58.4 C (137 F) Temp on HV Battery per Torque Pro

Can anyone beat that for an HV battery temperature?

This is the first time I've driven the Prius in the desert in near summer-time temperatures. The air temp was in the high 90s when we left North Las Vegas late this morning, headed for cooler temperatures in the Mount Charleston area. The HV battery SOC was at 1 purple bar for most of the way up the mountain, with air temperatures having dropped to the high 70s as we made our way there. When we decided to stop at the Spring Mountains Visitor Gateway for an hour or so, I let the car idle for a few minutes, which brought the SOC up to 3 bars. We then continued up to Kyle Canyon over an undulating stretch of road, over which the SOC ranged from 2 to 4 bars. When we stopped for a few minutes at the lodge, I remained in the car with the AC running in Ready mode, since my mother-in-law didn't want to get out with the rest of the family. We then drove back toward the Visitor Center, but this time took the Deer Creek fork that leads to the summit, a further climb of a couple of thousand feet. By this time I was feeling a little more confident in the car's ability to handle these types of conditions, despite not having stressed it in quite this way before. (I should mention that I was struggling to keep up with my nephew the whole way, who was driving a Dodge Durango with a Hemi engine. I have only owned this car for about a year, it has been spent most of its time on the West Coast, but has now crossed the country twice and made 3 round trips between New York and Florida. Crossing the Continental Divide on 2 occasions was the closest it had ever come to what it had to endure this morning, but the air temperature was 20 or 30 degrees lower then.) My mother-in-law again remained in the car for the hour or so that we were walking around the viewpoint, but rather than letting the car idle, this time I opened the hatch and a rear window. There was a fairly stiff breeze, and the air temp was only in the 70s, so I was not worried that the temperature inside the car would become uncomfortable.

When I returned to the car and put it in Ready mode, I could immediately hear the battery fan come to life, an occurrence I had read about on this forum, but had never experienced before. I then connected my ELM327 device and started up Torque Pro and was astounded to see the Fan Speed at Level 6 and the center battery sensor at 58.4 C. The other sensors were both about 54 C. I remember being concerned that the battery had suffered permanent damage last summer when I saw a Fan Speed of 3 or 4 and battery temperatures around 44 C on one occasion driving around NYC on a day the temps were in the high 90s. I did not have the luxury of letting the car idle to hopefully cool down the battery before we started down the mountain, as once again I had family in the car and my nephew was expecting us to stay close behind him. I was trying to keep my eyes on the road while glancing at the Torque Pro gauges as we descended. (It didn't help that my wife was accusing me of texting while driving. If I tried to explain to her that a hybrid car has these unique requirements, I'm sure she would just say "Well, why don't you just get rid of the car then and never buy another hybrid?".) I had the shifter in "B" mode most of the way down, and saw the battery temps slowly drop into the mid 40s C and the Fan Speed to Level 4. The SOC slowly rose to 7 bars, but never went to 8. We stopped for lunch once we got back into town and when I got back into the car I saw that the battery temps were now in the low 40s C and the Fan Speed at 2. We spent some more time driving around town and the car has not seemed to be doing anything unusual. I'm hoping to get the car back to New York in a couple of weeks, but in the meantime will be doing quite a bit more driving, mostly in the Pacific Northwest. I'm wondering if today's events might have put those plans in serious jeopardy.

 

I didn't even think about the effect it was having on the transfer case. Yes, the engine was screaming both going up and coming down, and with 237K miles on it, I did consider the possibility that it might throw a rod or something, but I guess we Prius owners tend to obsess over battery health more than anything else. I'm just curious why I didn't notice any fan noise after the first stop, when I had done most of the climbing. It seems there was a couple of hours delay between the discharging of the battery and its overheating.

I did change all the fluids right after I got the car, so at least they should have had some life before I found myself stuck in this situation. I will change them again soon, but I will probably try to make it back to the Pacific NW where I have a yard in which to do the work.

 

In a way, I'm glad I did have it on re-circ. Smelling something burning would have been as stressful for me as it would have been for the car. I believe I'll second your opinion about the G2 being one of the toughest little cars ever. I've been driving it today and it seems none the worse for wear, but no more trying to keep up to V8s.

