"Because the Chevy truck uses a moving iron style ammeter, it has a much higher "raw" FSD (I measured 40 amps on mine with the needle hard over but not pegged), so a shunt with around .33 ohm total resistance still allows the meter to kick over without in pegging with a 63 amp alternator. I think I would go for a .25 ohm shunt if i was using an 80 amp alternator though."
Hi there,
Can anyone share a specific formula for determining the shunt requirement of an ammeter? I'll be installing a 100A alternator in a '55.1 Chevy 3100, as well as a 75A in a '58 Buick shortly, and I'd like to keep the original gauges and not risk burning anything to the ground. Thanks.
Ed K.
Ithaca, NY
