Don't do this! (There's a much safer way)

this video is about how to charge a found lithium cell properly and more importantly how not to charge a found lithium cell in a recent video i've featured vapor devices that can be found lying in the gutter on the street that actually contain a rechargeable cell of decent capacity i've tested one of these cells it was spectacularly good performance and after i published that video people said oh yeah charge that myself by getting a usb lead stripping the ends and putting it straight across the lithium cell and plug it into a usb charger do not do this there are so many reasons not to do this and i'm going to demonstrate them right now by showing you what happens and what could potentially happen if you do that so here is a fairly beefy lithium uh well usb charger and i'm going to plug a analyzer into this this is a little rear deng analyzer and keep in mind you only really want to charge these cells at about 500 milliamps to one amp if you plug it into a usb power supply straight as it is two things will happen it's gone to over three amps immediately which is way too much current for that cell and more importantly the usb charger is going to try and charge this cell up to 5 volts and you must not do that it will not only potentially damage the cell and reduce the number of charge cycles you get out of it dramatically but if you over charge these cells above about 4.2 volts which is their normal safe charging level it can cause chemistry problems inside not just depleting the lifespan of the cell but it can actually make them fail and when they fail they can sometimes go short circuit inside you'll get a jet of vapor coming out the end if that vapor which is combustible light you'll end up the little flamethrower and if you've got this charger in your house um and you forget about it you might come back to a house fire just thought i'd mention that now i don't want to be alarmist here um i don't want to make it out that lithium cells are a terrible thing they're a great thing they're one of the best battery technologies but you have to treat them with respect you have to make sure you don't physically damage them and you have to make sure you don't damage the chemistry inside by over charging them so i'm going to show you some ways to charge these and uh they will be based on these little modules you can buy from ebay they're very cheap you don't just buy one of them buy a strip of them because it's actually cheaper to buy them in bulk if you go on ebay and search for tp4056 module i'll provide a link down below to a search for that then you will find sets of these available for sale there are simple ones and there are complex ones now there is another scenario with this some batteries that you might find that are salvaged from equipment do actually have a protection circuit built in in that case if you were to just slam current into these with a usb lead it will still over charge it current wise but it should actually cut off at the 4.2 volts but it's not an ideal thing to do the only thing that is limiting the current is usually the cable itself and it's not an ideal situation it's very unpredictable let me show you uh the circuit board that's in the end of this cell it uses two chips it's got the dw01 which is a special chip dedicated to protecting lithium cells and it uses a little double mosfet the reason for the double mosfet is so it can actually stop that charging when it reaches the upper level and also if you over discharge it it'll also cut it off to stop the battery being just run right into the ground there are very few support components needed with these i'm going to cover these because the same components are actually on one of these circuit boards so let's take a look at that chip in the first place the dw01a this little chip has the mosfets and if you connect the cell across it it monitors the voltage across the cell with a 100 ohm resistor and a 100 nano farad capacitor this just provides basically a bit of decoupling for any sort of noise from the load that's connected and it means that it can actually accurately monitor the voltage across that cell it also does one other thing um it has a 1k resistor here and it measures the voltage across these mosfets and if it exceeds 0.15 volts it will actually turn the mosfets off to protect itself so that's the short circuit protection that does not work when you're charging it as far as i know only when you're discharging but this thing is a sort of it's useful it will actually cut off at 4.3 volts which is above the normal 4.2 volts and it'll cut off at 2.5 volts from your discharging it is basically purely to prevent extremes from uh going too far so let's take a look at the first of these modules you can buy off ebay then i'll show you how to hook some leads up to them so you can reuse your cells lots of times i've got a little one here a little module that i've doctored up that i've been testing this is out one of these type of device and this one this cell is rated about 500 milliamp hour this particular one i've run several full charging discharge cycles at sensible currents 500 milliamps and the first one well i missed the first few cycles because it's only after i'd done it a few times i thought i should be documenting this and consistently it's gone after the first few cycles it went up to about 481 milliamp hour and over one two three four five six seven eight nine 10 11 12 13 14 15 16 17 18 19 20 21 22 plus all the previous ones so let's say 25 it's at 485 milliamp hour which is very respectable for a 500 milliamp hour cell that is well within the tolerance and it shows that you know these salvage cells have a lot of uses so here is the first of these little modules you can buy off ebay it's a fine module it doesn't have that extra layer of protection i prefer the other module that has it but let's take a look at it so we have the classic chip this is a charge control chip and it has a resistor here that sets the current most of these comes set for the maximum current which is one amp and while that's not ideal for these if you're not really comfortable with changing this resistor this tiny little surface mount resistor which uh you can also just replace it just by soldering to adjacent pads that are bigger you can just replace the quarter watt resistor if you want but ideally for compactness you'd replace it with another surface mount resistor at the moment it's one point two thousand ohms uh but if you change that to two point two thousand ohms