I think I've found a good way to cool the whole car during the summer. A 12v solar powered fan placed in the rear bumper above the license plate.
The solar powered fan is on ebay. The solar panel could be placed anywhere. You would need the two peice system.
The fan would be placed in the rear bumper. There is a nice huge opening above the license plate that would be perfect for the air exhaust. Ideally you would need to cut a small vent in rear storage bin. The lid would also need to be left open. Though I'm sure air would still be sucked out if the lid was closed because there is plenty of gaps around the battery compartment.
Second ideal for fan would be to insert the fan into the cars vent system. This would allow use of the cars vent just below the windsheild.
Several different sizes of 12v fans can be purchased.
My 2 cents:
The need to monitor the battery temp with heavy MIMA use has led me to install a cheap indoor/outdoor thermometer in the battery pack. Brian has also installed one on his MIMA equipped Insight. It is easy to install once you get the covers off the IMA box. Warning! The screws holding the fan to the metal clips on the plastic shroud can be real tight, and the metal clips will twist and rip out of the plactic , so be sure to hold on to them with some vise grips while removing them. Once the fan is removed, you can reach in and tuck the outdoor temperature probe into the space between the side of one of the subpacks and the plactic holder for the batteries. Some white thermal transfer grease to improve the thermal transfer, and you will know how hot the batteries are. The temperature probe wires can be routed next to the reinstalled fan, and be careful routing them into the front of the car.
The battery fan shuts off when the car is in Auto stop for some strange reason, even when real warm, so that does not help the situation. I also noticed that there was a fair sized gap on the sides of the fan, and since the fan is blowing out of the box, the gaps will allow air to get sucked in near the fan, which reduces the air flow through the pack. I taped the gaps with black tape, and it showed a little better air flow. I am looking at placing a smaller fan blowing into the duct behind the passenger seat, to force more air through the pack.
The fan also does not seem to run continously, even when the pack is hot, so on the MIMA_C, I am tapping into the fan control relays, and I am putting the fan on at high speed whenever I sense the temperature rising to the 100 degree point. I have seen 117 deg on the batteries when the ambient was at 75.
Well, since this thread lives once again. It's going to be 110 here on sunday so this should be interesting. What you just said about the fan not running in auto stop (my god) somehow makes a lot of sense as to why I get insane thermal issues from time to time. So that gives me some incentive now. If I have issues with mine agian this summer I'll do the same and put a manual tap in to the fan control relays.
Also, I noticed that the fan used is a panasonic panaflo. If you happen to still have your box opened up could you write down the model number on that fan. I think they used the quiet one. If so I was thinking replacing it with their higher flow model should help also.
Knocking on wood... It's been in the low 100's the last couple of days and I haven't had anything happen yet...
02 Red Insight - Sold
06 Silver Civic Hybrid
92 Saturn SC2 Electric, Arizona Alt fuel plate "ZEROGAS"
Just happens I am starting to work on a temp monitoring project (while patiently waiting for release of MIMA_C dot1) for my insight this weekend using the indoor/outdoor thermometers. After doing some research on the meters it appears that most all of these type digital display / battery powered units have the same specs and sensing ranges so I deducted they must all be using pretty much the same circutry and soforth. I found an online source that had Oregon Scientific #EM899 brand on sale for 10 bucks each. These display both indoor and outdoor at the same time which IMHO are the ones to use since we don't need another switch to be having to flip back and forth. I bought several as I wanted to monitor intake air at the cat and also at the air cleaner: ambient and cabin temps: and in prep for MIMA I was thinking about the bat box as well. Am also considering a location in the tailpipe just prior to the back bumper, for kicks and grins. ( has been in the 90's here this week and after arriving home after my return commute of 40 miles I can grab the tail pipe bare handed, its body temp ) Anyway, Long story shortened you can take the thermistor that is attached to the pcboard desoder it and add length of wire to put it in another location like the outdoor probe. Now you have 2 remote location points per unit. I have also purchased a dc/dc converter to supply the 1.5 volts for these units so I don't have to do the battery thing and they can be powered by a switch or thru the onboard fuse box. Down side to this is the displays are large so as to be read across the room and I dont think they are backlit. What did I expect for poorboy style. I will take lots of pics and start (perhaps) another thread. I havent done a search on IC for this project, so sorry if I stepped on someones thread.
