Fuse/circuit breaker questions for dual battery system.

[PhilActual]

I'm in the final stages of design and parts accumulation for my dual battery setup. My isolator/solenoid is a cole hersee 200a smart solenoid. I bought a 200a circuit breaker for the aux side and a 200a fuse for the starting battery side.

My questions is if I attempt to link the batteries to "jump start" my truck will it blow the fuse/breaker? Thank you in advance!

 

[PhilActual]

Maybe I should go with a slightly higher amp fuse and keep the breakers the same since I can just reset them. I was also thinking of installing a high amp switch to bypass the solenoid all together. The only reason I'm using a fuse is the limited space under the hood.

 

[dwh]

I doubt it will be an issue. I've self jumped the 460 big block in my truck through an 80a solenoid a few times...no strain at all. No fuses or breakers either since it's all under the hood.

Most fuses and breakers are designed to blow or trip easily in a *major* overload and to not trip or blow easily on minor overloads.

 

[dwh]

Technically, the wires are in "open air", not in a conduit or raceway, and that's a different ampacity table anyway.

So yea, agree with Verkstad, you can probably go higher on the fuse rating.

 

[PhilActual]

Thanks for all the help guys. I rarely need to jump start my truck but I work in remote areas and have to be self reliant. I basically overland for my job as a Timber Cruiser. I put on about 30,000 miles a year.
It's these nit picky details that keep me up at night. I'll post up when it's all finished! Now if I could just get some time off work...

 

[Rando]

I had a similar conundrum with the dual (starting/camper) battery system I am putting together for my new FWC and decided on a different solution - carry one of these for jump starting:

This way I don't have to design for starting/cranking currents on my battery interconnect and can use much lighter wire, smaller breakers and better, lower current, combiner (Blue Sea ACR). It is also nice to have a totally independent backup power source in case something goes really wrong with the main power system and I end up running down both batteries. It is also available to offer assistance to others I may encounter.