Run another battery on Alternator

[AlexWall]

I have a Hyundai XG350L and it has a stock 120 amp alternator and I was wondering if I could use that to run an extra battery in the back of my car to help my amp out.

[Neckbeard]

ehhh...IF you did that, your alt would be working its self to keep both batteries charged, Would recommend getting a bigger alt, then another battery

[wccfan12]

I ran two C&D 54 ah batteries (under the hood) off my stock 120 amp alt for months with no problem, now granted I have a tenney 320 amp alternator on the way now, but it shouldn't be too bad as long as you're not draining the batteries to much or dipping too low in your voltage. Now like Delfold said, you should get a bigger alt sometime down the road, but you shouldn't have to right away unless your car is really old.