Heat preventing system boot...
I have a CarPC in my trunk and with outside temperatures in the 90s(f) my PC will not even attempt to boot. I have to fold down my rear seats and blow A/C back there for a while before it will boot. The computer case in fact is near scalding temperatures. I haven't used a temp probe on it yet, but I'd guess it's 130 or so. I have gone into the trunk and tried to turn the PC on when it's this hot and the CPU fan comes on for less than a second and then immediately shuts off. My assumption is that the motherboard is preventing boot because of the temp. Other people have noted errors or crashes, but mine just does not attempt to boot.
I'm interested in what others have had to do for their PCs to boot in this kind of heat.
I've searched for the past couple days and haven't found a real solid answer, although I've read about several people having the same issue. The discussions always get side tracked though on overly complicated cooling setups that only work with the computer running. Like big heatsinks or water blocks. Once my PC boots, the stock heatsink brings the system to a perfect operating range. What I need is to cool the PC BEFORE it turns on. Or keep it at least a little cooler while it sits in the parking lot so it'll boot and let the stock fan and heatsink do their job. I don't need the trunk to be comfortable, I just need it less than boiling.
The other discussions I've found all have some variables that confuse the issue and so I want to set some global variables to work from.
The question is how to make sure that the PC boots after sitting in a parking lot all day in the sun.
1. The car is stationary
2. The temp outside is 110 degrees F
3. The car cabin temp is 125 degrees F
4. The trunk (boot) temp is 140 degrees F
For the purpose of brainstorming, I'm not worried about running down a battery because I can control this with shut off switches or something that turns itself on and off instead of staying on constantly. That is a seperate hurdle and can be addressed easilly with low-tech means. (such a device like a battery buddy - a DC power monitor that triggers a relay to shut off the power drawing device)
Re-directing A/C to the trunk or using fans to move air between the cabin and trunk are ideas that require the car to be on or require the cabin temp to be conditioned first. In the first several minutes after getting into my car the cabin temp will be far too high still to use as a cool air source for the trunk. And while I could use A/C to cool the trunk after I start moving, I'd have to wait until the trunk cools and then boot the PC manually instead of the power controller doing it for me. This is not much different than what I do now, so why do anything if that's the solution?
Maybe my system would boot at 125, just not at 140. Maybe making the trunk temp equal the cabin temp would do the trick. Has anyone actually just vented to their cabin and had that work?
A temp probe and a hair dryer to test operating temps will answer that question scientifically, but for now the assumption is that the cabin temp is still too high to allow the PC to boot.
My searching has come up with 3 basic ideas.
1. Vent trunk to cabin - this idea sounds like it has a small chance of working. But if the cabin temp is still too high, then this effort will have no effect on the problem.
2. Vent trunk to outside - this idea has the same drawback as #1 if the outside temp is still too high or the air is just too hot to effect the trunk air temp enough. Pumping 110 degree heat into a 140 area won't drop it to 110. It'll be somewhere in between and probably still too hot to boot.
3. Peltier cool the trunk - this idea presents some complicated challenges in fabrication, but people get stuck on a condensation issue with this and even the A/C options. However, condensaton is only a problem if you cool down to a dew point. That's far from what would need to be done.
Consider the fact that applying a small amount of 50 degree cool air to the trunk via a peltier would NOT bring the trunk and PC all the way down to 50 degrees and therefore produce condensation on the PC parts. It might however drop the 140 down to 80 or 90. And that would be a temp that I could boot at for sure.
Condensation would form on the peltier itself for sure. But I'm not talking about puting the peltier on the CPU or in fact anywhere close to the PC. The peltier would be up in some corner like a fan on a shelf next to your desk at work. It would produce cool air and just blow it towards the PC, while a vent fan vents to the cabin maybe so as to complete the air path.
This does present two challenges though.
1. Dealing with the hot side of the peltier - this could be dealt with by mounting the peltier in the lid of the trunk with the actual heat side of the peltier (or just it's heatsink) outside the trunk. This would entail cutting a hole all the way through the trunk and making some kind of mount for the peltier where you end up with the heat side external and the cool side internal. Doing this safely and cleanly are side issues, but I think it could be done well with enough thought.
2. Dealing with the condensation inside the trunk. Simply mounting a catch tray with a sponge should be sufficient to catch the drops off the internal heatsink for an 8 hour period (or certainly for a 30 min period if you use a timed turn on) and the sponge can be wrung out every night or something if it really gets that wet. Catching the water in this way will prevent to some degree the trunks overall humidity as long as the sponge is inside an enclosure with only a small part exposed to catch the drip.
My other thought for the condensation might be simply mounting the peltier in the floor of the trunk and making a second hole for a drain so the water simply drops off the peltier and down the drain onto the pavement outside.
Even if a safe and clean install could be done this way, power is then the issue. How long could a car battery power a peltier? Only real world tests will find out for sure, but even if you could get 30 min out of it, surely that would be sufficient to cool the trunk to under 100 degrees. Remember the goal is just to lower the temp enough to boot, not to make it comfortable in there. A timer could turn on the peltier every day 30 min before lunch and 30 min before I go home. Then only run for 30 min and shut off to protect the battery.
Thoughts? Suggestions? Anyone actually had the same problem and have it fixed now?
Thank you in advance!