In contrast to the sub-optimal Insight design, IMO, the Prius battery pack has an elegant cooling configuration.
And, in contrast to the Arizona climate, the weather here in New England so far this year has been unseasonably cool. However, I did notice one day last week, that despite having the windows cracked, the interior temperature of the car was in the high 90's. The battery pack temperature showed only 71 degrees, suggesting effective thermal isolation.
Unfortunately, if it stays hot through the night, there isn't much that can be done to keep the batteries cool. Like Mike, I would recommend monitoring battery temperature, so at least you can know what's going on. My car has no A/C.
The themal mass characteristics of the Insight battery pack seem to enable a gradual increase in temperature, particularly with heavy use. As Mike mentioned, the fan isn't active during auto-stop or when the engine is turned off. Perhaps if you could force the fan on for about 5 or 10 minutes before solar radiational heating and heavy battery use it might help somewhat.
With regard to digital temperature indicators with remote sensors, I'm using an older Springfield model to monitor battery pack temp. The best feature of that unit is a temporary backlight that comes on for a few seconds at the touch of a button, enabling visibility at night.
Being a frugal yankee, I went for the $7 Oregon Scientific instrument for the engine air intake temperature monitoring, and I plan to replace it with a better one, as it's quite large, has no backlighting, and displays time and remote temperature alternately, which in this case is a nuisance.
The instrument I'd suggest is about $15 at Radio Shack, quite compact, with a dual simultaneous display of interior and remote temps.
The AAA batteries seem to last for years, and are easy to replace.
2001 5S, "Sputnik"; Various Modifications; 76.6 LMPG at 75K miles
I missed that one. That is exactly what I was going to try when I was finished withthe MIMA_C board testing. I asked Highwater to include the MPI temp monitoring in his test, so the best setpoint for MIMA to activate the fanscan be determined. Any additional fans needed (within reason)can be tied to the fan control power transistor in the MIMA circuit, using diodes to isolate the individual fans so the normal stock fan controlls will work if MIMA is turned off.
It turns out that the MIT electronics swap meet always has hundreds of those small fans available for cheap. I have a fair assortment in my fan drawer, but next month I will go there and buy up some nice ones that fit well in the ducts, and can include them with the MIMA kits.
Would still be great if we can get data on what temp the fans come on at, how quickly the battery temp can be brought down with the standard fan on high speed, and how much faster the pack cools with the booster fans.
Nemystic is all set up to also test the cooling characteristics, and may want to add some small fans on his car.
Since installing the battery temp. monitor, I haven't seen pack temperatures over 100 deg. F. Then again, here in New England, spring has been postponed. Today's high temperature is approximately 55 deg. F.
Next week, more of the same weather is predicted, so it looks as though we'll need to wait until summer to get more meaningful hot weather battery temp data from Sputnik.
Yesterday, while travelling well over 100 miles round trip, over nothing but large hills, the batteries had quite a workout. However, the pack temperature never exceeded 97 deg. F.
With compassion for the battery pack, and an unexpired IMA warranty, I've tried to limit assist to 50 amps, and regen to 30 amps. However, with the MIMA_L modification, it is possible to assist up to 100 amps, and to regen to 50 amps.
2001 5S, "Sputnik"; Various Modifications; 76.6 LMPG at 75K miles
I've been thinking of replacing the stock insight battery cooling fan with a pair of Vantec tornado's they are a little noisy but the car is a little noisy inside also and they move huge volumes of air, maybe someone could engineer a controller that controls their speed based on battery temps.
Also I've seen these window vents that are solar powered, you put them in the window and raise the glass to hold them in place while parked. The sun powers it, blows ambient outside air into the car. That should be the ticket. I would think.
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