The LIR2032 Battery's and Chargers and Datasheets and Amazon Chargers... Help Ahhhh

Thread Starter

Don Warr

Joined Feb 6, 2024
5
I acquired The LIR2032 3.6v Battery... The Battery Data Sheet say's "Standard Charging Method" = Constant Current at 17ma and Constant Voltage at 4.20V.... Now I acquired charger on amazon that plugs into usb and says FOR charging LIR2032.. But printed on the button cell charger is "output = 4.2v @ 100ma" Question is Is the charger ok to charge battery...???
PS: The charger Led went from Red (charging) to Blue (charged) OK,, but is it charging at to high a current..??
Any comments would be appreciated Thanks....
 

crutschow

Joined Mar 14, 2008
34,457
Question is Is the charger ok to charge battery...?
I would say not.
If the battery says to charge at 17mA then, for longest battery life and to be safe, I would not charge it above that current.

You can make a simple charger to do that with the common LM317 regulator.
If interested I can post a circuit for that.
 

MisterBill2

Joined Jan 23, 2018
18,566
Are you able to measure the charging current?? Do you have any way to verify that the actual voltage will be 4.2000 volts??
The 100mA is the capability of the supply while delivering 4.2 volts. So at least in theory, if the supply is actually 4.2 voltsw then the current should be only 17 milliamps. I have powered my 2-way radio that is stated to draw about 700 milliamps at 12.6 volts, from a 12 volt battery able to deliver over 100 amps. The load only draws the current it needs, as long as the voltage is correct.
 

Thread Starter

Don Warr

Joined Feb 6, 2024
5
Yes, [B]Ya’akov[/B],,, this is what I Need... And the video confirmed that I was reading the Battery data Sheet correctly.. ONLY 17ma charge rate, not 100ma.. I don't know much about Temu as I use amazon but I see there's a charger out there, and I'll find it...

Thank All of you for the guidance......
 

Thread Starter

Don Warr

Joined Feb 6, 2024
5
Well BobTPH you don't see anything is because they don't show the other side.. it says output 4.2v at 100ma... way to high a current for the battery of 17ma..
 

MrAl

Joined Jun 17, 2014
11,489
I acquired The LIR2032 3.6v Battery... The Battery Data Sheet say's "Standard Charging Method" = Constant Current at 17ma and Constant Voltage at 4.20V.... Now I acquired charger on amazon that plugs into usb and says FOR charging LIR2032.. But printed on the button cell charger is "output = 4.2v @ 100ma" Question is Is the charger ok to charge battery...???
PS: The charger Led went from Red (charging) to Blue (charged) OK,, but is it charging at to high a current..??
Any comments would be appreciated Thanks....
Hello there,

Common battery chargers have two main specifications. The termination voltage and the maximum charging current.
For these kinds of batteries, they also have two main specifications. The termination voltage and the maximum charging current.
If either of those specs do not match, it could be dangerous to charge using the charger because it would be the wrong charger.
If both of these specs match, it could be the right charger if the battery chemistry is also a match. The battery chemistry comes into play because of other specs that are not always mentioned or listed. But here let's assume the chemistry matches for now. That simply means that the charger is advertised as being able to charge that particular type of chemistry.

The termination voltage has to match because if the charger spec is higher than the battery spec, the battery can be damaged or even start a fire.
It's the same with the max charge current. If the charger current goes higher than what the battery can take, the battery could be damaged an even a fire can occur.

The charging scheme used with these batteries is where the battery is provided with a current that charges the battery, and when the battery gets up to a voltage close to 4.2 volts, the current starts to decrease, until the battery gets up to even closer than 4.2 volts. As the current gets to a low enough level as the voltage gets very close to 4.2 volts, the charger stops charging the battery. Until it gets close to 4.2 volts though, it could be charging at the full rate of the charger, which would be the current limit for the charger.

The spec called "constant current" is really just a current limit. It sounds like the charger you have limits the current to 100ma. Unfortunately, the current limit for the battery sounds like it is only 17ma. That means the charger would be charging the battery at a rate that is more than 5 times the correct rate. That would be very dangerous for a large Li-ion cell for example, unless the battery has a built in BMS which is a battery management system. If it has a BMS then the battery itself will limit the current. If it does not have a BMS system then the current will go too high for the battery.

The way to test for this since you already charged it, would be to charge it one more time while watching the battery voltage with a meter after the cell has been discharged. If the discharged voltage is 3.0 volts for example and after you connect it to the charger the voltage jumps up to a much higher level (still less than 4.2v though) then the charger is probably putting out too much current for the battery, as long as the battery is new and assumed to be in good condition. Knowing the ampere-hour (AH) rating of the battery helps here too. If the AH rating is say 100mAH and the charger is putting out 20ma for example, the charge time should be longer than 5 hours. That's because 100/20=5, a simple calculation. If it charges in one hour, the charger is putting out 100ma maybe even more.

When you charged the battery for the first time you may remember the time it took to charge. If you know the initial voltage of the battery we can tell if the charger is putting out too much current and there is or is not a BMS system built into the battery. I am guessing that these small cells do not have a BMS system but they may have that too.

