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2032 lithium cell charger with reverse polarity test
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- Опубликовано: 18 янв 2024
- These USB powered chargers are only suitable for charging the LIR2032 rechargeable versions of the lithium button cells. Do not put a non rechargeable cell into them.
Note that the rechargeable cells are not suitable for all devices intended for a CR2032 non-rechargeable cell. Instead of providing a fairly consistent 3V for the full discharge the rechargeable cells start at 4.2V and reduce progressively to 3V during the discharge.
The charge current is about 15mA, which is well within the sensible range for these cells. The strange bypass resistor is odd, so I'd suggest not leaving cells in the charger continuously, although the leakage is small at around 6uA.
The chip seems to have various protective functions for the inevitable time that a cell gets put in backwards.
There is no facility for indicating to "intelligent" USB chargers that the device needs power. If it doesn't light with a fancy charger try a different one.
The little flashing supercomputer badges came from Mouse's Etsy shop. He hand makes them:-
www.etsy.com/s...
The charger came from Temu:-
www.temu.com/g...
The cells came from eBay a while ago.
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:- www.bigclive.c...
This also keeps the channel independent of RUclips's algorithm quirks, allowing it to be a bit more dangerous and naughty.
#ElectronicsCreators
I know from experience that TP4056 does not contain reverse polarity protection. Unless you call "blowing up" a form of protection...
Yeah..... found this out that way too. haha
Blown fuse is absolutly protection. So is a blown resistor.
@@matsv201how about a blown IC?
@@oilybrakesDepends on ones definition of "protection" philosophically thinking... for example they could define "protection" as it not burning ones house down 😅
@@oilybrakes well i guess technically if it protect a more expensive system.
In the Telecom servers i use to work with we had both fuses and resistors specially designed to blow if they got overloaded.
Never knew of a rechargeable button cell, every days a school day.
Thanks for sharing.
Interestingly, the Dreamcast back in the day used a rechargable 2032 for its CMOS... although if memory serves those had the code ML2032, rather than LIR2032.
How utterly fabulous! How many times have I wanted to use vernier calipers or similar & found the battery flat & had to then rummage through cards of mostly unused batteries for a new one. Having something that I can recharge with a few spares is such a pleasant & better way. Thank you for sharing!
Be careful, your vernier calipers may not appreciate the 4.2v from a freshly charged LI3032. Also note the capacity of the rechargeable 2032s is about 1/5th that of the non-rechargeable ones.
@@ferrumignis Ya, reminds me of a thermometer we had once, back when digital thermometers that were cheap enough for home use were kinda new. Replaced the battery with same model number, but of a different brand. I can't remember now if it read way too high or too low, but thermometer was useless till we bought another battery of the original brand. Sensitive micro electronics can be kinda sensitive... Who knew?
One more reason why I still keep measuring tools with mechanical dials around in the shop.
I added a physical power switch to my cheapo Chinese digital calipers, and haven't changed the battery in years. It's just a latching switch mounted in the hole for the data port, with two pieces of copper foil separated by a strip of paper that sit between the battery and the pcb contact.
@@ferrumignisIf you have access to a 3D printer you could print out a protection for your caliper, zeroing the caliper with it.
The battery shell, sides and top are positive, the bottom insert is negative. So if the positive charging contact is at the side or edge and the negative contact is in the middle, this would eliminate the upside down problem.
The wrong insert would only give positive on both contacts.
The contacts are both central.
That was my first thought, so was puzzled when he say put it in the wrong way to see what happen
The weird 150k resistor between VBUS and VBAT I've seen once before on another charger with a removable cell, it's to ensure the charge finished LED stays on with no battery installed, without it the charger IC will constantly charge up the output capacitance which will leak down triggering it to charge it back up again causing to LEDs to flicker which may cause the user to think the unit is faulty.
Also you can actually buy USB C receptacles with through hole pins for power only that have the resistors built in to simplify designs like this. Did you test if it worked on an upstream device that requires the CC pin communication? I've always been interested in where they put the resistors in them.
