You can charge Lithium Ion batteries with max voltage (8.4v, 4.2v/cell) to give you maximum usage time, or you can charge to 90% battery capacity but maximise battery life using 8.2v (4.1v/cell). I went for the max life strategy for Mojo, so the charger never exceeds 8.2v. However, on the rare occasions that Mojo battery fails, it's generally because it was left on 24/7 and with the charger connected. We early on changed the advice, so that when you run it with the charger permanently connected, to turn it off when not in use. Then the battery gets charged to 8.2v, then the charger turns off, once the trickle charge phase is gone. If you leave it on, then the charger permanently is in trickle charge mode, as the trickle charge feeds Mojo, not the battery, so the battery is permanently having an applied voltage - which can degrade life - even though it's at the safe voltage of 8.2v, not the maximum 8.4v.