A PCC battery should far outlast the e-cig batteries it is constantly recharging. The e-cig batteries are under a very heavy current draw each and every puff you take, which is why a typical e-cig battery only lasts for 200-300 cycles. But the PCC batteries are only used to charge other batteries which doesn't strain the pcc battery with high current draw, so they should last quite a while. Very possibly a few years.