But I really like the form factor of that charger, although would have expected a male USB C plug so you could use it without a cable. I will note I find LIR coin cells rarely get much attention as very few devices can take them let alone are designed to use them. I suspect because their volumetric capacity is often rather low and price is rather high compared to like a dirt cheap 100 mAh pouch cell. One advantage for me with LIR cells in the past is most can be short circuited and not catch fire unlike many pouch cells which helps meet certain product safety requirements.
I have a very similar one with a USB A plug that can be used without a cable.
I'd happily skip the CC resistors for something like this, I don't really need 3A. The plain USB-C sockets don't have the resistors, the ones with the little circuit board sometimes do, as do the wired panel mount ones. Now I'm wondering what the default USB current is, 0.5A?
LR2032 do have crap capacity, 40mAh vs 200+ for CR2032, and higher voltage too. They are a lithium cell after all, so 4.2v (3,6 nominal), might upset a few things.
Would also say the resistor is there to pull up the battery to fool the charge IC, as it likely is meant to be connected always to the cell, so putting in the cell while powered will mean it will simply stay locked into protection, as it detected a very low battery voltage on power up. The resistor means it will see a high enough voltage, flip the charge transistor on, and immediately charge to full voltage, and say the cell is full, and stay that way. Connect battery and it thinks cell is now discharged and starts to charge it.
@@j.f.christ8421 without resistors (most?) USB-C sources will not provide anything at all, not even 5v 500mA.
Agree.
It may be doing double duty and also being used to trickle charge deeply discharged batteries which is done usually with sub 100uA currents.
One problem with these rechargeable button cells is that they’re around 4V to 4.2V fully charged, while a nonrechargeable CR2032 is around 3V (typically 2.9V under any kind of load). They’re also capable of delivering quite a lot more current (100mA or more in short circuit). This means that they’re not a drop in replacement in all electronic devices - especially those that don’t incorporate any sort of voltage regulation or that rely on the low current discharge limit of a non-rechargeable cell. I have a kitchen scale that uses 3x 2450 cells I think and the rechargeable versions are unusable as the display just turns on solid white due to the higher voltage I suppose.
As others have stated, there is another variant, the ML2032 that has a nominal voltage of 3V and is rechargeable. The disadvantage is that these only have a capacity of around 65mAh compared to the 200-250mAh of CR2032.
ML2032 have the opposite problem: voltage is around 2.5V under load, which is very marginal for some "3V" devices. They have lower discharge as well, the one I tested could do only about 2mA continuous draw, and that at around 2.3V or so if I remember.
@@SamStinson That's good to know. I haven't actually used any as a drop in replacement, but was planning to when the CR2032 of my digital calipers dies. Atleast there is no harm in trying. Worst case I lose a bit of money if they have too low a voltage under load.
So, in my very expensive illuminated reticule riflescope, do you think there would be a noticable brightness difference between this and a disposable cell?
depends on if the illuminated reticle uses some sort of voltage regulation or not@@cascadianrangers728
Interestingly an IC with this marking is listed on a Prime shopping site as Tp4057 SOT-23-6 Lithium Battery Charging IC 500mA Battery Reverse Connection Protection 1% (so it does apparently have reverse polarity protection)
Perhaps that 150k resistor is acting as a pull-up resistor? And the chip checks the voltage on that pin first, before starting the charge, which is why the red light takes a while to turn green? So if it is reversed, the battery pulls that pin far too low, the chip notices something is very wrong, and bails on charging.
Yep, that's my guess too. The chip pin goes tri-state and if it sees 5v it knows there's no battery, a negative voltage means a backwards battery, and some low positive voltage means a discharged battery was inserted.
It could be that.
This was my thought too. I guess I'll have to get up earlier (literally) to beat you guys.😊
Could the 150K resistor be there to lower the voltage? That battery isn’t a 5V battery, so you’d want to lower the output.
A way to test (and possibly destroy the unit) is simply to remove the resistor and see what happens.
Thanks you for coloring the polarity of components on your awesome prints, it's much easier to understand
Just as a cautionary note, don't use metel calipers when measuring the thickness of the cell !!😏
That's why I used plastic ones.
