Upgrading to 0Gauage What Fuses?

[dman4486 5,000+ posts]

I feel as if that the fuse before the back battery is almost not needed, due to the fact if the front fuse does pop then power will be cutoff from the back. The only way I see that fuse serving a purpose would be if say the front battery fails and power from the back battery is needed and then the power would be pulled to the front.
Don't know if that makes much sense, but its just my train of thought. Even if that extra fuse MAY be never needed, a fuse is the best insurance you can buy, therefore it will not hurt anything to have an extra one

your logic is flawed.....the second battery is a source also....so if the front fuse pops, the rear battery is still at 12.8v which would go directly to ground

 

[BLACKonBLACK98 10+ year member]

if the positive parallel wire grounded out after the fuse then it would be hot going from the rear battery up.

heres how i would do it:

alt -> bat - 300a

f bat -> r bat - 2x 300a (12" from each battery)

r bat -> amp - max current draw

 

[DBDRAGGUY 10+ year member]

The idea is the wire will carry 300 amps, your amp will draw 120. From your alt to battery 1 needs to be 300 amps, from battery 1 to battery 2 needs to be 300 amps. from the 2nd battery to your amp should be 300 amps. the amp has an on board fuse of 120 amps.The fuse is a safety just like a breaker in your house if you exceed the rating of the fuse the power is disconnected. You need 3 300 amp fuses in all, To protect your vehicles electrical system from a + to - short circuit. If you fuse between battery 1 and battery 2 and not between battery 2 and your amp and the battery 2 short circuits blowing the fuse in your amp but leaving power from battery to to the point of the short it could result in a fire.

 

[Got_Bass89 10+ year member]

You think going to your amp you need a 300a too

 

[grassroots 10+ year member]

The fuses are protecting the wire. Fuse to the capacity of the wire.

Correct.

Fusing a 0 guage line at 120 amps is limiting the wire. 0 guage is designed to carry 300 amperes. If your amp is fused at 120 and that is the total max draw of the entire system you are ok. If you add more power in the future you will need to adjust your fusing accordingly. What I would do in this situation is fuse the 0 gauge at 300, and fuse within a foot of your amp to 120. Even if the amp has on board fusing. Think of the fuses as a safety net. You are protecting your cars electrical, and your equiptment from a short circuit. The point being where your fuses are needed is install dependent.

wrong.

unless your amplifier doesn't have an internal fuse, an inline fuse will do nothing to protect your equipment. it is meant to protect the wire only. THEREFORE, fuse to the rating of the wire installed like wrenchguy said.

and no, you cannot "limit" the potential of the wire by using a lower amperage rated fuse... your amplifiers only draw as much current as they need...

example... i have ONE 150A fuse between my front battery and rear battery with 2/0 and a 250A alternator... i haven't blown that fuse because even at full tilt my amplifiers don't draw over 150A so there is never more than that traveling through my wires and fuse...

 

[Got_Bass89 10+ year member]

BUT when you do it that way like a 150a from bat to bat it can limit it... your back bat is being drained and recharged every time the bass hits. I agree the wire going to amp from the second bat will only draw what the amp needs but not for your bat to bat run. 250-300 should be a must for alt to bat and bat to bat fuses wether your running 1 fuse or 2. which should run 2 to protect both batterys if theres any short in the wire. I Just not sure on whats a safe amperage for my sec bat to amp run... like i said amp has 160a of fuses and 0guage rated for 250. Probably gonna just throw a 200 in there