On Monday, January 29, 2018 at 9:14:51 PM UTC-5, wrote:
Yes you can!
But buy AA Nimh types 2500 mah each or 3000 mah get 10 just install like any battery case.

The highest capacity cells often have the highest self-discharge and early failure rates. I'm much happier with 2000 mAH low-self-discharge cells, such as Sanyo Eneloop. Especially for devices that are used occasionally, it's frustrating to pick it up when you need it and find the batteries went dead.

Don't know whether you can get low-self-discharge NiMH cells with solder-able tabs though.

Another battery type I've been experimenting with are AA-size 3V Lithium Iron Phosphate (LiFePO4). Paired with dummy cells (since they are 3V each) they are a very lightweight and low-self-discharge alternative for occasionally-used devices such as headlamps, cameras, etc. As long as the device uses an even number of AAs. These cells need a special charger, and I would charge them individually and not in a pack. Their capacity is lowish, too, about 600 mAH - similar to the capacity of NiCads, but at about 1/3 the weight.