What do you guys carry around in your vehicles?
Right now I have a zebralight SC600 in my console that is my edc at work and a X10 in the console as well.
Nothing with Lions for me for fear of a heat explosion.
I carry a 6D mag with a junk Terralux LED bulb. A 501A with a Solarforce low voltage XPG 3 mode drop in CR123 powered. A Match mod Mini mag low voltage single mode XRE powered by two AAs an X-2000 zoomie 3 mode with a crazy strobe and an Ultrafire headlamp strap that fits all the lights except the 6D mag.
I've heard this before, but has it ever happened (from heat, in a car)?
I have numerous single and multi li-ion torches in my car all year long, loaded with 18650's with no issues. This is a black sedan, during South Carolina summer...yep, it get's hot here.
(Disclaimer - I do drive crappy vehicles, so if there was an issue I wouldn't be too upset. Actually, I kind of look forward to the story! "So Tim, what exactly happened to your car? - Flashlight blew it up!" )
i don’t want to lose 90% of the battery capacity in a year so i carry the cyclone c88 on me
I usually carry several 16340/18650 p-60 lights (mostly solarforce) in my van and truck along with extra batteries. I keep it under the drivers seat where it is somewhat cooler than the rest of the vehicle. Every few months I take them out, check them and usually top off the batteries. So far no problems with anything which is surprising because it's always hot a f**k here in paradise. 
That’s good to know thanks,I have to deal with –20 cold in the winter also. I wonder how a lion would handle that I guess I’ll stick an unloved P-60 light in there with an 18650 and see what happens.