And I watched my traction bat temp all the time. I was frustrated at finding some guideline as to where the "safe" temp for longevity. I still don't know other than cooler is better and I trust the Toytota Engineers, who don't say schit about "safe." On the trip I found the highest temp at 93 degrees. Ugh, simply because that sounds high. Ambient outside was 82. Inside was 86. (It wasn't THAT high by simple comfort...I don't know where the inside sensor is.) So after fidadling around with the AC and turning it on, then off, then remembering to switch it to "outside air" duh....it came down to 82 degrees. It really need positive cabin air pressure to force air through the rear seat air vents. That was the biggest change. My conclusions...... Either DONT install the Scan guage.... Or don't install the code for traction bat temp... Or don't worry about it ... Or drive yourself crazy like I do worrying about high temps....93 seems high...dunno if it is. Any other thoughts? Why doens't Toyota give any guidelines?
unless you are in a very warm climate, i wouldn't worry about it. and even then, warranty gets you average lifespan.
When trying out one of the pre-production Volts before they came out, I asked one of their engineers about battery temps and he summed it by saying, "if you're comfortable, it's comfortable". IOW, don't sweat those readings (pun very much intended). On another note about data: I had a motorcycle that used a traditional dial gauge for the coolant. It typically sat at about 40% on the scale (no numbers just the terms "Lo" and "Hi") and barely budged from that spot. The next generation of the model went to a digital readout and soon there were TONS of overheating concerns on the forums. The new owners (many of whom were previous model owners) were shocked at how high the temps rose on the new bike and how much they varied as opposed to the old "cool running" bike. I bought a wrecked unit of that previous version, repaired it and did tons of mods to it (current avatar) including adding a new, advanced instrument panel which had a digital coolant display. Yes, it reported the same "high temps" and variances that the new model was showing.
Quote... unless you are in a very warm climate, i wouldn't worry about it. and even then, warranty gets you average lifespan Yep...wish I could think that way...I can't. Hahaha...exactly. I really don't wanna just ignore what we think as normal...and the attitude of "just drive it." I'm not trying to insult you, I'm trying to suggest I can't just accept how "they" suggest it. Doesn't anyone know if 93 is too much? I read one web page that says 86 is the tops we should see. And when I turned on the air, not the AC, and then remembered to turn it to outside air instead of recirculate ... that is when it went down. Priuse kitty...the code I don't remember...but it's on here somewhere,..that;s where I got it.
93F is actually pretty good for the HV battery temp. The HV battery fan does not come on until temps reach 97F and then tries to maintain temps between 95-105F. I have seen it as high as 115F in NC with 95F temps and a lot of heavy stop/start driving. Search on here for HV Battery Fan. TimBender (?) has a good thread going on this very subject.
Good information JD, that's what I wanted to hear about. I guess if the Toyota engineers turn the fan on as high as that then perhaps I should "attempt" to not worry about them. I looked for that thread you suggested ... never did find it. And the search doesn't turn up a TimBender. Thanks for the information.
I dont think 93 is high. I've logged my battery temps a few times and as I recall, the lowest I've seen it is around mid 80s (in the morning) and mid 90s in the afternoon. I recently tried logging again since it was pretty hot in the afternoon on my way home from work. Here's the hottest I've ever seen the battery. The X-axis is the "time" (minutes.. it should've started at 5:54PM and ended at 6:29PM if you look at the numbers). At about 6:20PM is when I start my "climb" on a stretch of road where I need to maintain 55MPH+. I probably ran out of EV range around the 6:25PM mark. And, lastly, I dont know where each temp sensor is located. I just know there are these 3 so I log all 3.
Excellent graph. I see the max temp was almost 108 degrees. Which would shoot my eyeballs out of my head....lol. Here's the problem as I see it. No one seems to know the dangerous, for longevity, temps. JD says Toyota turns on the fan at 97 so if Toyota deems it worth some cooling at 97+ then that's good enough for me. On the other hand, I've read that the lower the temp the longer the li-ions last. It's sad that Toyota doesn't give better guidelines ... I assume it simply comes down to liability.
You don't wait until a patient dies to administer treatment. The fan comes on above 35C and then there are varying levels of fan speeds. Since it is just exchanging the hotter air with other air. If you want to be worried all the time, then pulling C's out of a cold battery is also bad. The "if you are happy, the battery is happy" remark is spot on for Lithium and NiMH. Happy is best, deviation from that is bad. You will survive at 40C, so will the battery.
Warranty generally gives you minimum expected average lifespan. The "left side" of the distribution right before the bell shape appears.
There is an active fan that will cool the battery if it gets hot. You can monitor the temp and fan speed and make out the upper limit temp. The bottom line, there is nothing to worry about. The BMS will take care of it as programmed.
See this thread Traction battery fan | PriusChat. His name is Tim Bender with a space in between. I left off the space.
Thanks...I just read it. I couldn't understand how I missed it then I noticed that it's in the Gen lll forum. I wonder if a lot of the research/info would also apply to our PiPs?
I would think that the PiP battery fan would be very similar to the Liftbacks but someone with the PiP would have to verify.
I don't know the exact algorithm of how the fans are controlled but per the SAE paper, the PHV model has an upgraded cooling system (2 fans instead of 1?). I would think the speed of the fan will correlate with the temp of the battery pack. The air is drawn from the cabin so if the driver is comfortable, so is the PHV battery. The Lithium cells are kept in a constant pressure structure and they are monitored by a unit designed by Denso.
