Fused Battery cable?

[bnelson]

Yesterday I got to do a little test drive. While driving battery cable shorted out on the starter case. Shut everything down and started melting wires together. Was pretty easy to narrow down the issue with everything still wide open. This could have been a whole different story if it occurred after carpet, body, bed was installed. Could have turned into fire at worst. This concerns me given the length of the battery cables and inaccessibility of everything after final assembly. One thing I did do was relocate the battery to behind passenger seat for just this reason. Imagine if the battery was under the bed that was bolted down.

So for the sake of peace of mind I would like to fuse the main battery cable right at the battery. Anyone have any suggestions on a source for this? What amperage would be low enough to protect but still high enough to keep it from popping with normal draw?

[65 Cobra Dude]

Another option is a main battery cutoff switch. If you go this way, don’t buy a cheap one. I use Cole Hersey marine ones and have never had an issue with them. If you are running fuel injection, you’ll need to run a 10 amp fuse across the terminal as a keep alive for the computer.

Henry

[FF33rod]

I don't know why this doesn't come up more often. Car batteries can source large amperage and as you found out, a short in the right/wrong cable could be disastrous. We fuse all the smaller circuits, not sure why it isn't common to fuse the larger one in a car. You can go one of 2 routes - a fuse or a resetable breaker. Fuses are AMG or ANL style, this is what I used. Go 175 or 200A. I've seen some of the 12V 200A resetable breakers on Amazon. Go with a reputable company like Blue Sea.

Steve

[bnelson]

I don't know why this doesn't come up more often. Car batteries can source large amperage and as you found out, a short in the right/wrong cable could be disastrous. We fuse all the smaller circuits, not sure why it isn't common to fuse the larger one in a car. You can go one of 2 routes - a fuse or a resetable breaker. Fuses are AMG or ANL style, this is what I used. Go 175 or 200A. I've seen some of the 12V 200A resetable breakers on Amazon. Go with a reputable company like Blue Sea.

Steve

Yea. Makes no sense to me. looks like about $20.00 can prevent a costly mishap. Think I'll go with the resetable breaker. That way can operate as cutoff switch as well.
Thanks!
Bruce

[FF33rod]

Just a side note, I have seen some run multiple wires from the battery. If they are both really heavy, probably no issue running them through the same fuse/breaker. However, if one is significantly smaller, should probably protect that separately with a smaller amperage rating (just like we do on the other secondary circuits)

Steve

[Papa]

I've seen this recommended a lot in various build threads:

https://www.amazon.com/Blue-Sea-Systems-100-300A-Block/dp/B000THUQQW/ref=sr_1_6?keywords=mega+fuse&qid=1580667117&sr=8-6

The listing is for the carrier, and you'll need to select the appropriate fuse to go with it.

[acmikee]

why not just add a stating solenoid which will isolate the battery from the starter. easy and cheap fix

[sperger72]

Ben,

What did you do with the Max fuse 250Amp?

Zach

[JimLev]

Another option is a main battery cutoff switch. If you go this way, don’t buy a cheap one. I use Cole Hersey marine ones and have never had an issue with them. If you are running fuel injection, you’ll need to run a 10 amp fuse across the terminal as a keep alive for the computer.

Henry

That will keep the computer memory alive but if you forget to turn the cutoff switch on and try to start the engine you'll blow the 10 amp fuse.

[Old Timer]

I used this holder. It is rated for 500 amps, so should take anything a normal car would throw at it.
I used a 500 amp fuse, as a short will be a couple thousand amps I would think.
I would think a 300 would work as well. I keep a spare fuse with me.

https://smile.amazon.com/gp/product/B001PYSUP2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Fuse

https://smile.amazon.com/MEGA-Fuse-Time-Delay-Bolt/dp/B07TM7PWP2

[65 Cobra Dude]

JimLev,

Absolutely correct! I’ve done it a time or two. As soon as you turn the key, you remember. I put the keep alive fuse close by.

Thx,

Henry