Maybe this is a bit of a necropost, but I think a laser being killed by a "backwards battery" is just piss-poor design on the part of the manufacturer. I would go so far as to call it a defective or negligent design, due to lacking a basic protection component, or failing to anticipate basic user error, or both.
They've never heard of a blocking diode? Really?
They've never heard of somebody accidentally installing a battery backwards? Really???
BULL. Lack of reverse protection is bad design, period.
Even my cheap, 15-dollar Ebay lasers have reverse polarity protection. A company selling these for 100's of dollars a pop has no excuse. Obviously the company is penny-pinching and corner-cutting, in omitting such a basic protection feature from such an expensive device. If I spent hundreds on a laser and found out it could be killed by something as idiotic as a backwards battery, I would probably not do business with that manufacturer again.
Just my thoughts; if these lasers really do lack reverse protection then that is a shame, and the people who bought them deserved better for what they paid.
Dunno what they do inside their hosts; but in the bare module I ordered from them long ago it did have a diode attached to the back end of the module... which how I understand it, that's to prevent a backwards battery :thinking: