So far, I haven't had some of the the problems with failure to charge (or to hold a charge) that other users describe.  I charged it for 10 hours, and on our first off-grid reunion, the pump inflated four queen-size air mattresses and a 9-ft vinyl raft...after that, it was out of juice.  I thought that was less-than-stellar battery performance...but it was reasonable...sort of.  That being said, I have a bunch of other issues with this item: