Some rechargeable N-Cells I have used in my 41c over the years

[Dave Britten]

I've used these on my 41 with pretty good results:

https://www.amazon.com/Tectra-Rechargeab...B096FJKDX3

The 4-pack comes with a single charger, so you have to charge them one at a time, but they're not exactly high capacity, so they charge pretty quick. Alternatively, buy two 4 packs so you get two chargers, and have a spare set you can alternate with.