Voltage Drop Through ANL Fuse

[illridge]

Been trying to track down the cause of my voltage drop from alternator to lifepo bank in the rear.....

Tried running another ground to body in the rear.
Tried running 0 ga direct from alt to rear bank.
Tried unhooking from battery (AGM).
Nothing worked.

Finally thought about measuring voltage across the anl fuse holder right next to alt.
Damn thing had about a .4v drop!

I have a 250amp circuit breaker near the rear bank anyway. Fuse prolly redundant. Whatever---I got rid of it. Voltage holding 14 -14.6 at the rear bank! was 13.5 -14 before.

Great. Now my truck sits at 13.5/6 with the car off. And I think it'll stay in the 13's car idling and banging pretty damn hard on the bass.

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[hispls 5,000+ posts]

Fuse prolly redundant.

Fusing on both sides will prevent the wire from burning your car to the ground should it become damaged and short anywhere between those two fuses.

Speaking of, you're lucky you didn't burn up that fuse holder if you were in a condition where it had that much resistance. That's the sort of thing that leads to the pics you see sometimes of those things completely melted.

 

[illridge]

Yeah at 200amps that is 100watts of heat dissapated at the holder.
Strangely, the wires, connectors or plastic showed no signs of melting or high heat.
I'm fairly adept at electrical/ mechanical trades.....
But it wouldn't be the first time I've burned something down or blow something up.

 

[kenvicta]

Been trying to track down the cause of my voltage drop from alternator to lifepo bank in the rear.....

Tried running another ground to body in the rear.
Tried running 0 ga direct from alt to rear bank.
Tried unhooking from battery (AGM).
Nothing worked.

Finally thought about measuring voltage across the anl fuse holder right next to alt.
Damn thing had about a .4v drop!

I have a 250amp circuit breaker near the rear bank anyway. Fuse prolly redundant. Whatever---I got rid of it. Voltage holding 14 -14.6 at the rear bank! was 13.5 -14 before.

Great. Now my truck sits at 13.5/6 with the car off. And I think it'll stay in the 13's car idling and banging pretty damn hard on the bass.

What circuit breaker are you running? I'm looking for a 4/0 compatible or buss bar compatible circuit breaker.

 

[Water Bear]

Yeah at 200amps that is 100watts of heat dissapated at the holder.
Strangely, the wires, connectors or plastic showed no signs of melting or high heat.
I'm fairly adept at electrical/ mechanical trades.....
But it wouldn't be the first time I've burned something down or blow something up.
View attachment 46728

There is a saying in Chinese: many people who drown already knew how swim.

Question though. If you were losing 0.4V across the fuse holder that would seem to imply the fuses in the holder were slightly fried. That could indicate a minor short somewhere (like 1 filament of + wire occasionally touching ground). I'd be concerned about the possibility.

 

[Doxquzme Premium Member]

There is a saying in Chinese: many people who drown already knew how swim.

Question though. If you were losing 0.4V across the fuse holder that would seem to imply the fuses in the holder were slightly fried. That could indicate a minor short somewhere (like 1 filament of + wire occasionally touching ground). I'd be concerned about the possibility.

Agreed, that is not typical at all. - something else is amiss!

 

[Old_Slapper]

One time, I used a fuse that did the same thing. Found the surface of the fuse was dirty. Cleaned it off and it was all good.

In 1998, Rockford Fosgate came out with amp kits. The problem was, the fuse holders would melt. A Fosgate rep told me about this issue and asked why our store didn't have these issues. I told him inline fuse holders came pre-assembled with the wire in them. The other installers assume the wires, in the fuse holders, are tight so they never check them. We found this issue right away and started tightening them. The rep told the company, the shop got free lunch, I got some gear, and Fosgate put out the announcement and started adding L-wrenches to all the kits. You would figure they would have figured this issue out right away. Come to find out, the amp kits were manufactured somewhere else.

 

[audiobaun 5,000+ posts]

cool