Fusing confusing for a Bluesea ML-ACR

I am installing a dual battery set up. I had intended to have a 200 A fuse next to each battery.

One of the attractions of the MC-ACR is the ability to combine both batteries.

I was surprised to read in the installation instructions for the relay that if it was intended to combine the two batteries, fuses should be left out.

What are others doing? I would feel much happier having a fuse next to each battery.

Am I too cautious?

 

How long is the run wire? If they are side by side or nearly so, don't worry about it. If there is a long run under the truck or somewhere the wires could get pinched or chafed then you should use a fuse or breaker.

My aux batteries are behind the seat. I mounted the ACR under the hood and run 2 gauge wire under the truck (protected by braided sleeve and nylon split loom). Before the aux batteries, I used a blue sea battery switch and 150 amp breaker. The switch is wired as a breaker bypass for a high load if needed. Normally the switch is off and the current passes through the breaker. Howeve the switch can be turned on and the circuit breaker tripped to allow full current.



However I don't have any circuit protection on the front end of the wiring and it makes me nervous. I'll likely be adding a breaker there and possible just making a short jumper wire to bypass if needed. Undecided.

 

Thanks.

My house battery will be in the bed. More than ten feet of wire.

 

I used well over 10 feet as well. There was no good way to run outside the frame rail due to the fender design, or inside the rails due the proximity of the catalytic converters. I considered running wiring through the firewall and inside the cab but in the back seat, I still would have had to do something odd to get the wiring where I wanted it. So I ran mine around the top of the engine bay to the center, then down, and secured it on top of the transmission and transfer case, attached to the factory harness.

Anyway... It is definitely a good idea to put a breaker on both ends.

In all honesty I've never needed a jump, but jumped several other cars. So I rarely see that I would use this function. I also realized that I'll probably still carry cables to help out others. Consider carrying cables long enough that you could use them to jump your own batteries with them while locking out the ACR. Seems kind of stupid but at least both sides of the wiring would be protected, and if you carry cables anyway....

I know I was intrigued by the capability as well, but probably moreso for the novelty than actually doing it. I would feel stupid if I left my jumper cables behind and I wasn't able to help someone who was stranded anyway.

 

Both ends!

So, one after the replay but before the big run, and another near the house battery out back.