frying alternators

[ShadowMan]

This is the second time I've replaced my alternator in 3 yrs, and really probably only 3,000 miles. I'm in the military and deploy often and when I am home, I'm ussually workin on the car so it doesn't get driven very far or very long distances. S13 blacktop, 1990 fast back, optima redtop batt relocated to trunk with power wire inside the cabin, not under the car. I googled it and results were either shitty brand alternators, or voltage regulator issues. I just purchased a remanufactured one from oreilly's but I'm willing to bet it's my voltage regulator because my power fc reads 14.2-14.4 volts which to me seems high. Someone school me on voltage regulators and proper install/placement/use of them. I am searching but some of these explanations make as much sense to me as a football bat. Thanks.

[Agamemnon]

Sound like a symptom of sitting too long without activity. The voltage regulator is built into the alternator, and I would be willing to bet that companies that reman stock alts dont replace the regulators. With that being said 14.2-14.4 volts sounds about right.

[ShadowMan]

It has sat for 7 months at a time while I was deployed, but since my last deployment I have been driving it regularly for about 9 months. I did have to rebuild the motor about 6 months ago, but once that was finished, I got it tuned and have been driving it to and from work consistently. I just wasn't sure if the added length of the positive cable to the trunk is whats wearing it out. I know I need to add an inline fuse close to the battery for safety but wasn't sure if there was something that was common knowledge that I wasn't doing to keep the alternator from being strained too much. Should it have to sit again for a while, what would could I do to give it a better chance at surviving? Just disconnect it from everything? I still have a lot of reading to do on this forum so maybe I'll find it with a little luck. Thanks

[mistamadd001]

Hi dude. I know its an old post but thought I'd help you out. If the car is sitting around for so long are you having to jump start it to get it running again? If so the biggest problem on alternators is popping the diode which cuts the connection to the circuit when the engine is off. This can put extra strain on the alternator bushes burning out the mechanism. The best bet would be installing a battery kill switch in the cockpit of your car and before going on deployment killing the battery connection so it doesn't discharge due to phantom drain. Either that or instead of jumpstarting the engine try putting the battery on a charge cycle when you first get back from deployment. That way you won't chance popping the diode.

FYI 12v is rated voltage for a vehicle system. It is the ideal minimum voltage for the system to function properly. 14.0-14.8v is the charging voltage and is what your alternator should be designed to run at. A correctly built and installed alternator should run about 13.8v at 850rpm. The most important thing for you to keep an eye on when running the car is actually amps to ensure you are able to run all York goodies the battery/alternator combo should be able to output about 100 running amps and around 350-400 cranking amps (startup).

If you're unsure how its running turn everything on (a/c, stereo, foggies, internal lights and headlights) then sit at idle turn your stereo up and check for light dip (the lights getting darker when bass kicks in yo) many big stereo boys do this to check that they don't need a capacitor for their subs.

Hope this helped.