I know all to well from leaving batteries in my higer powered laser pens before, I'd rather not kill my sabers in such a manner, I do have a question though...
I have 2x Li Ion rechargable batteries which deliver a decent 3.7v each @ 350Mah, could I wire one of the three battery slots pos to neg, and fill the other two slots with these batteries creating 6-7v @ 350Mah for the saber. would that fry it, I'd really like to know the circuitry limits and requirements before trying it out, I already read above that mixing batteries is a bad idea so ill avoid that at any cost! but if my idea works then i think its easier for me and less costly too!