So, a test or two would be in order, but because of the rating of the charger being more than 5 times that of the battery, it seems like the charger is just not right for the battery. The question then comes up about why they would make a charger for button cells that puts out 100ma because that sounds kind of high for a button cell. The answer seems to be that it is made for a higher capacity cell or multiple cells.
If we look at other chargers, some specify the compatible ampere-hour battery rating. For example, one puts out 250ma and says the compatible cells are 200 to 500mAH batteries.
As a rule of thumb, the maximum charge rate should not exceed the ampere hour rating. For example, if the battery is 40mAH then the max charge current should be 40ma. That's just a rule of thumb though. A long time ago the max was 0.7 times the ampere-hour rating but I guess these cell technologies improved.

There is another charger I saw on amazon that has four slots: two for 40mAH cells and two for 70mAH cells. The question is, what is compatible with the charger you have now. I would think a 100mAH to maybe 300mAH cell or better would be compatible.
It also sounds a little unusual that the cell would be rated for only 17ma max charge current. Where did you find that spec.

I found a reference that said that all of these kinds of cells have a BMS, but then I found an actual battery for sale that does not have a BMS.
I almost forgot to ask if you have a multimeter that can measure current. You might be able to measure the current if you can find a way to connect it to the charger with the meter being included. It might be tricky to connect up this way, but the test would only last a couple seconds if measuring the current. If measuring the voltage, you could watch the rate the voltage rises, and it should rise slowly.
 
Last edited:

MisterBill2

Joined Jan 23, 2018
18,566
What I recommend is checking the voltage of the charger with nothing connected except the volt meter. The 100ma rating should mean that the charger IS CAPABLE of delivering up to 100ma, not that it will deliver 100 ma into whatever is connected.

BUT for some non-regulated supplies,, including a lot of cheap wall-warts, it means that at the listed current the voltage will be as listed, while at a lower current it will be higher. This applies to un-regulated power supplies that use a transformer feeding diodes to a single-stage capacitor filter. At the no-load condition the voltage will be the peak voltage from the transformer, while at the specified load current it will drop to the specified average voltage.
 

MrAl

Joined Jun 17, 2014
11,489
Hello,

I seriously doubt they would cheap out that badly if they went through the trouble of packaging it and circuit board and all that.
If they used a straight rectified DC output to the battery it could cause a big problem, not only with current but with peak voltage too. They must know the specs of a battery like that. The line voltage deviation alone would void the voltage requirement unless maybe they kept the voltage really lower, which is also doubtful because it would have to be at least 10 percent lower, and that brings the max voltage to 3.8 volts which would be very low for a charger like that.
Anything is possible, but not everything is reasonable.
 

MrAl

Joined Jun 17, 2014
11,489
If this thing is powered by USB, then it might only be getting a 5v input, but it depends where that USB source comes from.
 

Thread Starter

Don Warr

Joined Feb 6, 2024
5
Yes [B]MrAl[/B],,, You explain everything vary well,, And yes I have a complete Lab.. Oscilloscopes, Signal generators, variable power supply's etc.. I think, as I don't design with Coin Cells, and with the charger saying for LIR2032 batteries I thought that I must be reading the battery's datasheet wrong... But NOW I'm on the wright track... You just can't trust amazon sellers to put proper data about there products... Thanks to all, I just needed some inspiration on this subject...
 

MrAl

Joined Jun 17, 2014
11,489
Yes [B]MrAl[/B],,, You explain everything vary well,, And yes I have a complete Lab.. Oscilloscopes, Signal generators, variable power supply's etc.. I think, as I don't design with Coin Cells, and with the charger saying for LIR2032 batteries I thought that I must be reading the battery's datasheet wrong... But NOW I'm on the wright track... You just can't trust amazon sellers to put proper data about there products... Thanks to all, I just needed some inspiration on this subject...
Oh sounds like you have an entire lab there. You can do some good tests I bet. You can look up the way these cells charge and see the current and voltage profiles to get a better understanding, then do some tests. You'll be able to determine what works and what is bad to do.
 

MisterBill2

Joined Jan 23, 2018
18,566
The TS should also be able to use an adjustable voltage DC supply with accurate metering to carefully apply a voltage to one of those LIR2032 cells and observe the current as the applied voltage approaches 5 volts. That information could be useful for a lot of folks who lack adequate equipment.
 

BobTPH

Joined Jun 5, 2013
8,995
The TS should also be able to use an adjustable voltage DC supply with accurate metering to carefully apply a voltage to one of those LIR2032 cells and observe the current as the applied voltage approaches 5 volts. That information could be useful for a lot of folks who lack adequate equipment.
Sounds like a recipe to blow it up to me. If you out a stiff 5V on one if those batteries it would not last long.
 

MrAl

Joined Jun 17, 2014
11,489
The TS should also be able to use an adjustable voltage DC supply with accurate metering to carefully apply a voltage to one of those LIR2032 cells and observe the current as the applied voltage approaches 5 volts. That information could be useful for a lot of folks who lack adequate equipment.
Of course you mean with very limited current limit right?
Those 2032 cells he has looks like they don't take more than 17ma as a max.
 

MisterBill2

Joined Jan 23, 2018
18,566
Of course you mean with very limited current limit right?
Those 2032 cells he has looks like they don't take more than 17ma as a max.
I had assumed that " The TS should also be able to use an adjustable voltage DC supply with accurate metering to carefully apply a voltage to one of those LIR2032 cells and observe the current as the applied voltage approaches 5 volts."
I assumed that "observing the current" would include not increasing it beyond a reasonable level. I had assumed that the TS was able to understand what they were doing.
 
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