Questions about charging module

Projects General Guidance
1

hello! so i have this charging module made for lipo battery and it works fine but i need the battery to be stored at a decent charge for an extended period of time (like years in extreme cases) because its sort of a emergency power supply in case main one fails. I have rtead that the ideal voltage i should keep my battery at is about 3.9V but my charging module only stops at 4.2v and triggers at 4.1V so my question is how can i chnage the cutoff voltage?

thanks for any help, here is the module: JUZITAO Lot de 12 modules d'alimentation de type C USB 5 V 2 A avec indicateur LED (non soudé) : Amazon.ca: Électronique

2

Check the board schematic to find the part number of the charger IC and then check the charger IC datasheet to see if it uses resistors to set the cutoff voltage.

3

But that's not a charging module! It's a ~3.7V to 5V boost converter. It can't charge a Li-Po cell, only discharge it.

Did you post the wrong link?

4

With that module you can't.
Buy a charger that has a battery storage mode.

5

it can surely charge it haha i charged my battery with it here is the link again JUZITAO Lot de 12 modules d'alimentation de type C USB 5 V 2 A avec indicateur LED (non soudé) : Amazon.ca: Électronique

6

what module should i use then? i need it to have 5v 2A output thats for sure

7

i couldnt actually find any datasheet for it, i tried searchign on google but it just gives me other links to buy it, i also tried reaching out to the seller but if theer is an option to do so on amazon, i havent found it

8

I'm sorry, I didn't read carefully enough. You are correct.

It's ok to use this module with Li-Po packs because they contain over-discharge protection circuits. But this module may not be suitable to be used with most Li-ion batteries like 18650, unless you add an additional over-discharge protection module.

9

ive got glap lipo batteries so it should be fine but i still dont know how to cap the maximum charge

10

all i know is that the chip has FM5324GA123S52 written on it but couldnt fina nything on google about it

11

There is sometimes a resistor connected to the charge controller chip which sets the max charge voltage. You would need to remove that resistor from the module and replace it with a different value to set a lower maximum voltage.

If the resistor value for 3.9V is lower than the resistor value for 4.2V then it may be possible to connect a second resistor in parallel with the existing resistor to get to the correct value.

12

i think i found it, here is the link Ip5306 Power Bank | PDF

13
14

I think that is a different but similar chip.

I can't see a resistor that sets the max charge voltage for IP5306 or FM5324G, it is 4.2V and cannot be adjusted.

15

is theer another way to make it not charge at max capacity? if it was just for me i would have kept it as is but since batteries cant be fully charged for long it wont work...

16

Sorry, I don't know the part number for a charge controller chip where you can set the max charge (eg. with a resistor).

The very common TP4056 is also fixed at 4.2V.

I expect such a chip exists, but it may take some time to find it.

17

how do devices like smart watches or pretty much any portable device keep their battery long lasting then? since you sometime dont use them for weeks at a time

18

But are those devices left plugged into a charger for weeks without being used?

Perhaps you could use an Arduino to monitor the battery voltage and control the charge controller chip. When the voltage reaches 3.9V it could disable the charger chip.

19

how do i make it disable the charge chip? i have tried using a not gate cutting the battery directly but the resistors lowered the voltage of the battery giving a wrong reading and not being enough to power the module. they also ended up going up in flames but thats a detail :sweat_smile: . i dont think the key pad can disable charge, only output.

20

the transistors not resistors my bad