[Pxtl]

I've taken the approach of electrical-taping my USB-chargeable 14500s each to a dummy-battery, since the things I put them in have 2 adjacent slots for series AAs. The voltage is still high (3.somethingV instead of 3V) but they seem to work.

[Dylan16807]

Are those LiFePO4 batteries that cap around 3.6V, or normal lithium ion that cap around 4.2V? I'd be cautious with either kind but especially with the latter.

[Pxtl]

They say 3.7v, so probably the wrong kind.

[sowbug]

That's smart. It's not perfect, as you say, but at least it's trying to play nicely with the other kids.