I have a 93 civic with a 70 amp alternator. Right now the alternator is producing too much voltage( up to 20 volts) I suspect that my 900 watts rms stereo system(mtx tc 4001 front chan. @ 4 ohms rear chan. @ 2 ohms, mtx mxa6001 A 2ohms) is to blame. So I decided to get a HO alternator, but the closest guy that does it is in brampton a few hours drive. After doing some homework I found out that added a second isolated battery may provide better protection. Does anybody have any advice, pros or cons and what would you do? HO aternator, Second battery or both? I have already upgraded my battery and wireing for those who will ask.

 

I would get your alt fixed first. Charging at 20v will toast the battery within minutes.

 

yeah i know it's an intermittant problem, so I've got a little time. on vacation too so I can use the GF's car if I have to. There doesn't seem to be a trigger for it either. sometimes it does it right away sometimes not at all. I only noticed it a couple of days ago, and trying to save some money. I can get a new one for about a hundred bucks, have the old one remand into a HO for $175 or buy a HO for $275. But I'd have to drive down to brampton for the HO cause I havent found anyone reliable here(oshawa,whitby,ajax etc)