What do you recommend? Trunk Battery, like to put a inline fuse. what size?

davescuda

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What do you recommend?
I am putting my battery in the trunk. I want to put a inline fuse or circuit breaker off the battery in the back. Most likely going to use a circuit breaker. This way I do not have to worry about a fuse.
What amperage should I use?
I did go with a 100 alternator if that matters.
Thanks for the help.
 

kursplat

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when i tried to research this recommendations were all over the place. i ended up with a 250a maxi fuse
 

toolmanmike

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The starter draw is the highest load. You would need a battery load tester with inductive pickup amp capabilities to see what your starter is drawing while cranking. As starters age/wear their amp draw increases so your fuse or breaker will need to be larger to cover the added draw. Your starter may draw a couple hundred amps. Old starters may draw 4 or 500 amps. It all depends.
 

davescuda

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The starter draw is the highest load. You would need a battery load tester with inductive pickup amp capabilities to see what your starter is drawing while cranking. As starters age/wear their amp draw increases so your fuse or breaker will need to be larger to cover the added draw. Your starter may draw a couple hundred amps. Old starters may draw 4 or 500 amps. It all depends.
Thanks, I am using the Mopar mini starter
 

67Dart273

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You can't really fuse the main line. The only thing you would protect is the big fat cable. Fuse/ breaker/ fuse link the main alternator output sized appropriate to the alternator. Fuse / breaker the rest of the loads coming off the main feeding whatever they feed, fans, pumps etc, and keep those fuses as close to the main line as possible, because in this case it's not really possible to fuse the main line.


The other strategy is suggested by guys like Crackedback, which is to use a rear mount Ford type relay / solenoid to "key" the starter, so that the main line is only hot during starting, then using a smaller feed for the other loads. This line could be small enough to protect. It's size is going to depend on vehicle electrical loads and the alternator output. That feed might vary all the way from no6 to no4.

That in part is why this problem can get so complicated.......there are simply lots of variables. Or as crackedback has been known to say, "more than one way to skin that cat."
 

Syleng1

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Dave,

Off route 10 over by you is a truck parts and (over the road truck/trailer) repair shop.
Kinda near the DMV license test place - (the side road across the street)
They sell a circuit breaker that is reset-able for lift gates on big trucks.
Look for 400 amps and use large diameter wire like 1/0 because of the distance you are traveling. It does weigh a bit more BUT you loose alot over the 16ft run. The wire will heat up and cause even more resistance if you go too small in diameter).
Mount the reset-able circuit breaker nearest the battery. Also you can "trip" the circuit breaker as a means of theft prevention.
 

kursplat

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You can't really fuse the main line. The only thing you would protect is the big fat cable.
which is what i settled on. went a little under what the cable was rated for and doesn't blow the fuse starting the car
 

davescuda

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Dave,

Off route 10 over by you is a truck parts and (over the road truck/trailer) repair shop.
Kinda near the DMV license test place - (the side road across the street)
They sell a circuit breaker that is reset-able for lift gates on big trucks.
Look for 400 amps and use large diameter wire like 1/0 because of the distance you are traveling. It does weigh a bit more BUT you loose alot over the 16ft run. The wire will heat up and cause even more resistance if you go too small in diameter).
Mount the reset-able circuit breaker nearest the battery. Also you can "trip" the circuit breaker as a means of theft prevention.
Thanks, That’s where I bought my wire. They actually recommended the circuit breaker, he just did not know the size I should go with.
 

kursplat

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that CB doesn't automatically reset does it? post some pics when you do the install too
 

Syleng1

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that CB doesn't automatically reset does it? post some pics when you do the install too
No they do not. Its a lever (small and red) that has to be manually moved 90 degrees to reset.
That's a lot of amperage to "pop" it. So if there was a major short, you will be glad it did not do it automatically.
On a truck lift gate they pull up to 350 amps with a single starter type drive motor.
 

davescuda

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No they do not. Its a lever (small and red) that has to be manually moved 90 degrees to reset.
That's a lot of amperage to "pop" it. So if there was a major short, you will be glad it did not do it automatically.
On a truck lift gate they pull up to 350 amps with a single starter type drive motor.
I went there today and they said they only have 200 amp circuit breaker that you can reset. Bummer
 

Needswork

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My suggestion is to search the internet for 'MRBF Terminal Fuse Block'. They have various ratings up to 300 Amps. They are compact. It's a fuse instead of a circuit breaker, but it provides the protection you need to prevent a fire. You can always carry a spare fuse.
 

RustyRatRod

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@crackedback's deal is the damned best way to do it, bar none. It might have some stuff in it you may not "need" but it flat out WORKS. I tagged him so maybe he'll chime in.
 

Syleng1

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The other place to go is Clines truck and trailer in Portland CT right on 66- just the other side of Middletown. About 20 mins from you.
 

davescuda

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@crackedback, where you at, dork?
I did find this that he posted.

2C6A8B6D-F26F-4A2B-9EE6-71D4E67B1438.jpeg
 

crackedback

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Are you using a cutoff switch? I don't like having the starter cable hot except when starting the engine.

I would run starter off a ford relay. Run a second 4-6ga cable forward and fuse that line for the amp loads the car is expected to use. Any high amp draw systems that are typically on when engine is running, draw right off the alternator charge stud.

Running a cutoff the above schematic works well. Fuse the line running to the starter relay.
 

RustyRatRod

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Are you using a cutoff switch? I don't like having the starter cable hot except when starting the engine.

I would run starter off a ford relay. Run a second 4-6ga cable forward and fuse that line for the amp loads the car is expected to use. Any high amp draw systems that are typically on when engine is running, draw right off the alternator charge stud.

Running a cutoff the above schematic works well.

Bout time dangit. You'd think you gotta life or sumthin. lol
 

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