Power with LiPO battery


Im trying to power my Cerberus with my LiPO battery from RC car. It is 2S battery so the voltage is OK. I used two voltage regulators to get one 3.3V and one 5V line. So everything is working fine.

The only problem is how to prevent to drain the battery too much. I want to cut off the power supply then battery voltage drop below certain voltage.
I already googled, but I couldnt find any easy solution for this (for example a chip to do that). Can someone know any good solution for this?


I also use a LiPo battery (7.2V) to supply my Panda 2 and Mini boards, the solution I use is to monitor the LiPo voltage through a resistor divider into one of the analog inputs of the Panda, when the battery voltage gets too low (after a bit of averaging to allow for noise) then I hibernate the boards so that the current goes down to 5mA or so, it’s not a perfect battery saver but it’s almost free in terms of components and code.

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you could measure the voltage on an analogue pin but LiPO’s tend to hold their voltage steady until they drop off a cliff so it wouldnt give you much warning. I think there was someone that was looking into LiPO metering on the forum but i cant find the reference to it.

Edit: hah SM uk beat me to it :slight_smile:

Most R/C LiPo batteries have under voltage protection circuits built-in. You might research your battery a little more. This may not be necessary.

no they don’t, its usually the speed controller that shuts them down.

Thank you for all quick replies. I was thinking of analog pins on Cerberus. But first of all hibernation still consume some power so it can drain the battery and if something goes wrong, and Cerberus dont go into hibernation mode, it will destroy my battery. Thats why I was thinking of independent chip to cut off the power.

My bad… I had forgotten where this protection was coming from. I thought I had bought a battery that had it built-in but you are right, it’s actually the ESC that is providing it :frowning: Thanks for catching me.

Take a look at this link. It has a circuit for monitoring LiPO condition.