@@bigclivedotcom you probably know this, but you measured 3.1mm because your calipers were zeroed at -0.0, not (+)0.0. these cheapo calipers have two zeros! It's because of the 2's complement binary used in the control IC.
Well, maybe if he does measure it a bit longer with metal calipers the cell gets the designated thickness 🤣
@@ollysworkshop2’s complement only has one representation of zero. 1’s complement has a negative zero, but it’s unlikely that would be used.
@@Mark-px3rq You're right, I remembered that wrong. Ages ago (probably at least 15 years) I made a digital caliper DRO system using a PIC microcontroller. I did the code in assembly and I believe I used 2s complement for the mathematical operations. Looking it up again, the Chinese calipers spit out 24bits where 3 nibbles are the numbers and the fourth nibble is flags, such as negative and metric/imperial. So I suppose it's more of a signed binary. Either way, it has two representations of zero.
Had no idea they had rechargable button cells. We have a security system that has tiny sensors with button cells. Only have change 2 in 2 years but would be good to have rechargeables. Will be looking into these! Thanks Clive!
I have one on my computer motherboard.
As others have said, you can't use the LIR2032 to replace a CR2032 for most devices. Their voltages are different. It might work but could damage the device / cause weird behaviour / ... I believe ML2032 is a suitable (rechargeable) alternative but capacity is much less compared to CR2032s.
@@olafdesneeuwman8983 Roughly, over 3.5 times less capacity than CR2032.
Don't bother the capacity is appalling, I've used these myself
I was thrilled for these rechargeable 2032s until I found out about their capacity ☹
There are also rechargeable ML2032 batteries, which are the same size but 3.0V instead (and generally more tolerant of being overcharged).
your timing is impeccable, to the hour. I was just on the lookout for a 2032 charger.
Thank you for sharing, the timing was perfect. Didn't even realize there was rechargeable CR2032 cells. I was just changing one of these batteries this morning, and was surprised to discover a cell measuring 3.03V was not enough to power a kitchen scale, but yet another one that measured 2.97V did work. 🤔
The cells tend to show around 3V even when their ability to deliver current has diminished. Under load the voltage drops.
That would explain why some of the batteries do not work in my remote doorbell.
Thank you for the explanation of the numbering system for the batteries, never really put that together before for some reason
Ah superb. I was gonna use the 18650 USB charger but these are a ready made unit. Excellent. Cheers Clive.
it's good to note that the LIR2032 is 3.6-3.7v and the MIL2032 is 3v so depending on what you're using it for you might want to go for the MIL2032 instead if your device is expecting 3v.
Hi Clive, interesting video as always.
I thought of a possible mechanical way to provide polarity protection at least for this gizmo. If you designed the battery holder so that the positive contact was a springy metal half ring like you see in some battery holders, just deep enough to contact the side of the positive part of the battery, then if the cell was inserted the wrong way, the negative terminal on the battery wouldn't make any contact.
Cheers from New Brunswick, Canada
I bought a set of plastic digital calipers on a lark. But then I realized it’s the best tool for measuring magnets and batteries.
And plastic/ceramic tweezers for handling small button cells.
Hi,Clive until Isaw this video ,I had no awareness of rechargeable 2032 cells but now that I do I will be able to repair some late 1960s Sony IC radios.Informative as always thanks Clive.
Keep in mind that the traditional cells are a flat 3V while these start at 4.2V.
@@bigclivedotcom How well would these work as CMOS memory batteries in a PC???🤔
@@fookingsog look-up datasheets of bios chips... Gone through few. Supply voltages from 2.4/2.7V to 3.6V. Doubt those will tolerate 3.7-4.2V.
@@bigclivedotcom There is another variant, the ML2032, which has a nominal voltage of 3V and is rechargeable. 65mAh compared to 200-250mAh of CR2032 though. Also takes quite a while to charge at 2mA or lower (numbers straight out of their catalog).
