just to note, it may be possible to replace the batteries at a future date, two of these for example, if wired correctly, could give off the same voltage and have the same mAh rating(therefore the same power rating as well), I don't know if the charging circuitry is compatible, which could lead to explosions lol, but it may be worth a try if the batteries completely fail(I'll probably do it at that time, and if there is still a community I'll be sure to report results!).