Hi Sharkbite
I also have an LX90 and very much like your idea. When I search "26650 Lipo batteries" most of what comes up refers to Li ion batteries. Such as in the link below.
Are you confident that you have LiPo batteries? If so, do you have a link?
https://www.jaycar.com.au/26650-rech...ipple/p/SB2315
Philip