Automated heater box project

[jangell]

Before building anything new (especially displays and processors) into a car you should verify that the temperature range (stored and operating) is appropriate to an automotive environment. -40C to +90C seems to be a common automotive interior spec. Although for use in a "classic" car, -40C is probably more extreme than you need to worry about. -15C is probably good enough for a garaged car.

I wasn't too concerned about the cabin temperature and the operating range of most of the parts. However, your comment made me realize that I plan on running the laptop with the lid closed. That will increase the heat even further, and in a hot car will probably move it outside of its safe temperature range pretty easily. Even on a desktop a closed laptop can have overheating issues.

I was looking at a laptop because of the built-in battery and natively low power usage. Macs have a nice sleep feature that goes from sleep to wake in just a few seconds, so it can operate in a very low power mode (there are other reasons I'm using a Mac from a software development perspective). I may have to consider a Mac mini instead, which can be more easily cooled and will take up less space in the car, but will require an external power supply at all times. I mean, I was going to add another battery anyway, but with a Mac mini I'll have no choice.

...of course, a quick search shows that the official operating temperature range of a Mac is 50 F to 95 F (storage range -40 F to 116F). I expect it can work for a bit outside of those ranges, but I might want to rig up something that detects unsafe temperatures and turns on a small electric heater in the winter and the blower motor in the summer if necessary. At the expense of my secondary battery, of course. For the cold, the issue appears to be condensation as temperature increases, which could short out the electronics. There's probably some clever way around this.

LCDs can also freeze and crack in extremely cold weather, although hopefully it won't get THAT cold in Massachusetts. I've seem the LCDs in my Subaru take a while to switch states on very cold days until they warm up, but they haven't broken yet. I'd assume that Subaru is using hardware that can take those temperatures, though.

I plan on upgrading the equipment over time, so occasional failures on non-critical systems (ie: the car won't crash) like shouldn't be a huge deal. Hopefully...

Thanks

-- Joe