Dual battery/accessories wiring questions

[fireball]

Hello all,

While I've got the interior of my truck torn apart cleaning everything and sound deadening, I'm going to add a 2nd battery and do some wiring. I'd like to take care of all the wiring now and add the components as funds allow. There are some good threads with lots of info that I've been reading, but I have a few specific questions I'm hoping to get help with:

1. Do I need the 2nd 200amp breaker/fuse as pictured at the AUX battery? Isn't the one by the main battery enough?

2. the Aux battery needs 2 grounds, correct? Local ground plus common ground back to the main battery

3. What gauge wire back to the aux fuse box? This will be the bluesea safetyhub 100 or 150. Was planning on 4#.

4. Amp wiring - I was going to run this from the aux fuse box, but since it is mounted under the pass seat and my power run will be going right by it, was considering either running a 2nd line direct from aux battery, or just running wire to a fused distribution block right at the amp. Does it matter how this is done?

5. Compressor - lots of folks with cargo boxes seem to be mounting the compressor in the cargo area. I drew it up that way, but then got to thinking that it might be better in the engine bay. Any thoughts on preferred location?

6. Ground block for accessories - I believe it is RobRed's wiring diagram that I have a photo of that shows a ground wire running from aux battery back to fuse block and used as a common ground point for all accessories. Is this needed? Can you explain why so?

That's all for now! Thanks in advance for any help!

 

[SWCruiser]

Fireball,

1. you do need a fuse between the aux. battery. You do not want to use only the factory fuse.
2. Not sure what you mean here. You should ground the battery to the frame in the engine bay. I would also run a line from the batter to the fuse box. Some people just ground the fuse box close to where you place it. After reading about marine/ rv wiring i choose to ground the fuse panel directly to the battery. i don't recall the exact reason but i like to be overkill on electrics..
3.#4 should be sufficient for 100 amps. Im pretty sure its not rated for 150 amps. why do you need a 150amp breaker.. Its unlikely you will need more than that unless you running a bunch of stuff.
4.
5. some people mount the compressor around the wheel wells and not under the hood where its subject to heat. i prefer my compressor out of the elements.
6. see #2

 

[Sandroad]

With regard to #3, what will be the amp draw of the inverter and the compressor and will they ever run at the same time? 12VDC circuits can draw a lot of amps and need big wire to avoid voltage drop. I can't offer a specific number for gauge without knowing the draw, but from my experience the bigger the better with low voltage wiring.

 

[fireball]

"SWCruiser ----- Fireball, 1. you do need a fuse between the aux. battery. You do not want to use only the factory fuse. "

I meant to say do I need two 200 amp fuses, both of them new, both of them close to the positive connection on each of the batteries? I think some people just use one fuse close to the main battery on the new positive wire that connects to the auxiliary battery, I read somewhere that someone suggested a second fuse.


"SWCruiser ----- 2. Not sure what you mean here. You should ground the battery to the frame in the engine bay. I would also run a line from the batter to the fuse box. Some people just ground the fuse box close to where you place it. After reading about marine/ rv wiring i choose to ground the fuse panel directly to the battery. i don't recall the exact reason but i like to be overkill on electrics."

Okay, thanks for the info here. Ancillary battery will then have three ground wires, one back to the main battery, one grounded locally, one wire running back to the auxiliary fuse panel.

Thanks for the help!