My warranty book says "original equipment battery" warranty is 24-mo. and unlimited miles.
Mine still working at 4+ years. I checked with a battery load tester and it tested weak. Easy decision to replace.
Found a replacement at Costco; Interstate "fitment code 39" Group "121R" for $100. Local Costco had to order it for me.
Odd that Amazon does not offer this battery.
However! Amazon did list battery for my 2010 Prius (ACDelco, made in Korea) and did deliver free; no hassle. And more odd, Costco does not carry battery for my Prius ?
Thx for comments.
'15 Soul EV+, '10 Prius