Zero LiPo: Batteries in parallel?


#1

Would there be any dangers involved in using many LiPos in parallel?

I want to use a few cells, each with their individual TP4056 charging chip. The output of the TP4056s would be connected in parallel, and fed into the Zero LiPo board. Something like this:


#2

Hi!

That wouldn’t work very well because the voltage drop over the diodes would trigger the Zero Lipo low battery shutdown already when the batteries are about half-full. You’re better off using a parallel battery pack with a single charger, like the 6600mAh one we sell for example: https://shop.pimoroni.com/products/lithium-ion-battery-pack

If you still want to give that a try, remember to use diodes that can cope with the current, as the battery current will be about double the current you’re drawing at 5V from the Zero Lipo.


#3

Right. So if I skip the diodes, it should work (disregarding the potential issues with cells messing with each other).

How about if I connect two 18650:s in series instead (giving ~8.4V), use a buck converter (e.g. a LM2596 board) to get the voltage down to 4.2V and feed that into the Zero LiPo? I’m pretty sure the LM2596 would give a voltage approximately equal to that of the cells when they drop below 4.2V. Would that make the Zero LiPo act properly?


#4

Yep, disregarding cell and charger issues that would work.

Using two cells in series would work too, with a buck converter you could generate 5V straight for the Pi, you wouldn’t need the Zero Lipo at all. This does have some issues too though: The cells need to be well-matched to avoid one cell going empty while the other one still has capacity, and you need some way of cutting the power before the cells go too empty. Also you couldn’t use separate chargers as pictured in your earlier post with series cells, as the cells would short through the chargers.