How do I double the capacity for my project?

Projects General Guidance
1

I have two cells "18650" each one is 2800 mAh

I added BMS for each cell.

I want to charge both of them from 5v usb charger.

I want ~3.7v to my project but I want to double the capacity to last longer. so i need two cells in parallel.

My problem is: I couldn't find charging bourd or balancer that output ~3.7v

All of them will output ~7v and I need to lower the voltage in that case again, that way I'm gonna lose capacity "not efficient"

What if I connected two tp4056 bourds, each cell have it's charger bourd but both take voltage from the same charger?
so both bourds gonna be in parallel.

And what will happen if I connect the output of the two bourds together to my project?

Is there any other way to do it?

2

You can wire those cells in parallel and treat them as one 3.7V cell, with double the capacity. Only one charger is needed.

The cells should be in an equivalent state of charge when connected in parallel.

These contain a parallel battery case, charger and a 5V output, as well:

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3

But after a while they will be out of balance? :thinking: maybe?

lets say:
S1 4.0v
S2 4.1v

And tp4056 charging bourd will stop at 4.1v

What will happen in this case? :thinking:

Wait if they are in series they will always have the same voltage😳
I completely missed that

4

Never, if they are wired in parallel.

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5

Thanks soooo much, I completely missed that :+1:t2::+1:t2::+1:t2:

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