Small low voltage "switch off" component?

Hi! I’m looking for a simple DIY solution. I have a number of 4S (14.4v) lithium battery packs (home made) and I’d like to find some kind of simple voltage regulator which keeps the battery circuit closed while voltage is above a fixed minimum (say 12v) and opens the circuit when the pack voltage drops below the minimum. At the moment I have an inline device I bought from Jaycar which is designed to be plugged into car cigarette lighter socket to a load (like a fridge or something) and it cuts out when voltage drops below 11.8v. This is Ok but I wonder if there is a small component that I can install (solder) into the circuit inside the battery case itself which does the same thing?

HI Alistair,

Welcome to the forum!!

There are a couple of gotchas that you might have come across when combining batteries, to keep the LiPo bank safe it’s best to monitor the individual cell voltage rather than an overall voltage (e.g. one cell might discharge faster putting the voltage lower than what’s safe, and the other 3 cells are able to prop the voltage above 12V, giving the impression that its still in the safe zone).

Unfortunately there isnt an easy discrete component you can use, but DIY Perks has a great example of a dicruit you could use to prevent the individual cells from discharging too much: How to Make a Battery Protection Circuit (over-discharge protection) - YouTube

I’m keen to see how you go!