battery relocation question

[black91turbo]

alright.....now that i mounted my optima, i need some help with wiring. I read a great link on MKIII tech.com about doing it but had a question that no one there answered. Couldn't I just run an inline fuse (like this one http://cgi.ebay.com/FUSE-HOLDER-INL...4|66:2|65:12|39:1|240:1318|301:1|293:1|294:50) to the wire going to the starter and not worry about running wire to the alternator via circuit breaker or kill switch since i do not really take the car to the track? BTW what amp fuse do i need to run? I was told 30...sound right? thanks for all of your help

 

[SySt]

You obviously do need the alternator connected to the battery some how. I was not sure by your post if you had that figured out. An inline fuse is probably just fine if you are not trying to meet track requirements. 30amps is way low for that job however. I would look at using 150-200 amps, the link you posted claims a 150amp fuse is included.

 

[black91turbo]

my fault man, i guess its written kind of awkward. I was trying to ask whether or not I can get away with using fuses for the power wire going to both the battery and the alternator instead of using the circuit breaker. Im sorry, i am rather ignorant when it comes to this stuff. How do you know to put a 150 amp fuse there if the alternator i have only puts out 80 amps? (just trying to understand) thanks

 

[Johnysupra]

If you happen to be running every single accessory in your car plus all the sensors and ignition system you may well pull near 100amps or more.

On big reason for a fuse if you short to ground, especially with a relocated battery. You want a fuse as reasonably close to your battery as you can get. So if your main power wire shorts to ground instead of catching on fire it melts the fuse.

 

[black91turbo]

oh ok.....i found another post in supraforums........http://i46.photobucket.com/albums/f106/boostaddctn/bat.gif

So based on that pic.....how come i would run 150 amp fuses but only 100 amp breakers? and if i was to use a circuit breaker...what voltage would i need? thanks for your help guys! i am learning more here than i have so far through 3 classes today!

 

[Johnysupra]

Fuse's and breakers don't go by voltage, only current (Amps)

 

[black91turbo]

ok thanks, now how come 100 amp breaker vs the 150 amp fuse from the picture link? also from supra forums.....how about these....it says that they are 12 volt dc rated http://www.solarseller.com/dc_circuit_breaker_breakers_rated_up_to_80_volts.htm What does that mean? what is the benefit of running a circuit breaker as opposed to a fuseable link?

 

[black91turbo]

If I am understanding this correctly.....here is the way this should work:

starter power wire to kill switch, alternator power wire to opposite side of kill switch, power wire from battery to same side of switch as the alternator to prevent the car from staying on and running off of the alternator when switch is turned to off. If corrections need to be made, please let me know. Also if anyone knows the answer to my questions in the previous post, your input is much appreciated! thanks for all of your help

 

[SySt]

Maybe you could get by with an 80 amp fuse. However, like stated above what you are mostly concerned about it a short to ground on the main power cable. If it shorts to ground it'll generate enough heat to pop a 150 amp fuse in no time. So basically you want to give yourself some room to play with so that you won't be popping the fuse under normal operation like if you used an 80 amp fuse (not that it would happen, but it's possible.

A fuse is a type of circuit breaker...The breaker you are referring to won't need to be replaced everytime you go past it's rated current like a fuse would. Thats essentially the main difference.

Also, just to clarify. Circuit breakers are rated for a certain amount of heat. Power throughput being a decent measure of that heat. So a 150 amp fuse when we are talking automotive is rated for that current at 12 volts. Don't go thinking you could use such a breaker on a 110 volt system like in your house and expect it to hold up to 150 amps.

 

[black91turbo]

Maybe you could get by with an 80 amp fuse. However, like stated above what you are mostly concerned about it a short to ground on the main power cable. If it shorts to ground it'll generate enough heat to pop a 150 amp fuse in no time. So basically you want to give yourself some room to play with so that you won't be popping the fuse under normal operation like if you used an 80 amp fuse (not that it would happen, but it's possible.

A fuse is a type of circuit breaker...The breaker you are referring to won't need to be replaced everytime you go past it's rated current like a fuse would. Thats essentially the main difference.

Also, just to clarify. Circuit breakers are rated for a certain amount of heat. Power throughput being a decent measure of that heat. So a 150 amp fuse when we are talking automotive is rated for that current at 12 volts. Don't go thinking you could use such a breaker on a 110 volt system like in your house and expect it to hold up to 150 amps.

thanks a million for your help! so really i can use the inline fuse rated at 150 amp and not worry about the breaker.....only caveat being that i will have to swap out the fuse if it does blow....I guess my next question is how much continuos amp should my kill switch generate is 175 good enough?

 

[SySt]

I would have the switch rated a little over the fuse rating. So yes, 175 amps is a good figure.

 

[black91turbo]

I think i have it figured out! thanks for all of your help guys