Question : Does anyone know if they still make a battery charging switch for a car with a sound system?
Hello, About 9 years ago when I was into auto audio systems there used to be a device that you could put in your car that would act like a switch between your main battery (the one that starts and runs your car) and an auxiliary battery (something like a deep cycle battery that your sound system could pull from when demanding high amounts of power). It would monitor the two batteries and it would charge the main battery first and when the main is fully charged it would switch over and allow the alternator of the car charge the auxiliary battery. I was wondering if anyone knows if this is still around and if so what’s it called and who makes it? Or if it’s possible to build something like this that would be I’d also be interested in. Thanks for your time and help! :)
auto sound systems

Best answer:

Answer by Steve M
Is it possible you are looking for a battery isolator? This site might help

http://www.bcae1.com/battiso.htm