I was just wondering how exactly you would go about installing a 2nd battery.

Is it safe to run two batteries off the stock alternator of the 92 SVX?

If so;
-should I connect the batteries in series or hook them both to the alternator in parallel?
-what gauge wire should be used?

In case you're wondering... I was planning on putting the 2nd in my trunk to power the stereo. I've been having electrical problems ever since I installed it. Lights dim, and the car doesnt get enough electricity to start unless I turn every appliance off first. I know i could get a capacitor, but I'd rather know how to install another battery.