Generally when I need a battery, this is where I come now. It's a small store, so they don't have everything on-hand. But odds are they can order it for you. On this occasion I needed to replace an old Macbook battery. No, they didn't have it, but 'yes' they could order it. And, believe it or not, they were cheaper than the prices I found online! Took a week to get it, but I have it installed and it's charging now (I'm on a different computer...I'm going to go to full charge and then full discharge once). I routinely get my gate opener batteries here too (lead-acid).
I'm happy with them thus far.