Battery in Trunk Wiring That Exceeds NHRA Requirements

[75slant6]

Breakers and fuses are to protect the wire and the equipment. The max power of the supply is not relevant. You upsize the breakers in your house when you increase the service? Of course not.

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http://[URL]https://www.wiresizer.com/ws_userguide.html

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Thanks! That makes sense. So basically, the breaker in the charge wire would be similar to the main breaker in a house and all individual fuses and breakers would be like the individual breakers in a house. That helps a lot thinking of it in that sense. Thanks!

 

[Demonx2]

My $.02...

The avatar uses a 95 amp, single wire alternator with the battery in the trunk. 4awg wire run from the alternator to the battery. I have a maxi-fuse up in the engine compartment and another in the trunk by the battery. Overkill and redundant but that's how I wired it.

Voltage read by the gauge is picked up at my power relay under the dash. Power comes to it from the battery in the trunk. The voltage read on the gauge is virtually identical to voltmeter readings of the battery in the trunk, typically in the 13.8 range. It's worked well for about 4-1/2 years now.

 

[Mattax]

Thanks! That makes sense. So basically, the breaker in the charge wire would be similar to the main breaker in a house and all individual fuses and breakers would be like the individual breakers in a house. That helps a lot thinking of it in that sense. Thanks!

Yes. My point was whether circuits are in a panel rated for 160 amp service or 200 amp service doesn't matter as far the sizing of the individual circuits is concerned. The individual breakers are sized to have a breaker no more than 20 amps on a 12 gage circuit and 15 amps on a 14 gage circuit. If there is any leg that's 14 gage the breaker should be reduced to 15 amps. We also can observe that outlets rated 15 amp are routinely used on circuits with a 20 amp breaker. (I suspect if we had the background on the code the decision was to protect the wire but not the outlets. An outlet failing is contained in a metal box and that probably limits the danger of additional damage. )

As to the power feeds, look at what it is you need to protect while keeping a tally on the maximum load they will need carry.
The factory A-body schemes generally only protected the main wires from letting the battery positive shorting. Until '76 the alternator output did not have its own protection. I suspect the reason was that any short would kill the engine as well as the field circuit - either way the alternator was not going to produce any power. The battery on the other hand has lots of stored energy whether the engine is turning or not.

 

[Mattax]

The sequence for fuses should be
1. figure out the wire sizes based on the loads, distance, heat.
2. size the fuze or breaker to protect the wire or equipment you want to protect