How to make a USB charger from a tablet battery?

I have a tablet battery, L10C1P22 and it's in good condition. I was scouting through Instructables to see if anyone has made a USB charger based on a tablet battery. And I couldn't find one. So may be I haven't found it despite it being there.
Can anyone direct me to a source that instructs or at least provides a brief idea of how I can make this happen.
Or if someone knows how to, please please share it with me. I'd be very grateful.


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Wired_Mist1 year ago

Need some details, Can you post a Pic of the battery?

If it came from a something as thin as a tablet you probably have a "Li-Po" battery.


^This^ Link will give you some reading material !

To build your Power-Bank you will use a 5V usb connection to power the charger, the charger will charge the 3.7V battery. Finally use a "Boost Converter" to up the voltage from 3.7 to your 5 - 5.2V.

If you are using Apple products then refer to Downunder's post about the data lines!

I want to use for non Apple devices. I was looking forward to some circuitry to understand how to use the above components you have suggested.

Thanks so much!



Wait a sec there may be a problem...

there shouldn't be that many wires coming out of it. should be a balance connector but still doesn't look right. I'll try to find you some doc's

Maybe someone else already knows what the pinout is?

may be this can help ?


I'm not sure but I will try and promote this question.

But, Thanks so much so far!


Certainly helped shine some light !

The outermost wires will have to be the output. use a multi meter on the Ohm setting to see in the two red / two black wires are connected. probably just used 2 thin conductors instead of one thicker one. If that's the case then the three remaining wires would be your balance connector.

You can charge it without a Balancer if you charge it slowly, but it's not ideal. you will need a 3-cell balancing charger to keep the charge constant.

that's Super! Your information indeed is going to help. I will definitely seek out your help in the future. Or atleast I shall keep tell you of my success story if there's one.

However, just one clarification, is this battery a 3-cell one or a 2-cell one?

Plus it would be great help if you can direct me to resources that guide me to the circuitry that would connect this battery to any other device for charging?

As always,

Many thanks


Hey NP; I like a Challange !

Best way to say thanks would be to click that blue button under my name :P

It would be a 4-Cell battery though, check the pic below.

Again Just double check with a multi-meter that the two red are tied together and the two black are tied together.

You will need to buy a balancing charger to charge it properly, like this. Check Craig's list for a used one even.

You will need to make an adapter still. Hit a electronic components store and find a "4-pin JST connector" and wire it up just like the pic. Hopefully you can buy one with wires already crimped on!

Only other way would be to charge each cell individually. Get a 3.7V single cell lipo charger ($10-15) and conect...

red to positive, green to ground for cell 1

green to positive, brown to ground for cell 2

brown to positive, yellow to ground for cell 3

yellow to positive, black to ground for cell 4

would take a long time to charge but could save you some $$


there done!

thanks so much for your information.


And thanks for the BA!

If you have any prob's just reply to something I wrote and I'll get a Email about it. Btw try taking some Pic's. could make a good Instructable !

Good luck to you !

Add a 5V regulator or step down converter to the battery....
For the right charging current configuration check the WIKI pages for the USB charging standard as Apple uses a different system than the normal world.
Without the proper voltages on the data lines you will only get 100mA or if lucky on old devices 500mA chargin current.
Setup right with the voltage on the data lines you can charge with up to 2.1A.