My West facing garage can get upto 120*F. Am I better off parking outside for the sake of battery life?
Hey, it has a warranty for either 100k or 150 thousand miles, I would not worry about it, enjoy the car!
A garage kept car is not a "creampuff," as it is always held in high esteem. Heat is a destroyer of all things electrical and plastice, including paint and batteries. I'd keep it outside under a car port, if you have one. For me, even when I have room in my garage, I keep my car outside and covered with a breathable car cover to protect the interior and paint from the sun. A car kept in a garage in the winter is bad, too, in that it goes through daily (if driven daily) freeze and thaw cycles. Water, as a liquid, gets into the cracks in the seams of the body, freezes and expands to cause damage.
Not everyone lives in CA or a CARB state. Since the OP didn't specify his location, we haev no idea if he's eligible for that on the HV battery.
I assume you take the car out of the garage and drive it on a mostly daily basis, so the hot garage won't have any effect on the battery. In the shelter of the garage it's protected from the damaging effects of sun, acid rain, bird droppings, etc. if its a really hot day, open the garage door a few inches so heat buildup is minimized a little.
I live in Austin, TX. No cover outside of the garage. Good point about interior temp when parked outside. Even with sunshade on the windshield and tint all around, the interior still gets pretty hot. I have not measured it to see which is hotter. I am taking some precautions. I opened the attic access door in the garage 1/3 of the way (probably breaking a fire code, LOL), and leave my garage door open a few inches in the afternoons, so the hot air can vent into the attic and leave via the ridge vent, and fresh air can come in. Car get driven daily so this is for the weekends afternoons when I am home. My main reason for garaging the car is UV damage to headlights. I just came from a 2002 Camry. The plastic lenses got yellowed in a few years and it took constant polishing to keep them in check. I slapped on some of these the day after I took delivery of the Prius. http://www.meguiars.com/en/automotive/products/g17110-headlight-protectant/
I just open the garage windows about an inch (so it's OK even if it rains, and I installed locks to maintain security) and put a small cardboard box in the attic access to hold it open a few inches. Then I leave a car window open when it's parked in the garage. The last part is to let odors (offgassing) dissipate. If you can find one, a small evaporative cooler will go a long ways to keeping things cool in the summer. Put it on a timer to run in the afternoon and refill it every day. In Austin, it is very rare for winter to go below freezing, but in places where it does often happen, you could buy an old Pentium 4 computer (or several if it really gets cold, or maybe a Britney or two if you can find some), install Folding@Home on it, and leave it running in the garage (back side facing the car) all winter long. If you're really into technology, you could have fun overclocking the PC, knowing that you'll be helping science while you maintain optimum storage conditions for your car.
The Pentium 4 (even a Prescott) is not that hot compared to a 6 core Sandy Bridge i7. The actual thermal dissipation of an i7 at full load exceeds that of a Britney thanks to Turbo Boost, even though the rated TDP is coincidentally the same. (Of course, the fact that an i7 is a lot faster than a Pentium 4 more than makes up for its high power usage, to the extent that it's considered one of the most efficient CPUs out there as of now.) Of course, buying an i7 just to keep your car from freezing is a little expensive (unless you have another use for it), hence the suggestion to buy a dirt cheap used Pentium 4. (Presumably, if you're that dedicated, you can locate your home office on the other side of a garage wall and route HDMI and USB cables through that wall to the PC. Obviously, that's silly and impractical in Austin.)
There is neither a Hot or Cold problem with the Prius, especially Parked, anywhere. The computers and electronic it's are protected to 350 degrees + The rule is when driving, if you need the AC, turn it on. The HV BATTERIES need cooling as well thru the fan(s) As long as your engine and inverter coolant systems are working, there is no problem. Don't do 85 MPH up Pikes Peak.
I do not know about leaving the attic access door open... my garage gets hot because of all the heat transfer from my roof/attic space above the garage to the garage. Even though I have the pink Corning fiberglass insulation in between the rafters, it doesn't do much to keep all that heat out. I have installed some photovoltaic powered attic vent fans in the attic space of the main house and I really should intall an attic fan for the garage as well. That will definitely help out the spare refrigerator I have in the hot garage to be more efficient and use less electricity. If you have a gable style roof you have the option of installing a gable fan to vent out the hot air that gets trapped in the attic above your garage as well. Lowering the temperature of the attic space will lower the temperature in your garage.
The open attic door seems to lower the temperature some. I put a wireless sensor in there so I can keep an eye on the temperature. Here is how I look at it: 1) If the attic is hotter than the garage, no air flow will occur through the opened door, because heat raises. All the heat transfer through the ceiling is still happening, and I am no worse off; 2) if the garge is hotter than the attic, the heat will raise into the attic, and vent out via the roof vents. The hot air will be replaced by the normal air drawn in from the slightly opened garage door. I think my garge takes in most of the heat from the sunlight hitting the door directly on sunset. The thin sheetmetal door transfers in all the heat.
Yes, high heat is bad for batteries and all electronics. I keep a house room thermometer in the car under the bridge, so I can peek in at any time to check on it when I work outside. On the hot days I crack the windows open in the drive way under a shady tree. The dark color interior gets hot fast. I see 105 deg on very warm days. There is the warranty but I hope to go beyond that.
The Prius isn't that fragile, if hot garages damaged the battery Toyota would have had to replace hundreds of thousands of packs under warranty and the car would have been discontinued a decade ago!
Some type of active air-exchange is must. Here in Minnesota, the wind-powered vent fans very common. My mom does have a solar one on her house as well. The newest code here is lots of vents on the underside of the overhangs, to feed outside air into the attic so the vents on the roof can easily pull it through for cooling. Houses that suffer from being too hot (often contributing to ice-dams in the winter) is inadequate input venting. The home/garage is much better off when the attic isn't struggling.
I've spent the last 5 years in southern Arizona, in a 2004 Prius (Nov. 03) with 254K miles, 8 and two thirds years on the Hybrid battery with no problems. This car has been garaged the whole time. My garage doesn't get much above 100 degrees during the summer months. This battery still takes about 300WHr to fully charge (40%).
Have you actually measured the temperature of the battery itself, rather than the air temperature in the garage? You might find that the battery is not a hot as you think because the battery is at a lower level than the air being measured. You can measure the battery temperature with a noncontact infrared thermometer such as this one: Non-Contact Infrared Laser Thermometer
