If you do decide to go with SLA, I would recommend the B&B EB 20 - 12 AKA the EB 12v20AH . EB stands for "electric bike" so they are specifically made for it. I've read comparisons on SLA's and the EB 20-12 gets 5 AH of usable capacity more than the other regular 12v20AH batteries. In other words, you'd be able to go 5 to 10 miles more on the B&B EB 20-12 than other SLA's.