I have a TPMC-10 that has never been used on a job, although it sits on my desk. Has been pretty much constantly on the dock and rarely used. If you interested in pickup up a whole unit / spare, let me know, I would like to sell it, as I don't really need to test TPMC-10 programs anymore. I can run a battery test if you like, turn off the sleep function and see how long it lasts.