Lithium batteries
Like everyone, I use batteries (AA or AAA) quite often. My biggest consumption is AA — the thermal actuator heads devour them. There's a solution of course: Varta makes a lithium version. It's outrageously expensive and if you have multiple actuator heads... it adds up fast. This year a Kickstarter newsletter landed in my inbox about ongoing projects. One of them was Linogy — lithium, rechargeable batteries. A dream! I use Eneloop from Sanyo/Panasonic. However, those only output 1.2V which is sometimes not enough, and they're NiMH. I backed the project and waited. In the end there were quite a few of us.
My package also included an adapter for AAA batteries — a very useful and practical thing. You put a AAA battery inside it and you can charge it normally in an AA slot. The USB-C charger is very convenient and once a battery is charged it pushes it into storage, so you have a clear view of how much you have available.
If you'd like to try Linogy, ordering through this link gives you 10% off your first order. 
