Aux battery for audio

1987R30 · 2024-09-30T21:05:12-0400

I have a 1987 R30 w/454 and TH400. It has the camper special option including a tray for an auxiliary battery. It has the upgraded 94 amp alternator option. I am installing 1100 Watts of audio equipment. I was thinking of installing the auxiliary battery and running the amplifiers off that. But where do I connect to the aux battery? I assume the alternator charges the aux battery?

75gmck25 · 2024-10-01T07:58:02-0400

Check the wiring diagram for your truck. My ‘75 Camper Special has a simple (stock) setup with a relay and charge wire for the 2nd battery that runs to the junction near the brake booster.

- when the truck is running and you have ignition-on power, the relay energizes and the battery positive charge wire is connected to the power junction. This allows the battery to charge from the alternator.
- when you turn the truck off, the relay disconnects/isolates the 2nd battery from the power junction. Anything powered from that 2nd battery when the ignition is off cannot run down the primary battery.

1987R30 · 2024-10-01T10:17:15-0400

I checked the wiring diagram for my truck on the gmsquarebody web site. It shows a relay. I'm pretty sure I have the stock setup. I will confirm it tonight. Thanks.

Grit dog · 2024-10-01T12:29:39-0400

Just parallel the 2 batteries nothing else needed. unless you plan on bumpin for long periods of time parked with the engine off, in which case isolate the “house battery” and run the amplifiers load off of it. There’s a current thread on someone doing that on here. But it’s not too complicated. Just pick what kind of isolator combiner you like.

1987R30 · 2024-10-01T12:56:00-0400

Grit dog said:
Just parallel the 2 batteries nothing else needed. unless you plan on bumpin for long periods of time parked with the engine off, in which case isolate the “house battery” and run the amplifiers load off of it. There’s a current thread on someone doing that on here. But it’s not too complicated. Just pick what kind of isolator combiner you like.

I think I have an isolator relay that disconnects the aux battery when the ignition is off. I'm going to confirm that tonight. If that's working, I would only have to buy a new aux battery and be done. Then, I hope there is a terminal block for the aux inside the cab (but OK, if not)

Aux battery for audio

1987R30

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