Battery protection module (turn off when 3V)

stuartornum

New member
Joined
Aug 2, 2017
Messages
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Hi All,

I'm doing a project to run my Raspberry PI Zero W entirely "off-grid", currently I have:

  • 4.5W @ 5V solar panel
  • TP4056 to manage charging
  • Planning on running 20x 18650s (1800mah ->2000mah tested capacity), currently running 1x 18650 for proof-of-concept
  • 3V to 5V DC-DC converter:https://www.ebay.co.uk/itm/253098313416
  • Raspberry Pi Zero W
The Problem
I managed to run the RPi for 11 hours on a single 18650 (~80% charged), which I was very happy with.
The issue was, that18650 cell died, the voltage wentdown to 1V and will no longer take a charge - I'm assuming the 3V/5V DC-DC converter continued to draw current even when the RPi had shutdown due to low voltage (the RPi has low voltage protection built in)

So my question is, I think I need some form of battery protection that will shut off an current when voltage drops below N (ideally 3.1/3.2V) - I've seen IC protection for individual cells, however, I'd like this to work when I have a 20x 18650 batteryand take the voltage of thebattery instead ofindividual cells.

Any thoughts would be greatly appreciated!

Cheers
 
I guess you got all cells in parallel? If so its the same thing...

First off your solar panel is to small if you ask me. 4x that will do alot better job ;)You need to have enough cloudy days and need to be able to charge the battery bank rather fast.
A simple board like this would work
 
Hi,

Yes, all the cells will be in parallel.

The solar panel I'm using was because I got it for free... as you say 4x would be much better.

Thanks for the link, buying a few of these now.
 
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