Fuse or Breaker and Dual Battery Question

[coax]

For the winter months I have slowly been gathering parts to put in my dual battery system. I am going to use the Blue Sea Magnet Latch relay(ACR), as well as a simple fuse block, also from Blue Sea.

The ACR will go either right in front of the original (starting) battery or just behind the newly added house battery.

Ideally, I'd like to put the new fuse block on the firewall by the brake booster which would be wired to the house battery. I'll be powering an ARB fridge and a few other gadgets. This means a run of maybe 7 feet of wire from the house battery on the front-passenger all the way back to the firewall on drivers side. I'd use fairly large gauge wire to both minimize voltage drop to the fridge as well as future proof for the addition of other electronics.

Question is, that seems like a long run of large gauge wire without a fuse, since the fuse block is so far from the battery. Would you all fuse/breaker/electrically protect that wire between house battery and fuse block, or just mechanically protect it and secure it well, and not worry about it? Or am I being too paranoid since the + cables from each battery to the ACR won't be protected either?

I had considered going with the blue sea breaker below which is 100a and costs about 50 bucks. Or is this necessary? Or am I missing something obvious like putting the fuse block right next to the battery and then doing multiple runs of wire through the firewall for all the accessories I want?

 

[ironhippy]

There are many ways to do it. You want to fuse (or use a circuit breaker) most of your cables, definitely the one going to your fuse panel.

It's up for debate if you need to use one between your dual batteries (your stock starter cable is not fused).

Here is an example of a well thought out system:

https://forum.ih8mud.com/80-series-tech/239802-how-power-distribution-part-4-bring-da-power.html

There is lots of other examples if you search as well.

 

[greentruck]

I generally assume any extended run of cabling can be compromised at some point. I make sure that it's well protected against physical damage with looming or other protective covering and tied down so things don't flop or vibrate their way into trouble.

That said, I'd still protect a run like you're discussing. It would be less of an issue if you're the only one working on the truck, as you can trust yourself to be careful around such added wiring. At a garage, not so much and something could go badly wrong with very little effort.

I don't think you need a 100 amp breaker. What is the fuseblock you feeding rated at? There are definitely smaller, cheaper options.

 

[jtaylor]

fuse ing

I ran a fuse between batteries and between house battery and fuseblock. I figured more is better, and safer. I used memphis audio blocks with 100 amp fuses, and a blue sea fuse block.

 

[western flyer]

IMO (and like others have noted), you are correct that your planned run of 7 feet or so of cable from the batt to a new fuse box should be protected with a fuse or circuit breaker to protect the cable (fire danger, etc.). Either a fuse or breaker should be installed inline on this cable close to the batt.

I hooked up a Blue Sea fuse box in the rear panel, and installed a auto-reset circuit breaker directly on the OEM plastic batt box with a short cable run from the batt (actually, from a Blue Sea distribution buss bar also mounted on the batt box). Most trailer supply houses carry circuit breakers of various amp ratings. I have used a couple of these breakers on 2 vehicles, but I have no data on how reliable/safe they are.

Here is a crappy pic of my circuit breaker mounted on the OEM batt box. Those are Blue Sea lug protectors and Ancor cables/lugs.

Mine is similar to the one on the bottom of this page:
http://championtrailers.com/BRAKES_ELECTRIC.htm