P1000 100 amp circuit breaker needed on 2nd battery install with stinger and aux fuse box?

[pfink]

Installed a battery isolator and 2nd battery now looking at installing a stinger relay and auxiliary fuse box for my lightbars. I see some guys run a 100 amp circuit breaker off the 2nd battery before going to the aux fuse box, is this necessary? Also can I run the LED light bar relays off of the auxiliary fuse box? I see some videos of guys going direct to the batteries. I also see busbars. I was not planning on installing busbars. A place for negative grounds would be nice though. I currently am grounding 2nd battery off the negative of primary battery.
I was planning on running my grounds to the auxiliary fusebox and not installing busbars.
Any help would be appreciated.
Thanks!

 

[Remington]

Dont need that big of a breaker unless your runnin homey G dog sound system. I have alot of stuff and a 60amp is plenty.
Yes, id run that light bar through your Aux box with a relay.

 

[bumperm]

A large fuse or circuit breaker, from the aux battery to the "stinger relay", thence to the fuse block, is okay, but not always done. Consider that the function of such a fuse is *only* about protecting that short wiring run from the true isolator to the relay to the fuse block. Consider also, that the vehicle starter circuit has a much longer non-fuse protected run from the main battery to the starter solenoid and then to the starter motor (as is done on most road vehicles). What is key, is that these heavy wire runs are done in a manner so that damage to them, that could cause a short and risk of fire, is unlikely. This is one of those "you be the judge" things. Mine is wired direct from the True to the relay and then to the fuse block with no large fuse or circuit breaker (no buss bar). All the wiring going elsewhere in the vehicle is fused, of course, and this fusing is about protecting the wiring.

BTW, most winch installations are also done sans fuse or circuit breaker from battery to contactor to winch. Care should be taken in running and securing this wiring so as to avoid chafing or other damage.

 

[StewB]

pfink, there are seasoned and good comments above, and surely more to come.

As I was making decisions I hunted around this site, watched videos, and picked my own path, as should you. My build is going to be different from yours, and you should investigate what you need. But don't pay to overkill the system because you may just create more points of failure.

The big difference between my choice and others here is that I don't have a high-watt light bar or electric heating system. If I was to put on bigger lights or a higher draw system, I'd likely go with a stinger or other high-load relay (search this site).
In the end:

1. I installed a dual battery with a True Isolator and the two negative battery terminals are direct-linked by the factory rat-tail (extended to reach). As a side note, I had a twice-to-the-shop stalling problem with my new 2021 P1K5 LE. It felt like a fuel/pump problem, but was as simple as a hard to diagnose loose second ground. The point is to make sure you have a solid grounds however you choose to go.
2. I put a posi-tap on the black/white oem ACC fuse wire to trigger a standard 30 amp automotive relay for key on power (KOP) for all of my accessories. In the future, I may install a bypass switch so I can run lights off my second battery without the KOP.
3. The 30 amp KOP automotive relay then electrifies a marine grade 30A circuit breaker (from Amazon). This is something I didn't need to do. The 30 amp circuit breaker protects everything down system, and it's emotionally nice to be able to flip the switch and de-power everything behind the breaker, but I don't need it. It's an additional point of failure.
4. The 30A circuit breaker then positive powers a 6 post fuse box (these are all over Amazon and Ebay, including with more than just six posts). I am a huge fan of this type of system, and it can eliminate the need for positive and negative buses, and in-line fuses. The box has a negative bus-bar along the bottom, which I have hardwired straight to the negative terminal on the second battery (and thus direct to the first). So I personally have no need for a separate negative bus bar.
5. For my accessories (below), I removed all of the in-line fuses. With a fuse box, the in-line fuses become additional points of failure. But you must make sure to run the accessories through the right Amp fuse in the fuse box if you are going to remove the in-line fuses.
6. My added accessories are 80W front pod lights, a 10W rear light, a street legal turn signal kit, and a 7" under-seat fan blowing back across the headers, and the winch relay/solenoid switch.
7. My winch load wiring is heavy gauge (from the Superwinch box) direct to solenoid and 2nd battery because of the heavy loads. I don't think you should put the winch loads through any relay.

From the above, my biggest regret is going with a 6 post fuse box. Doing it again, I would go with 12 no question.
Peace, out and over. 👍

 

[pfink]

Thanks guys I really appreciate the input and taking the time.