 

I'm guessing the engine coolant temp was probably Ok, since I didn't have any warning lights come on. I do have a gauge for that on one of my Torque screens, but I wasn't focusing on it, given the issue I was having with the battery temp. My thoughts on that are that it was caused solely by heat soak, after stressing the battery by discharging it and continuing to run the car for an extended period in that condition. I did clean the HV fan shortly after I bought the car about a year ago. It was not in bad condition at all, when I opened it up. There was a light coating of dust, which I was able to remove fairly easily with moistened Q-tips, no pet hair or anything like that. I will change the trans fluid and inverter coolant as Ed suggested, but apart from that, just take my time going up any long hills from now on.

Posted via the PriusChat mobile app.

 

Thanks for the advice. I wasn't aware there was a flap that needs to open. Unfortunately, I don't think I'll be able to open the HV cooling vents again until I leave Las Vegas as I don't have any tools or place to work here. Actually, I'm pretty sure the fan is doing its job, since the temperature did start to come down after I got back in it and began driving it. I never heard the fan at all driving up the mountain. I believe if I had left it in "Ready" mode after I reached the top, instead of shutting it down for an hour or so, I wouldn't have had the problem, as the fan would have helped to dissipate the heat that was coming off the battery. I'll be very careful driving back to the Coast over the Sierra Nevada in the next day or so. I will keep an eye on the battery temp with my Torque app and pull over while keeping the car in "Ready" mode, if it starts to get too high.

 

Well, the car did survive the torture test I put it through the other day, but I can't believe it has not suffered some ill effect, however minor. In particular, we know that excess heat will shorten the battery's life, and that is the main thing that concerned me. I was not really intending to force-charge the battery half-way up the hill, as Ed had suggested. I recall reading an opinion on this forum that revving the motor in "D" while holding down the brake would actually increase the temperature of the oil in the transfer case, which would be really counter-productive. I believe letting it sit in the "Ready" mode for a few minutes half-way up the hill to give the fan a chance to dissipate some of the heat that has built up as the battery discharged cannot do any harm.

 

>You can override the fan control using a ScanGauge. You might check to see if you can do it with your reader. Set it on high and see if it helps.

I wasn't aware that I could control any of the car's functions. Knowing that I could override the fan control with ScanGauge is useful information, and if I ever reach the point where I feel the car is not managing its systems correctly, I will look into getting a ScanGauge. (I'm assuming that the TorquePro app that I have come to rely upon for monitoring the car's systems does not offer this functionality, but if anyone reading this knows differently, please let me know.) We are now out of the desert heat, and the car did not seem to be doing anything unusual going over the mountains on its way back to the Coast or since then on the drive back to Washington state.

>Is your battery original? Also, does your Prius consume oil like other high mileage Prii?

I'm pretty sure the battery is original. When I opened up the back panels to check the condition of the fan after I bought the car, there was no evidence that any any of them had ever been removed before. (All the plastic clips seemed to be where they should have been and none of them were bent, which is not quite true anymore, after I was done with them.) I didn't respond to the survey asking whether the car had been garaged, etc., because I'm not really sure, as I am the 3rd owner and I bought the car with 211K miles on the odometer. I would guess it hasn't spent a lot of time in the sun, because the paint is still in very good condition. Based on the few maintenance records available, it seems to have spent its entire life in cool San Diego and then Vancouver, BC, before I bought it and took it to the hot and humid East Coast. It consumes relatively little oil for a car with now 240K miles on the original engine, perhaps a quart every 3,000 miles.

>The newer Prii don't use the battery near as much on hill climbing like the 2nd generation, where my 2005 would suck down the battery on a mountain pass, my 2012 v wagon won't even hardly use the battery, usually charging on the way up. Less battery cycling so that's probably good. Just a interesting observation of mine.

I was not really expecting this car to last very long, with the number of miles on it when I bought it. I guess I really viewed it as a trial purchase to see how well I liked driving a hybrid, before I spent money buying a new car. It's good news that the new model uses the battery less than the old, yet still gets even better mileage, but I was already convinced that the Prius is the new car I want, anyway. Now it's just a question of how long the old one hangs on to life. I'll gladly move on when that happens, the old car having more than paid its debt to society.

 

No one ever came back to me saying the fan speed could be controlled with Torque Pro, so I think it's safe to assume that you will need another device such as ScanGuage to do that. I would hope that for $160 it can do more than that. I know a lot of people swear by them, so it might be worth the investment.