Build My 40 Build... 20 years and Counting... Purists beware, this may hurt... :D

[bikersmurf]

I like more amps.

I’m most impressed with the 102 amps at idle. Unlike my triumph, before I upgraded the alternator, I’ll be able to have the headlights, wipers, heater, and radio on while sitting at a stoplight. Also no high idle will be needed to charge a battery well.

 

[bikersmurf]

Because I barely know a thimble full of information about the use of higher amperage alternators…what year is the truck? I had read if you go 25-30 amps higher than my 1975 dash cluster can deal with, it runs the risk of screwing up the gauge and possible wiring … I could REALLY use more amperage. While I’m driving with the in-tank electric fuel pump for the Sniper, the gauge is usually 1/2 way or more to the +30 side. Before the Sniper, a slight needle width over “0”+. I realize the replacement of power is what’s causing the draw and I wonder if the draw would exceed the replacement over time…I also have a winch but not connected

I read @Coolerman dissertation on the subject but it still flies a bit over my head

Is your fuel pump wired to the battery or the fuse panel?

If battery, the ammeter will show its load as “charging” the battery. Not really a problem, but it does reduce the usefulness of the ammeter.

Normally the load on the negative side of the ammeter is offset by the alternator output (also on the negative side). The battery is connected to the positive side of the alternator. If the battery is being drained the need moves towards the “-“ if the battery is being charged, the needle moves towards the “+”. Once the battery is charged the needle should sit very close to the middle. If you’re draining more power than the alternator pots out, it’ll move towards the negative side. Do this too long and you’ll have problems.

Back in the beginning, I had 2x 100 watt high beams, and 2x 100 watt “driving” lights. They were DOT approved headlights, With all 4 on and the running lamps the alternator couldn’t keep up, Eventually they would drain the battery if I left them all on. So o wired things up so I could turn off the tail lights off highway. The 120 amp alternator eliminated the issue permanently.