Is there anything I can do to keep Prius battery cooler?

I never thought of that. Sounds like a good idea. Did you install the tint yourself?

 

Wouldn't modifying the battery blower motor to run constantly simply lead to a potential of a whole lot of other problems?

I'm thinking you're obviously then asking the motor to run beyond the spec's for which it was designed. How long is it going to last with constant operation? And with constant operation...how quickly does it get clogged up and dirty?

Also just not enough tangible data to justify some of these conclusions. I'm not 100% sold on the degree of the problem based on- "A mechanic for Toyota told me that the 3rd generation is getting hotter because of a poorer setup for vents.".

Is that enough to want to modify the designed operation of a blower motor?

Contrast that against the really unknown amount of benefit someone may or may not get from doing it anyway. I can't say I'm in.

That being said, the most practical answer IMO is the recommendation for window tinting. You at least get the benefits of having window tint...regardless of how much that benefit may ultimately translate into extended Hybrid Battery Life.

 

I found a post with a link to the codes. At two years, it may not be the most up to date, but I do see fan speed control in line #103 of the linked Google spreadsheet:

ScanGaugeII work on 2010?

 

No. I had it done professionally by WTS (Whittier Tint Shop). It's guaranteed for life. Install the best. Well worth the $225.

 

I found Vincent's spreadsheet that expands Adrian Black's on line 103 that you found:


Set Battery Cooling Fan Speed 0 (Off) 07E230810600 02EA24700581 2701 000100010000 SF0
Set Battery Cooling Fan Speed 1 07E230810601 02EA24700581 2701 000100010000 SF1
Set Battery Cooling Fan Speed 2 07E230810602 02EA24700581 2701 000100010000 SF2
Set Battery Cooling Fan Speed 3 07E230810603 02EA24700581 2701 000100010000 SF3
Set Battery Cooling Fan Speed 4 07E230810604 02EA24700581 2701 000100010000 SF4
Set Battery Cooling Fan Speed 5 07E230810605 02EA24700581 2701 000100010000 SF5
Set Battery Cooling Fan Speed 6 (max.) 07E230810606 02EA24700581 2701 000100010000 SF6

 

Yea, I had similar concerns about running the blower motor continuously. The guy that posted the thread compared the price of a replacement battery blower motor versus the replacement of the battery. It was hard to argue his point.

The OP with his taxis would probably take a similar viewpoint. I would think he would rather replace a battery blower motor every once and a while if it extended the life of the battery.

 

I think the more relevant question is does the alleged shorter life result from the possible slight temperature increase or is it really the result of increased use. Pearl S uses the battery much more than Pearl ever did. Plain use will shorten the life much more than a few degrees of temperature difference. We're talking about a rather small capacity battery here (6.5 - 6.8 A-Hr) running quite high currents to propel the car.

I wonder if we could compare battery life in Canada with the US - particularly California and other "warm" states. That would probably tell us if the temperature is the prime contributor.

 

Does anyone know the default fan speed?

 

The fan speed changes base on battery temps. So there is not a default speed per se. The top speed is Fan Mode 6.

I have never seen the fan speed mode above 4 and that was at battery temps up to 120F.

 

Its probably a good location for much of the time but if you fill that area with bags on road trips (as we currently do), it could be a problem.

 

Ah. That's logical. The warmest I've ever my battery was in the low 90's. When it gets warm (weather) I'll have to moniter it on my ScanGauge. Thanks for the information.

 

JD, I have another ? about the fan speed setting: While the highest regulated fan speed is 6, and you change the mode... to say 5, will it stay at mode 5 without regulating it according to battery temperature?

 

I'm assuming the codes require a scan gauge. I'm rather unfamiliar with scan gauges, but would you have to input these codes every time you wanted to change the speed?

 

I have a 2011 Prius. My wife and I went on a trip and she put a light jacket on the back seat and it blocked the vent. After about 2 hours driving I smelled a terrible odor and discovered the vent was blocked. When I moved the jacket the odor immediately went away. I haven't had any problems with the battery so I guess it did no damage but it certainly was not good for it. It is very easy to block the vent.

 

Wow that sounds bad.

I wonder how hard it would be for Toyota to put in a sensor so it could tell if airflow is restricted and it would flash a warning light on the dash.

 

I think that the system has a fail-safe that will shut the car down to a limp mode if the battery temp. becomes critical. I could be wrong but it sort of stands to reason.

 

With a real ScanGauge-II, each speed would be programmed in as a separate X-gauge. Just scroll around to the speed code you want. Some of the other brands of engine monitors should be able to do the same or similar.

Imputing the full codes each time you want to change speeds would be an extreme PITA. If done while moving, it would (or should) violate state laws against texting.

Some folks here have reported terrible performance and MPG after being parked all day in the hot summer desert sun. A couple of them were able to get an improvement after driving part way home with the AC turned up, with the air intake source set to Fresh outside air instead of the default Recirculate. This strongly hinted that the engine management was minimizing the battery use due to the high temperature soak in the parking lot, and allowed it more function after enough cooled cabin air had been blown through it.

 

To follow up with what fuzzy1 said, you would have to configure an XGauge for the fan speed that you want. Then this XGauge would have to be one of the four displayed and active. As long as the XGauge is displayed and active it will override the automatic mode based on temperature and keep the fan speed constant.

If I were to set a speed on my car I would set it to probably a 2 and leave it there. I would not be wanting to change the speeds other than just to test. I have tested each of the speeds and monitored the BFM (Battery Fan Mode) and verified the speed change.

There are other devices such as Torque for Android and Engine Link for iPhone and iPad that can do the same as SGII.

 

I park my car in an open asphalt parking lot at work and during the dog days of summer my battery temps can be as high as 95-100F when I start it in the afternoons. I have tinted windows, use a Heat Shield on the front window and the best mod I have done is installed WeatherTech window visors so that I can crack the front windows open and this will cool the cabin temp a good 10F.

I start driving with the windows open to exhaust the hot cabin air while I have the AC on auto and set for 72. As soon as the cabin cools and the AC is blowing cold air I close the windows. The auto AC sets the vents to recirc as it helps cool the cabin down as quickly as possible.

Although this kills mpg for a while I have found that the faster you get the cabin cooled close to setpoint the sooner the AC compressor starts slowing back and the mpg begins to return to normal. Plus the faster you get the cabin cooled down the more you limit the battery rise in temperature.

I have about a 20 mile highway drive so by the time I get close to home the battery temps have stabilized and been cooled back down to about 93F which is where the battery fan turns off. By the time I drive the last 5 miles through stop and go traffic and get home the temp is usually in the 100-105F range with the fan running on a Mode 3.

If I park the car and then come back out an hour later say to go to dinner the temps can rise to the 115-120F range. This is why the guy that installed the printed circuit board to maintain fan running for 15 minutes after turning the car off.

 

What would you suggest doing with the air that you pulled out of the 12V area? Remember that these batteries are in the cabin area with you and the passengers. The reason that Toyota exhausts the air out of the car is for safety reasons. You do not want the battery exhaust air in the cabin with you.