When should I replace my eBike battery?

Lithium eBike batteries typically last 500-1,000 full charge cycles before capacity noticeably degrades. In practice, most batteries last 3-5 years with regular use. Signs it's time to replace: your range has dropped to 60% or less of original, the battery doesn't hold charge reliably, or it runs very hot while charging. Replacement batteries cost $300-$800 depending on brand and capacity.