What is the estimated battery life?

Our standard battery pack is comprised of lead-acid batteries, and are rated at 1,000 charge cycles. So, if you are running the batteries down (driving full range) and charging them full daily, that amounts to about 3 years. We estimate typical usage will result in closer to 4-5 years, which is comparable to the expected life of a normal car battery. The extended (80-mile range) battery pack upgrade uses lithium-ion batteries, and those packs should last 10+ years.