Second battery, I gotta get one
 

....

duralast?

....

oh, well im a tard..... go with at least 650.. high you can go, the better


where is your black alero now?

last time i heard, you need to get the exact same battery. you can't (shouldn't) mix types/sizes/CCAs

....

really.....

so a 600 with a 700 will explode, i think if you travel upwards in cca you will be fine, no overcharging

....

i doubt it'll explode, but it will impact charging capabilites/retention

if its audio causeing it why not just get a capicitor??? way cheaper

....

caps functionally do nothing but even out the flow of power, and even then its minimal. save your money and don't get them.

I had a friend who mixed batteries, and didnt have any trouble on his truck. What he did was lead the + from the OEM battery to the larger Yellow top battery, and from there he wired the sound system (no battery isolator). This actually solved his dimming problem.

I'd get a diode isolator.. will 100% solve your dimming problem.

Your alternator charges both batteries, but you have the car running off one, and the sound system running off the other, and there are entirely isolated from eachother via two big diodes.



If they're connected in parallel, supposedly any small charge difference will lead to them charging and uncharging each other constantly, which will lower the life span.

You can get a relay type isolator, instead, but all that is is a big relay that disconnects them when the car's off, to prevent the flow between them. Seems like diodes are a better way to solve the problem.