Upgrading to a 250 amp alternator
Yes run a bigger wire to the battery from the alternator.
I'd run at least a 1/0 gauge for that many amps.
I would also upgrade the ground from the battery to the body, the battery to engine is already a pretty good sized wire and will do fine but some people like to upgrade that one too.
I'd run at least a 1/0 gauge for that many amps.
I would also upgrade the ground from the battery to the body, the battery to engine is already a pretty good sized wire and will do fine but some people like to upgrade that one too.
TECH Fanatic
Joined: Dec 2017
Posts: 1,469
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From: Bossier City, Louisiana
If whatever you are actually running in the vehicle will ever demand 250 amps of current then yes, it'll need to be a 250 amp fuse. You MIGHT be able to get away with something smaller if it was a slow blow fuse but . . . I'd stick with a 250 amp fuse.
250 amps??? At 12 volts? That's 3000 watts of power. I'm guessing a VERY large stereo?
Rick
250 amps??? At 12 volts? That's 3000 watts of power. I'm guessing a VERY large stereo?
Rick
TECH Senior Member
Joined: Jun 2016
Posts: 22,298
Likes: 3,619
From: Central Cal.
If whatever you are actually running in the vehicle will ever demand 250 amps of current then yes, it'll need to be a 250 amp fuse. You MIGHT be able to get away with something smaller if it was a slow blow fuse but . . . I'd stick with a 250 amp fuse.
250 amps??? At 12 volts? That's 3000 watts of power. I'm guessing a VERY large stereo?
Rick
250 amps??? At 12 volts? That's 3000 watts of power. I'm guessing a VERY large stereo?
Rick
I put an underdrive pulley on several years ago and when I turn on my bottle heater at idle the voltage meter is in the red. So I probably went overboard on a 250 amp alternator, but I wanted to make sure it could handle the bottle heater. The bottle heater draws 14 amps.
You are going to need:
1/0 ga from alternator post to positive battery post with a 250a fuse in-line
1/0 ga from alternator chassis to negative battery terminal
I also ran an extra 4 ga from the negative batt terminal to the block ground on the pass side, as well as a 4 ga from the drivers side of the block (where the ancillary bracket for the factory alt bolted on) to the chassis ground on the drivers side frame rail (on the factory, this has a small ground strap bolted there)
Out of curiosity, what brand alternator are you going with?
1/0 ga from alternator post to positive battery post with a 250a fuse in-line
1/0 ga from alternator chassis to negative battery terminal
I also ran an extra 4 ga from the negative batt terminal to the block ground on the pass side, as well as a 4 ga from the drivers side of the block (where the ancillary bracket for the factory alt bolted on) to the chassis ground on the drivers side frame rail (on the factory, this has a small ground strap bolted there)
Out of curiosity, what brand alternator are you going with?