I would expect it to not charge a reversed cell, because a negative voltage is way lower than the threshold for charging. That is, most lithium chargers have a threshold, because if the voltage is too low, the cell is likely damaged, and it's dangerous to charge. If that;s the case here, it would automatically serve as reversed polarity protection I think.
Still good practice to never put a cell in the wrong way round. You can never be sure XD
With classic TP4056 charge boards, reverse connecting a cell will destroy them.
@@bigclivedotcomgood to know, thanks! Didn't consider the consequences for the charger itself for some reason.
I want to see what happens with a non-rechargeable cell!
Fire??
That would make the angry pixies even more angry.
A quick test shows that the voltage shoots straight up to 4.18V and very little current flows. Not sure what would happen with a long term test though.
One moment please - thats somehow so iconic
I bet there's many many eccentric types like myself out there, that tell their significant other, "one moment please" in the appropriate best rendition of Clives accent.....
My guess would be that the 150k resistor is there to prevent the output pin from the charger chip to go negative if they temporarily switch it to be an input when they detect that the cell has been removed and a new cell is inserted. Without the 150k resistor tied to the 5V rail that output, now a input, be at negative battery voltage and that might fry something! 🙂
Amazing 2032 lithium cell battery 🔋
Watching this channel is like flying the Enterprise.
You boldly go where no one has gone before 🎉😊
Maybe the input going straight to the resistor is to have it pull enough current to trigger the treshold of the power supply? Some power banks turn off when there's not enough current flowing.
The current is just microamps.
That was my first thought, too. But then realized that it's way too little current. Someone above said it's likely there to keep the green charged LED on once it's done charging. 🤔
"I wonder if it has protection. There is one way to find out. 50 KV transformer! Mwuahahahaha!"
In the words of Photonicinduction, "we popped it"!
That is one way to find out if it has a full bridge rectifier.
Recently bought an identical looking charger. The board inside is a little different - the passive components are in different positions and it has a little more verbose silkscreening - the components are marked (C1, R1 and so on). It also has a proper USB C connector with all pins, and it works with my Google Pixel USB C charger (which is very particular about standard compliance), so it looks like they use the proper CC pins resistors.
Fantastic! Thanks for looking at this little thing. I was really curious about it.
I suspect the 150kΩ resistor is acting as a pull up on the output. The chip is probably looking for something like +1V to +4V on the output before initiating charging. +5V would indicate no cell present, and < 0V would indicate reverse polarity.
I love all of your videos from the bottom of my heart ❤️
That Image of Clive's hand against the supersized USB connector was twisting my melon man.... 😂😂
Huh
Ayeyooo what ?
I nearly soiled myself when I saw the title. I thought you were going to tell me I could have recharged all those dead 2032s I’ve thrown in the trash over the past decade.
2032 is everybody's favourite button cell
I think the chip acts as a current source and sink. The 150K resistor allows a very low trickle charge on nearly dead batteries with the chip acting as a shunt for anything over 4-ish volts. Check the output voltage without a battery installed.
Quite a handy dandy little device. I didn’t know they existed.
So now I have to go to eBay and see if I can find this
I found them $2.59 for a set of two Thank you Big Clive for hearting this
CR2032s, good for red dot scopes!
Damn, these crooked USB connectors are always cringe-worthy.
And that's not said from an OCD standpoint.
I'll say the circuit checks for the correct polarity for electricity to flow and follow.
*-*- when you put the battery backward and cause the polarity to become **- - the circuit stops the electricity flow which also explains why the LED switches Off if you put the battery backward since that breaks the circuit and stops the current flow through the battery.
The 5769SMD likely has single-direction polarity protecting the cell from getting short-circuited and stopping the electricity from feeding in reverse through the battery damaging it.
150k is likely to hold output at input level so that it detects battery without having output switch on its simply looking for output to drop with in range not too low switch stays off output 5 v switch stays off if output drops a volt or 2 when battery inserted and this triggers charging also would bring a very low voltage cell up slowly to the start charge voltage
nice, the resistor will probably help if the battery gets too low. probably a more common problem with button cells than with larger batteries.
I was waiting for you to use metal calipers to measure the thickness, but I was FOILED.
