Toyota FJ Cruiser Forum - View Single Post - It started with the dual battery kit switch install...
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post #31 of (permalink) Old 05-28-2012, 09:03 PM Thread Starter
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Re: It started with the dual battery kit switch install...

bazross previously said: View Post
G'day dougla2,
Thanks for the message. Yes Murphy's law equally applies down under.. lol
Good advice too, how big should it be ? I am guessing huge..ish, would a circuit breaker work as well ? hmmm, I have a couple of 80 amp inline fuses spare and an 80 amp circuit breaker spare, but I think I should use some thing bigger... 200 amps or something ?
Thanks for the guidance.... much appreciated.
To calculate the main fuse value, I just add up the loads and tack on another 10% or so, and consider the gauge and length of the directly connected wires. Be sure not to exceed the wire capacity since the point of having the fuse is to prevent the wire from melting down and starting a fire or, like mentioned earlier, destroying the battery itself. I'm sure someone will find fault with my off the cuff calculations, and I am open to learning a better way. I added up the fuse values of my accessories and came up with around 100A, and since my wire to the rear is an 8ga, chose a 100A fuse. This exceeds the rating for 8ga wire a bit, but I think the fuse would open before the wire could burn thru its insulation and certainly before the battery fails. And when everything is on, the total load is below 100A. Now, when I add the winch, it will be directly connected to the aux battery and have its own fuse. I do carry extra fuses of each type, which is a step up from the old days when I wrapped a blown motorcycle fuse in the foil from a pack of smokes to get home.

08 Sandstorm 4X4 auto
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