2 volt? I have the same charger as in the video.
from California U.S.A
I've got a charger that looks just like this one on the outside, but the inside is completely different, and I can't figure out how to get the spring back in place.
ok, now it's completely broken. oops.
The way the spring hooks in is not very helpful in re-assembling it. I found it best to hold the battery contact from the outside as I put the PCB back in.
hi,i have problem using this charger,i tried to charge 3.7v battery but light was green instead of red,i thought maybe my charger is some chinese shit and it will turn red when its fully charged,but after few hours still it was green light,i took battery and tried on my flashlight and its working,so...what is happening?is it possible that connection is bad,but then how i got fully charged battery if connection was bad?
Is the light still green if no battery is in the charger? If not then it may just be charging at such a low current that it takes a very long time to charge the battery. If you have a meter then I'd suggest setting it to DC voltage and making sure the output voltage with no battery isn't going above 4.2V.