I have 2 aftermarket excallibur nihm batteries from the guy that sells them on %$^ . They lasted less than 2 years . Im thinking some cells are good , others not . Has anyone ever taken 2 battery packs apart to rebuild 1 good one , by voltmeter testing and resoldering good ones ? What is a good after market long lasting battery for the excal ? Where do I purchase ? Are they Lithium ? - thanks