Here in Australia there are only three common items to be found in every hotel and motel room - a bed, a Gideon's Bible, and the camera or i-phone charger from the last occupant.
We get calls daily from people desperate to replace lost charger. The variety of different batteries and charger blocks produced by the various manufacturers precludes having one of everything available at short notice. Indeed, some cameras have long outlived the production of their chargers.
The answer has been the Inca and the Hahnel universal chargers, They can be configured to stuff electricity into nearly all batteries - with some exceptions in the Sony range and in some of the newer Canon professional batteries. You generally just drop the AA or AAA cells into the tray or manoeuver the Li-on block onto the blades and let it go for an hour or so. We use 'em all the time here in the shop.
If you just need to do AAA's scoop a couple of the INCA chargers out of the $ 1.99 bargain bin near the door. There are 4 batteries in there as well as the charging block, and the charger doubles as an LED torch or power block for USB devices. $ 1.99 - you couldn't get a punch in the eye in a waterside pub for that price.
If you need to power something up out in the bush and you have your motor car nearby, you can put a can inverter into the drinks holder on the center console and plug in the Powertech can-size inverter. It can put out 150W steady or 450W at a surge. it also has a USB port to power up tablets. Mind you, if you need to take a lot of tablets in the bush, it is time to slow down, watch the flowers, and smell the bees...
