I converted a LC+ Camelback to battery power, it was an interesting exercise and since there was just a simple addition of a battery, it was also easy.
LC+ Camelback Upgrade to Battery Power
Fun project, and I used it before I wired power to the tracks to test out all the routes on the new layout. However, once it was all wired, I had no more use for it, so I sold it to someone that wanted a battery powered locomotive.