1 wire or 3 wire alternator sbc (1 Viewer)

[Snakeman187]

just checking before i make a purchase for 100amp alternator the 3 wire is if you have a external voltage regulator and the 1 wire is when there is a internal regulator? let me know if i am way off base. im thinking a 100 amp should suffice for just a couple of hella's and 25 watt receiver deck. any input is appreciated if you have other recommendations.
thanx

 

[Pin_Head]

Off base.

All GM regulators since the mid 70s are internal regulator. The extra two wires on the 3 wire alternator are a key on / idiot lamp wire and a "voltage sensing" or reference wire.

Read up on it at frequently asked alternator questions

 

[kc_chevota]

rule of thumb is to add up the total current everything pulls and then doubble it, as you dont want to run the alternator at max

 

[nat]

GM alternators will have a built in regulator.

I think running 3 wires is better, as it gives you a battery idiot light (which can be useful) and it energizes the alternator so it is charging right away at low rpm's.