I got a set of that style of 2032 holder a few years back for, erm, something, I forget what it was now, but I do recall questioning myself as to which way round the cell should be, not always quick off the mark me... :P
I got excited that I would be able to buy some of these for old PCs that stay turned off and unplugged for long periods in my lair. Unforunately, the voltage difference between CR and LIR versions don't inspire confidence. I'll be sticking with the known good CR batteries.
If you're just wanting to keep the clock and boot settings OK for longer and not that fussed about what it looks like, use 2x (non-rechargable) AA cells in series to get 3v and wire it to the battery socket. A good brand of AA cell should run the clock for years. Very old PCs actually had a set up like that as standard before coin cells became common.
I really like your videos!!! I only miss all the ”build” videos, i did make a couple of them my self. (Sorry about my english) hope you never stop doing videos and vill make new live streaming and manu manh more build it yourself videos.
IVe been using LIR 2032 cells for a few years in wearable LED things They are ideal for color cycling LEDs because of the voltage/current needs are pretty similar to the voltage range of lithium cells. They are 4.2v when fully charged, and you cant use them in place of cr2032 cells (3v) unless the device can handle the higher 4.2 volts. They can run a single color cycling LED all night, and a small strand of them for a couple hours.
Thanks, very interesting I would rather re-charge even button batteries rather than throw them away.
The positive side of the cell has a big + symbol in the centre as a clue
sounds like ya getting sicky there Clive 😔, hope ya feel better buddy. good vid though 😃
i dont know why PC motherboards dont use rechargeable ones ,but i suppose all they so is keep volatile date data and will last a decade and most people will update them by that time , i see its benefits for retro console players though where save data is SRAM which is volatile memory using a cell button
There where motherboard manufacturers that did use nicad/nimh batteries for the cmos battery but they tended to leak after a few years.
Just a button cell is easier for them to implement on a board, they don’t have to worry about a charging circuit. Even if it would just be a diode and a resistor
Awesome Video Big Clive 😊
‘This may be tricky to open.” >click< slides right out….
I'm going to have a look to see if there's the same for the battery in my calipers, it would save a lot of money.
I see that the battery contacts are on the faces of the battery, normally on a device that takes a button cell, the positive connection is on the outer edge, so that you get no connection if put in the wrong way. It being a charger I guess it would go have gone with a big bang if they had used that type. 🙂
The amount of these I go through by keeping my keys in my back pocket, I always wondered if they could be recharged. Will keep an eye out for the LIR versions.
They are not compatible with the 2032, just the dimensions are the same.
I buy them off ebay for my keyfob but you still have to recharge them often
@@Breakfast_of_Champions oh right, cheers for the heads up. That could have been expensive aha
@@ifell3 you could use the ML2032, which is also rechargeable and is 3V nominal. Both rechargeable types are way lower in capacity compared to a CR2032 though.
@@ifell3+20% voltage would sooner or later burn out the 3V chip in the fob.
I wish these came with lifepo4 chemistry with a nominal voltage of 3.2V, I'd be a bit worried to put a 4V cell in a device that is designed for 3V.
I've been trying to find smaller lifepo4 cells, smallest so far is AA size. They're perfect for many small projects especially solar powered devices.
am I right in understanding that these can be actively dangerous in CR2032 devices due to the higher voltage? I've something that requires 2 at 6V so I assume I have to use CR2032 or the much more expensive ML2032 options instead
Some devices may be damaged by the higher voltage.
Yes, many electronics with absolute max. voltage of 3.6V are run directly off CR2032 and would die from LIR2032 so be careful. For the 6V device it would depend on the circuit, check if there's a regulator in there.
I didn't know about ML2032 those are neat, apparently they use lithium manganese dioxide chemistry, and the max charge current is 2mA so this charger would blow them up.
If only there were LiFePO4 in 2032 size, the 3.6V maximum nicely coincides with the maximum recommended voltage for 3.3V chips.
and yet I secretly hoped that you would install a non-rechargeable battery. of course with fire dish
That resistor might be to make sure there is constant power draw so things like powerbanks don't turn off
BR2032 actually holds more mA, so needs less frequent charging. Oddly, I just bought four and a different charger on Amazon.
