Alternator on/off switch question.

[sully06]

Thinking about doing this. Will that sudden "spike" of electricity when turning the alternator back on damage anything? Seems like it could. Thanks for any help.

[GhostWolfGT]

Shouldn't be a spike above 14.x volts. Its regulated. Houses are not. So when there is a power surge it ruins electronics. The belt may squeal when the alt suddenly turns into an electromagnetic brake trying to top the battery off. I've done this at idle but never at higher RPMs. I have, however, had a short where my alt cut in and out without any adverse affects. Voltmeter bouncing from 14.3 to below 12 then back.

Also keep in mind that some cars won't run with the alt disconnected without other modifications. Test that before cutting wires and installing a switch.

Edit: Also, since I've never tried this maybe someone else can answer. Does it even help without having solar and deep cycle batteries? Seems to me like the extra load charging the battery back up would cancel out any benefits. Unless you disconnect on pulse and charge on glide. But I also believe this would prematurely destroy a regular battery.

[Daox]

Correct GhostWolfGT, you need a deep cycle and some other form of charging to make an alternator switch useful.

I've installed alternator switches on a couple cars. I've never had problems with spikes killing any electronics.