44g/1.5oz Sanyo USB Battery Charger

Can you charge 1 batt at a time ?
(my AA/AAA can only do them in pairs)

You have to do them in pairs. I don't believe I've found a charger that will do one at a time yet. I think that would require some kind of fancier electronics to switch between charging one or two.

KJ

Ok, thanks for that.

ccrane has a charger that can do one at a time http://www.ccrane.com/more-categories/batteries-chargers/cc-quick-charger-2-batteries-and-car-adapter.aspx#prodDetails

It has no weight listed. $40

Maybe you could remove the electronics and rig something up that was lighter

Got mine last year on Amazon, was about ~$18 with two AA Eneloop cells.

Charging via USB, even from a desktop PC, takes a looonnnggg time. Can't imagine how long it'd take hooked up to even a quality, portable, solar panel. Although I love the idea, I gave up on solar panels for lightweight backpacking a long time ago. Spare cells are still lighter, even rechargeables. That said, placing a dummy cell in one slot will force twice the current into the remaining cell which is normally a no-no. But if using a solar panel, and if it can provide enough current, then that one cell will charge faster. YMMV…