About 5 years ago, a prototype of a charger for these types of batteries were floating around in a kickstarter event. The person who had some claimed they could charge the lithium cells, but alas, it never could (lol).
I was not aware a 2032 cell was also available in a rechargeable type. Just never gave it much thought, I leaned something rather important here, I’d hate to slip a lithium CR2032 into a device that has an automatic charging circuit. 💥
All my bike sensors [heart rate monitor, speed and cadence, actually a pressure gauge too] take these so I thought I'd be responsible and get some LIR2032s they don't don't last very long at all! I have to recharge them every 2 weeks or so, the plastic housing on the various meters isn't designed to be opened that often so now I'll probably just get some really good quality CR2032 that last for a year. Lesson learned eh 😐
Wow, always wondered the difference. 👍
suddenly looking at the circuit board... "look at his small hands"
85c resistor is 75k - nice informative markings with that one. Imagine if it had corroded and you had to replace it.
Hi Clive, that 57b9 chip I think goes under a different number, TP4057. The pin out I found on Digikey
Those LIR2032 batteries are very expensive. I was hoping there would be a rechargeable coin battery because I loathe throwing the damn things out. Local supermarket chain and now accepting batteries for recycling which is good and say they accept the 18650 but specifically state they don't take laptop batteries. Bit confusing that.
*Thank You* for the video Clive, greatly appreciated. 👍
They probably only want loose cells. Easier to process.
They also may not want the pouch style cells that have become increasingly common in laptops people have paid enough to want to replace the battery in.
At first I was thinking the "strange" resistor is for the backwards connectivity. However, once the cell is flipped over, there is nothing contacting the Negative face. So therefore the cell itself is providing the reverse protection.
But, the interesting thing is that the Positive side now is bridging the all 3 pads on the charger. So at this point, the "strange" resistor is now providing the bypass short current protection, I would assume. The resistor would probably heat up over time if you left it connected backwards too long
Probably answered elsewhere, but this is mostly for engagement purposes 😜
Update after reading some more comments. I didn't realize that the Positive was a center tap as well. They are normally wings that clip around the cell. So that kind of tosses out my theory of the contacts not making contact during reverse polarity. However, might still be confirmed with the strange resistor.
Why havnt i been getting my big clive notifications damnit. I got the bell on all too. Anywho hope youre well Clive.
In theory if the cell is put in backwards, all it would do is short the charger out as the negative and positive of the adaptor clip would be shorted due to the design of a button cell with positve on the side and negative on the bottom.
If the contacts are central, top and bottm rather than side and bottom, then maybe the chip has some sort of basic protection. I probably wouldn't want to leave a cell in for extended time to test that theory though.
Good morning Clive ☯️🙏
Good thing Clive used insulated calipers. My only calipers are steel. Battery no likely !
BigC Performs Open Heart Surgery once again! ANd Yet I thought BigC lost all of his patients, since most of his patients, never come out walking out of surgery again! it looks like this patient, has survived!
Most things get rebuilt.
@@bigclivedotcom yes but then that means they are A franken stein! thus, you still lost the patient!
Thanks Clive.
Batteries Not Incuded.
Maybe it needs the trickle current for drained cells to get the carver chip see a minimum load.
Excellent presentation. I didn't know there were Li batteries this small.
I never even knew there were rechargeable coin cells. I never see them in any stores.
If you are ever bored and want a really interesting product to explore... I'd suggest tracking down a "volty switch" multimeter....
Inserting a charged cell the wrong way around will pull the chip output pin hard below ground. I would think that would prevent the output transistor from conducting and probably disabling the chip. A look at the internal circuitry of the chip would be instructive, even just a block diagram.
How fully can a rechargeable 2032 be discharged? That would seem to me to be the critical factor here. At zero volts the chip might try to charge it or it might not.
