probably -20 to +35 outside temp, no idea how that translates to car temps with windows and all that. I just don't like keeping normal lithium ones in case they would catch fire, also this light would be put there and probably forgotten for a few years..
I was specifically questioning vadimax but interested in responses from anyone.
Are you talking Celsius?
Where I am there's no way I'll see -20 (Celsius). I'm not experiencing anything (in winter) much below 10 degrees (usually at night) unless I travel a decent distance.
I will frequently see temperatures of around 35 degrees (Celsius) over half of the year.
What temperature do you think lithium batteries stored in a light are going to catch fire (lithium primary/liion rechargeable)?
I've read on here talk of this, can't remember specifics, but from memory it took some serious heat to make them combust.
I gave an example of a recent ~40 degree day, must get to around 60 in a parked car on a guess.
Some of the electronics on the car (front collision management camera) shut down due to temperature (it's located at the top of the windscreen in a cluster of various sensors). It was a hot day for sure.
My 2x18650 light kept in the door pocket was fine.
That said I'd be concerned to leave it on the dash baking in the sun at such temps. I'm sure that would dramatically increase its temperature vs being tucked down the side of the seat in the door pocket. I would never do this for several reasons.
I really don't think there's a serious risk of my light exploding kept in its location in the car even though there's frequent high temperatures. I've been keeping this light there for four years now.
I can understand why people may not be comfortable with keeping a light under certain conditions. Discretion and common sense go a long way.
On another note, I've got a couple of lights with fairly silly power to weight ratios. I feel much more risky running them on full burst with high battery demands and high temperatures compared to keeping the light I keep in the car.