This is my first year driving my prius during a hot season, and for past 3 weeks my mpg has dropped from 49 to 41-43 mpg, and the reason is my traction battery keeps getting HOT! I can hear the battery cooling fan turning on constantly at max when i reach 20 mph, my car doesn't want to start in EV mode the engine just kicks in no matter how light you press the throttle, the EV motor is not assisting with the engine, the infamous slow rpm drop keep occurring and I when to touch the traction battery case and it its HOT, Ive open up the case to check for any dust on the fan and ducts but so far its spotless. I really wished they place an AC vent for the battery because the back passenger area with full A/C doesn't t get as cold as the front dose which doesn't help cool off the battery.
Your location and ambient temperatures would help. Do you have any way to monitor battery temps; mini-VCI, ScanGauge, Torque, Engine Link ?
The only obd2 gauge I have is ultra gauge however I doesn't measure battery temperature, u could install a surface temperature probe that I have, or get an scangauge,by the way do they sell an obd splitter?
First, where do you live and what are your high ambient temps ? They do sell OBD splitter cables. I do not believe UltraGauge has XGauge capability. The ScanGauge does. All of the XGauge parameter settings can be found on here, including all of battery parameters. The ScanGauge can do everything the UltraGauge does plus XGauge. You would not need both. You really need to monitor the internal battery temp sensors. The outside case temp could give you some idea but not the internal temps. From what I understand the computers begin limiting battery output at 116F.
I live in Oklahoma and we get both ends of the spectrum of either extreme heat and extreme cold and it changes rapidly, like yesterday we were averaging 98*F with 80% humidity, you may not think 98*F is hot but when you factor in humidity it's feels like your in a wet steaming sauna that no amount of a/c will cool you off and for the last week it's almost the same hot and sticky, but today temp is cloudy wet and 75*f for highs! And my average is now 47 mpg! So it's clear that my traction battery is overheating due to environmental factor, but how much is too much for the battery?
JD Collins has cited 116 Fahrenheit, which converts to 46 centigrade. Seems to me I saw mid-forty's one time, when starting up and driving after a previous long drive, followed by parking in hot sun. Perfect storm I guess. Parking in garage after a long drive in hot weather, maybe that's another bad scenario? Slow cooking?
Humidity has no effect on the battery, only on humans. Temperature is temperature. You're sure the battery vent ducts are clean? Is the exhaust flap stuck shut? Oh, and it doesn't get "really cold" in OK. Unless you regularly see -40.
I checked then both they were clear from any obstruction, humidity has not affect on battery but it has an effect on a/c efficiency and performance which means that it has to run longer and harder to keep it cool. I have my ac full blast all the time to try to cool the cabin, however the front of the cabin gets cold by the time it reaches to the rear compartment it's Luke warm
I would complaint to have a hotter Hybrid Battery overheated in your climate, what do you expect????, as Bisco said, run you A/C at full blast to keep everything inside the vehicle at a comfortable temperature and mean while....lowering your MPGs. You are in Oklahoma for goodness sake.
In the few experiments I've done, maybe not conclusive but anyway: running AC only put a minor dent in battery temps, dropping the battery's middle sensor (supposedly the hottest) by only one or two degrees centigrade, over the course of at least 1/2 hour driving. That was with temperature set for comfortable, not ice cold. And it seems to me if one of the prerequisites for battery survival is driving with the AC running full tilt, the engineers have dropped the ball.
No sure what your trying to say...Even if I leave my car on a hot day after sitting overnight it still acts the same way. And using a/c won't affect it that much in mpg.
if your a/c is lukewarm in the back seat, i would have it checked out, maybe you need a recharge. mine is freezing, i can't run it full tilt all the time, but we don't have your heat.
What makes that clear ? Did you measure battery temperatures ? As for how to handle high humidity weather, manually set the ventilation to high(er). The temperature setting can be something more reasonable like 77 - 82F
If its hot for me, its hot for the battery, so I run the AC most of the summer. Yesterday AM it was overcast & in the lower 80s so I had the windows down & no AC. First thing (early) I had filled up with fuel & with no AC I was getting >60 mpg on the display. When I stopped at McDs for tea I was up to 65.7 on the display. When I left it had started to get really hot/humid out - ~91-92°, but I had this great mileage going so I went with the windows down for a while. I was driving in town & about 30-45mph with some traffic lights. I was OK with the windows down but suddenly thought about the battery. I keep my BT adapter plugged in so I just fired up Torque on my phone & looked at the batt temps & fan speed. The middle batt temp sensor was at 114.x & the fan speed was at 4 - the battery was somewhat warm but the vehicle was still performing great. This was the first time I had ever seen the fan speed at 4, although I still couldn't hear it. I was up to 66.2 mpg by then (still with windows down) & had >100 miles on the tank. I closed the windows & fired up the AC. It only took ~5 minutes & the inside was cooling down nicely. It was still 91° outside. I monitored the batt temp & in 20 minutes the center temp was down to 109.x° & the fan speed was down to 3. Perhaps when it is really hot you could let the AC cool off the cabin for a few minutes before moving? Once the vehicle gets really hot it will take some time for the large mass battery to cool off, even with good air flow. I've got the pass. air vent (adjacent to the window) blowing straight back - actually all the air vents blow straight back. On the positive side it is good to see the Prius is protecting its battery as best it can under these conditions.
I have the similar high 90's and high humidity living on the coast of NC. I have seen my battery temps in the 110-120F range especially with city start/stop driving. Once again, you really need to get something to measure your battery temps so you can know whether this is normal or not.
I see lots of temp numbers being thrown around. What is the normal operating temperature range for the traction battery? I have not seen any published numbers.
What was the temperature outside at the time? What was the temperature inside with the A/c off? With Vancouver's mild climate, the chances are that the a/c wasn't working very hard anyway and perhaps the battery fan wasn't either. If so then you would not expect much difference in temperature.