I was always curious why these batteries have the polarity reversed compared to basically any electric/electronic device. You would expect the capsule's body to be - and the smaller disc +, like with any other battery, or devices with grounded bodies... It still confuses me when I have to deal with them because I instinctively go "- to metal body"...
I didn't know how those numbers worked but I've seen batteries that will fit in a CR2032 holder but they're half the thickness.
Also I had no idea they were rechargeable versions. You think they'd want to set it up so that every time your computer is plugged in it recharges it and if you remove your computer or other electronic device then the battery can be drained in order to keep the clock working and other CMOs stuff idk
2016 cells. 1.6mm thick.
Maybe, the output pin of the chip needs to see a +ve voltage to enable charge output?
If it is dragged down by a reversed battery, or even a shorted battery, the output is inhibited?
it is the extra bits of info i love. for months i have been shoving a cap across the rails on my breadboards. i never knew they were 'decoupling' something. talking of caps, i also never heard of 'class y' caps for 'suppression' till a BC vid. upon research i am intrigued that class y caps are supposed to fail open, not shorted. i'd love to know how they achieve this. i am also chuffed that the 85C resistor in the video is as wonky as some of the ones i've soldered.
I now want to know what happens if you DO put a normal non-rechargeable CR2032 cell in it. Just for science purposes of course.
The voltage shoots straight up to 4.2V but no significant charge is taken.
@@bigclivedotcom So no explosion or fire then? That’s somewhat disappointing, though I probably won’t be testing it anytime soon, just in case.
I have read that under no circumstances should you try to save money by charging this type of batteries, as it may result in a serious explosion (some lithium compounds with explosive properties are created - unlike lithium accu.).
This video is cursed, why do you upload this just two days after I saw an ad of this on Aliexpress.
"Inserted disk" for the negative side is called a nipple.
Maybe it does not have a reverse polarity protection, but the scream of the little chip is so high frequency, we can't hear it :)
The resistor is to keep the charger on. For the smart ones.
The Curious Case of Button Cell Charger.
Did anyone notice Clive's hands are about the size of a usb-c connector?
Few things show quality like a crooked, two-pin USB connector
Perhaps the 150K is there, in the event the battery is very low, the trickle current may boost the battery high enough to start charging,
Something I noticed is the LED indicator turns off with the battery backwards. The chip may have a short circuit protection built into it. I tried running the chip number and the closest I could find was a HM5057B435 at all datasheets. It has a similar charger diagram in the chip's documentation but there's several differences. Some text is in a different language, I ran it through google translate and it does seem to have a built fault protection based on the info. Some the text didn't translate correctly though.
Avoid these chargers! I bought TWO of them a few months ago. I was highly concerned about reverse polarity protection as well and went through the same tests. But after, I tried leaving fully charged LIR2032s in there for an hour or so. One was obviously dead immediately after this reverse polarity test (no LEDs came on, no voltage output) while the other worked... until I did the test again, killing it as well. Two chargers dead and useless in the first day.
The LED is very difficult to see through the a tiny hole you have to view from just the right angle, so a user may not notice the polarity is reversed right away, so destroying the charger this way is VERY likely. What's more, physical reverse polarity protection is trivial on 2032 cells... put one contact in the middle, the other on the edge of the battery holder and you can't reverse the polarity if you want to. One corner too many cut, and not for any great savings... Instead of these, get the dual socket LIR2032 chargers with an LCD display, as those work nicely, give you better insight into the state of charge, and are only slightly more expensive.
For those wondering about LIR2032s in general, they're a good option for higher-drain devices like remote controls. The cells only cost about twice what a disposable CR2032 would, and with the cost of the charger, will pay for themselves after about 3 recharges. However, they're not a very good option for low drain devices that will last several years... there, the self-discharge characteristics of Li-Ion will deplete the cells in a year or two, and may not pay for themselves.
I have pack of 4 double usb output, that I purchased from Amazon. The plugs had the apple design but are very light. Plugged my iPhone into charge and the plug got so hot, possibly meltingly hot. If you would like them to tear down let me know.
I think I will not be using them for their 2.1amp rating
There is no contact on the negative terminal of the battery when you reverse it.