Q's on putting in 2 Batteries

[87sunsport454]

That is what I was thinking is that there must be another power wire coming off the radio. It was way to hot to go digging around under there to have a good look.

If I can get the radio to run without the master button pushed then I would not move any of them. To run amps and such do you still use a circuit breaker or just a on/off switch so when you park you just turn a switch off? Are breakers/fuses needed for this stuff?

[rludtke]

The circuit breaker and the fuse accomplish the same task. You can user one or the other. Fuses work one time, but they are cheap. Circuit breakers are re-settable (reusable) but cost a lot. The function of circuit protection is to protect the wire, not the equipment (most modern equipment feature built in protection) from excess amperage (current flow). If something caused a hot short, the wire would quickly overheat and ignite if something wasn't able to remove the flow of electricity through the wire. The fuse or circuit breaker offers this protection. To design an electrical system correctly, it should feature circuit protection of some sort.

In order to size the circuit breaker properly, you need to know what size wire you should use on the circuit. To do this you determine the load that the equipment draws, and you factor in the length of the wire (to account for voltage drop). The result describes the wire size. Then the circuit protection can be determined to protect the wire size/length chosen for the given load.

Try this calculator, as it will select both the wire size and the circuit protection value required for the circuit: beta.circuitwizard.bluesea.com

If you have equipment that you wish to control by one common switch, such as amplifiers and the stereo deck, they could be wired in parallel on a common circuit and switch if the combined loads are not to large. Otherwise, you may wish to use a relay on the switch circuit which in turn energizes the larger circuits that feature their own circuit protection.

Most modern stereo decks feature outputs that will energize the amplifiers so that they turn on when you turn the deck on. This simplifies your life, as you don't have multiple switches, and you won't accidently leave your amps powered unintended. But, this output probably will not be adequate to power large or multiple amplifiers. This circuit could be used to energize a relay, which could then energize a properly designed circuit featuring circuit protection for each amp. This concept would not feature any switches, as your deck already has the on off switch built in, but it would feature seperate circuit protection for the deck, and each amp.

I hope this helps, hit me with any additional questions...

[jzelt]

With the combiner in my system, I have a 1/2/all/off switch that has a common post. The stereo is directly wired to battery, the accessory is wired to the common post. Therefore, it will work off whichever battery is selected. Hope that helps.