Wiring to battery or alternator?

[mattsk8]

First post here. I have a 1986 K20 that I've built from the ground up. I have a hopefully simple question about hooking up my headlights, horns, off-road lights, and some constant 12v power inside the cab for stereo memory, a CB, Dakota Digital gauges, etc.

I'm installing a relay box, it has 6 fused relays in it. This will operate my H4/H1 headlights, my off-road lights, and my air horns. All this is already hooked up, I'm adding the relay box to clean things up under the hood. My question is... Is it better to power the (fused) 8 gauge wire I'll add to feed the relays off the threaded lug on the back of the alternator, or just come straight off the battery?

My thought is that it doesn't matter because the threaded lug on the alternator gets connected to the battery (via the starter) anyway. But figured I'd ask in case there might be something I'm missing. It would be a few feet shorter if I came off the battery with that 8 gauge feed.

 

[Hunter79764]

Others may have opinions, but I'd say run it to the battery. Make sure you have good wiring from the alternator as well, and make sure you are grounded everywhere. Grounds get overlooked, but can make or break a trouble free electrical system.

 

[DoubleDingo]

I vote battery. And agree, can never have too many, too good of a grounding system

 

[mattsk8]

Others may have opinions, but I'd say run it to the battery. Make sure you have good wiring from the alternator as well, and make sure you are grounded everywhere. Grounds get overlooked, but can make or break a trouble free electrical system.

The wiring is kinda the final stage of this. Right now it has the stock wires on the alternator, but I ordered the American Autowire 8 gauge alternator wires to rewire that too. Was also contemplating ditching the junction on the firewall above the distributor and rerouting that too, just to get the 12v feed further away from the distributor. I need to trace that wire to it's source as well.

 

[mattsk8]

I vote battery. And agree, can never have too many, too good of a grounding system

So far for grounds I have battery to engine, engine to frame, frame to core support, then at the back of the engine I have engine to cab. I think this is sufficient for the main grounds but I'm all ears if anyone thinks more are needed (IIRC there's also a ground strap on each fuel tank). I'll be adding grounded buss junctions on the core support for lights, horn, etc... plus another ground buss in the cab to ground things there too.

 

[dsteelejr]

I also agree with battery. If you’re drawing enough current to need an 8 AWG wire it’s best to route it as short as possible. The longer the wire = more resistance.

 

[Hunter79764]

As long as the grounds are good size, the locations seem spot on.