I might have mentioned it in passing before, but for those of you that use hand controllers in VR, I found these Tenavolts AA 2775 mWh rechargeable batteries to be fantastic. My WMR controllers are huge battery suckers, but these things last a long, long time between charging. I caught them on sale for 2 units (8 batteries, 2 chargers) for $25.99 during an Amazon sale, so you might want to wait until the price drops on them.
https://www.amazon.com/TENAVOLTS-Rechargeable-Batteries-rechargeable-electrical/dp/B07HQ7QV7W
Here is a nice teardown and review…I don’t know why I watched this whole video, I just found it very interesting for some reason…