I use this Bluetooth keyboard sporadically with my phone and tablet. It uses two AA batteries that technically should last six months with normal use; 12 months on standby. I've never tested that as I got the solar hacking kit from Uncommon Goods and went about trying to figure out where the hell I was going to install it. The keyboard ending up being the place, even though I had to literally hack a hole into the battery compartment and secure everything with packing tape. Plus, the panel is hidden under the keyboard, meaning I have to flip it over to recharge the two Eneloops I threw inside.