What size fuse for 180 amp alternator???

[Philstang]

I just upgraded to a 180amp alternator on my daily S-10. On the dyno sheet the alternator actually maxed out at 196amps.

I have a 4 ga. upgraded wire running from alt to battery which had a 120amp fuse in it. Upon startup the 120amp fuse blew. What is the correct size fuse to use in this situation?

I am running the Taurus e-fan on my s-10 and the high setting uses a lot of juice, heh heh...

Thanks

 

[HISSIN50]

I dont see why a 120 amp [slow burn] fuse would have blown - is there any other issue?

I would fuse the circuit for the weakest component - in your case, it would sound to be the 4 AWG cable (I wont post ideas becuase it depends upon the length of cable used).

For fun, did you check on any S-10 forums? We have one in the family and 200 amp alternators are not an unusual upgrade - those guys might have some insight.

Good luck.

 

[Philstang]

Ok, my fuse may have been blown before the new alternator. Everything has been fine the past 2 months with the fan. The high speed setting would kick the volt gauge from 14 to 12 at idle, but at speed, the high speed setting had no effect.

Last Sunday, with stock alternator still on, my volts stayed at 12 on the interior gauge (regardless of the fan being on or not) and the battery light was on. This must have been when the fuse blew. (slow burnout of fuse?)

So, I guess back to my original question, should a 150-175amp fuse be used for my new alt instead of the 120amp?

 

[Philstang]

After calling the builder of my alternator, they suggested not using a fuse...

 

[jrichker]

After calling the builder of my alternator, they suggested not using a fuse...

Have them put in writing that they will fix all the damage from the electrical fire that a fuse prevents. I wouldn't wish that kind of ignorance on my worst enemy.

A 150 amp fuse should be good to protect your wiring and alternator. It is unlikely that the alt will ever see more than that in terms of continuous current draw.

 

[HISSIN50]

After calling the builder of my alternator, they suggested not using a fuse...

What did he suggest using? A ton of people have used slow burn fuses with success. That said, if he recommended a fusible link, that should work dandy.

 

[Philstang]

well, I put a 175amp mega fuse in line between alt. and battery with 4ga. Volts go down at idle but go to 14V with throttle. Is this a sign of a bad/going out battery? I had to recharge the battery last week...