I just received my first light that doesn't have an aluminium body. It's an iTP A2 E0S SS. It's a solid little sucker and seem to be well built. My question is this. Will I ruin this light if I put a 14500 battery in it? I'm guessing that's a no no but thought I would ask.
Li-ion will not insta-poof the light, but will damage it with extended use.
The stainless body is part of the problem - it doesn't transfer heat away from the critical area as fast as aluminum, and this allows the LED to 'cook'
Even thought the aluminum version will run on a Li-on, it is not approved to do so.
Same issue with my Olight i2. No warranty coverage if you run Li-On's in it.