it suits these batteries back to these little lithium cells because it will charge them at 500 milliamps and you can customize that it's a nice it means it'll take longer to charge than just the bare unit as received from ebay but it will just treat the cells a little bit better and they'll last a bit longer i should put this device down i'm not going to puff that but this chip has other tricks it shows you when it's charging it shows you when it's completed charging and it has various things if the cell voltage is too low it will start trickle charging at one tenth of the programmed current just to get it started gently it also has thermal regulation if it gets too hot it will actually cut back the current itself so the circuitry on this particular unit looks like this the usb supply comes in and it goes to the chip via a 0.4 ohm resistor which is kind of it's shown in the data sheet but many don't use that i think they're relying on the resistance of the usb leads but there's a 0.4 ohm resistor and a little local decoupling capacitor to provide stability for the chip the current is programmed with this resistor here and if you look at the data sheet for the chip let me just grab the data sheet for the chip because it's got a set of resistance values here so it goes from the default value that supplied these modules one point two thousand ohms will give one thousand milliamps or one amp output i experimented i found 2.2 000 ohms gave around about the 500 milliamps which is just in between the 4 and 580 here but if you've got really small cells you can put in up to 10k as a resistor you can actually go much higher than that but they don't really document it but that will charge a very low 130 milliamps which is ideal for really tiny cells it's a very versatile chip it's super useful things worthy of note the chip terminates charge at the end when it detects that the current you've programmed say for instance this is the as supplied from ebay it's set for the one amp because it's got a one point two thousand ohm resistor it's only when it the current tails off to 100 milliamps that the fully charged indicator will light um it's worth mentioning that if you have a 500 milliamp hour cell and you're charging at 500 milliamps then after an hour even though it takes a while for it to do the final top off after an hour it's got most of its charge you could use at that point without waiting for it to finish charging the next charger from ebay is my favorite type it adds an extra layer let's get this one out the way so it's not got a little obstruction back it has two modules it has the classic tp4 of five six this one doesn't have that serious resistor it's got the same 1.2 k one two two one two and two zeros so it's got the same one amp resistor that you can change but this has the extra advantage of having the dw01a and this mosfet now it's worth mentioning that if you look at the tiny mosfet package on this one because the circuitry measures the voltage in the vent of an overload or short circuit because a smaller mosfet will have a slightly higher resistance uh it means that it's capable of supplying less current before that over current trips this one uses a bigger one i don't know what its current rating is but generally speaking the bigger mosfet packages have a lower resistance so they will actually be able to put out a lot more current before it actually trips the over current or the short circuit protection uh i shall show you the schematic for this one and then i shall show you how to make your little charge adapter so in the case of this one it starts off exactly the same as the other without that uh resistor though that point four ohm resistor it's got the same two leds with one k resistors it's got the same programming resistor by default the one amp programming but the difference is that this one then has the protection chip as well um and that drives the mosfets and it just provides that extra it provides double overcharge protection but more importantly in this case for my applications um i run strings of leds and stuff off them and it stops it from over discharging it cuts it off at 2.5 volts instead of just letting the cell go all the way down to the bottom because if you operate the lithium cells within their voltage range of about 4.2 volts down to about 3 volts or so it just prolongs their life greatly and look at that one that i've been testing it's been getting great cycles okay now to get on to making your little adapter for this you can do two things here if you're just wanting to jump onto lithium cells you could put a couple of crocodile clips leads onto one of these modules on the battery output connection but my preference is this little arrangement here where you can put a connector in the battery and you can then use it for powering other things via this other connector with all that extra protection the advantage of this one i have used it to top up cells in devices like this when refilling them with liquids and topping the cell up it's very important that when you do that make sure you don't short anything out and get the polarity correct double check the polarity if you put this the wrong way around it may actually blow up these modules they might not be too happy about it so to make up your adapter use your favorite connector everyday is a favorite connector these are mine they're sort of little molexy type connectors um there is a name for them can't really remember is xh25 i don't think it is not sure but there is a name for these connectors i kind of like them um and make up two female connectors and one male connector the male connector is to plug into the battery because by making up with connectors it means that you can basically use it with multiple batteries in the case of this one i'd just not have a usb lead connected i would just put one of these little connectors on so i'm going to uh get the soldering iron on and i'm going to bring the bits in and i'm going to show you how to solder this up so one moment please the soldering iron is up to temperature i've brought this up closer so we can see it better so there are four connections on the output of this b plus and b minus are the battery connections and out plus and out minus are the load connections so the first thing i'm going to do is i'm going to get some juicy lead based solder it's my preferred solder and i'm going to put a little soda onto each of these pads now you could put the wires through the circuit boards i find it easier just to actually sew them directly