Lead-acid batteries, even when in use, generally have a lifespan of ~2 years. As they get old, sulfur crystals build up on the plates inside. As more of the plates are covered, they will have difficulty holding a charge longer As such, we highly recommend you replace your PUP battery every ~2 years or once it is unable to hold a charge, whichever occurs sooner PUP 7AH: for PUP 500 and PUP 700 PUP 9AH: for PUP 1500 and PUP 3000
