How to? Can XH-M603 charge controller be used to charge auxillary battery in car?

Thread Starter


Joined Sep 15, 2018
I am thinking of installing an auxillary battery in my van. The usual split charging systems or the DC-Dc devices are quite expensive. I thought of using the below charge controller module XH-M603, only $5, for this purpose. What do you think?

Here is how I plan to connect it: + & - (or body ground) from the starter battery will give the input to the XH-M603. Output will be connected to the auxillary battery. The board will be set to turn the charge on at 13.6v (means when the alternator is on) and turn off at 12.6v. This way the starter battery will not drop below 12.6v.

Does this sound right?

A second question: how to wire the battery from an unused fuse socket inside the vehicle? Can this be done instead of pulling wires all the way from the starter battery? How?