onto the pads so let's get some soda onto these let's do this properly the soda is actually going through because those are fairly plated through-hole pads now the first connection i'm going to put on is the one that's going to the battery so following the polarity here just place your pre terminated stripped and tint connector onto their wire onto here and just flow it then get the positive and flow it on being careful not to bridge to anything in the vicinity allow to cool then this is my output connect that i'm going to be using for loads so we want to put the negative one to the out negative oh get get the solder iron in here and the out positive onto the positive connection and that is it but for one small thing i recommend putting a bit of heat shrink sleeving over this or wrapping tape because if you have this floating about in your bench there is a risk that things are going to get short-circuited okay i'm just going to get this stuff out the way i'll show you putting the heat shrink sleeving on and then we can test this we'll actually connect the battery i'll tell you what before i do that here is the battery let's get the other connector that i have handy here which is my little flying socket and i show just sorry about the swamped out fingers the lighting is really just focused on the small area here so when you're sold onto these batteries a couple of things to note don't linger too long they do have decent tabs coming off if the tabs which are very fragile snap don't try soldier onto what's left of them because it can cause problems uh the one of the tabs may be copper and one b aluminium sometimes if you remove the bit that takes the solder that has out the factory you can't actually solder onto that but just be careful also make sure that nothing can bridge onto the the little pinched seal on these because um they've got a conductive sort of metal layer of foil inside so after double checking polarity take your positive connection hopefully this will be in focus i think it's in focus and reflow that onto there then get your negative connection and we'll reflow onto the tin pad now it's important to note that these connections are not really load bearing so i would recommend wrapping a bit of captain tape or other tape over these just to actually reinforce them to give them extra strength it will just make it uh last much longer right tell you what i'm going to clear this stuff out the way and then we can test this first of all let's get the heat shrink on now the heat shrink size i use is 12.7 millimeters i think that's a shrunk size once it's been shrunk down it just seems a good choice if in doubt do i do is it was this a good idea is this actually going to go through here yeah it's going to go through there and just by a few different sizes it just it's safer in the long run squish it over the module and over the actual little usb connector that might be the hardest bit to go over okay now use whatever you normally do to heat heat shrink i use a little hot air pin it's just as part of my soldering station it's quiet it's convenient it's probably what i use it more for than anything else i do use it for actually soldering de-soldering opponents and reflowing surface mount components but it's very handy for doing heat shrink i recommend the clear heat shrink simply because there are leds in this and it means you can actually see the leds it actually helps spread the light around as well so you can actually see even from the edge when the leds are lit right technically speaking i should be able to get a usb lead now oh here is a usb lead actually no let's use this let's do the test properly i'm going to have to find a usb lead now one moment please i have the lead i have also got a string of lights to demonstrate that this can be used to power strings of lights if you're so desire so let's plug this into here this is one of these generic leads you get with random products from china hopefully it's the right polarity let's plug the reading in and we'll see what current it charges at so i'm plugging this in here the little red led is lit and the battery that i was previously hammering over three amps into is now getting 914 milliamps which is a lot better it's still not ideal ideally you would change the resistor in this to 2.2 k to actually adjust it to the um 500 milliamps for the cell but you know what it's maybe worth having a couple of these and writing the current ratings on them so you can charge different cells and plug them on as desired but once you've finished charging it you can then get this stuff out the way use your little adapters to plug into this connector and have led lights asunder and the nice thing is that over time when the battery finally goes down then it will cut off when it reaches the lower voltage it's worth mentioning i put two 10 ohm resistors and series these lights just to control the current through them but if you want uh you can if you you're doing something like this you can well this is actually a little inline adapter you wouldn't necessarily want to just plug it straight in because that would run the leds at far too much current but you can choose the value of resistor you want if you're running leds or whatever you're running little standby work lights or anything you can run off little packs like this they're extremely useful now just before i finish this video i shall bring in those pictures and show you specifically the resistor to change if you wish to actually adjust that to the sort of 500 outlet milliamp level not 500 that would be quite exciting so let's focus down onto that uh in the case of this type of circuit board it's this resistor here it's pin two of the tp-4056 so it's this resistor here you can either put in a new surface mount resistor or just tack on a standard quarter watt resistor it might be easier just shape the leads so that they both come in like that um and then fold it carefully over making sure it doesn't short onto anything with the case of this one pin two it's this little 1.2 key resistor that can get swapped out for a 2.2 k resistor and that is how you're charging your cells properly without blowing up your house so go out into the streets and harvest lithium celsius stuff knowing that now you have the full protection to use them properly good result very handy little devices

Channel: bigclivedotcom

Views: 1,333,139

Keywords: usb, lithium, charge, module, tp4056, safe, recharge, cells, batteries

Id: M88e1r8nvYk

Length: 21min 26sec (1286 seconds)

Published: Sun Jun 26 2022