I personally run with these.
Unfortunately OOS. But, these batteries are abundant at Amazon. You can find other vendors in Amazon selling this kind. This will run in 1.5 to 2hrs.
These are known as RC battery.
This is enough 99.9% of time for me since I also have generator.
I also try below for my testing. With Lion battery, you can get about a day use.
You can find cheaper one. You need to get 18650 battery holder and Plug:PH 2.0 Connector. To save some money, make sure you find the unprotected battery. The sensor has LIPO/LI-On battery protection already. I think it should work with double protection. I just never test it. I just think why have similar battery protection in parallel. I do not like this solution since It is bigger. If you put it inside a case, this is a reasonable solution.
Just a note on the connector. Battery connector is not standardized. Please make sure that the polarity is correct before you plugged it in.
I hope it help.