what you definitely don't wanna see is a several volt drop or rise. either one is dangerous. that probably means you have a short, and bad things happen with shorts. you're a little safer with an 18650 IMR than with most other bats, as they can handle a higher current draw, but definitely multimeter your stuff first, always worth it. if something doesn't seem right, it isn't. i've worked in low voltage circuitry for years and i can say without a doubt, don't risk it. the risk is relatively low in this application, but still, better safe than sorry. i've seen the worst, and i was several feet, not inches, away when it happened.
