As I've hinted at in another thread, I seem to have a problem with something in the HV battery cooling system. Today I got in the 'no-EV' mode after about 3/4 hour of city driving. The Tav temp (using my scangauge) was 91.6F. I had put 2 wireless thermometers in the intake and exhaust duct for the HV battery so I could monitor the temps of the air going into and out of the HV battery. I wanted to check and make sure the A/C was kicking in to cool the battery. It seems it was as the intake air temp dropped to about 45F. The battery didn't seem to be cooling much. After 15 minutes of cooling the battery hadn't dropped at all.
My question is how much air should the HV cooling fans be moving when they are running under these conditions? When I had the duct apart to put the wireless thermometers I checked and could feel the air going into and out of the HV battery, but it didn't seem to be a lot of air moving. Are the fans variable speed since when I did that check everything was cool. Would they be running faster when the battery is hot and the system calling for maximum cooling? If so I'll have to check next time I have things heated up. I can't tell much by listening as I'm quite hard of hearing and can't hear the fans running ever, although I'm sure they are.

 

Yes the fans are variable speed, they run faster depending on the speed you are traveling. They run very slow when stopped to keep noise at a minimum. I believe that they go full speed over 40mph. There are two fans in the battery each cools a bank of batteries. TAV is the average temperature of the two banks. If one fan has failed you may have one bank much hotter than the other causing the no-ev mode. You can set the scangauge to read both Tmax and Tmin (however mine will only read one at a time) to determine if this is the problem. Craig

 

It looks like I have a fan out (or going out). My Tmax is about 15 degrees hotter than my Tmin. As soon as Tmax gets to 100 F, no EV and it takes forever for it to cool down. I used a couple of wireless temp sensors to monitor the duct temps. I'm sure the HV battery A/C is OK because when the battery gets warm the temp of the air in the incoming duct to the HV battery gets nice and cold (40-50 F).
I found a link to a step-by-step to replace them, so I'm going to order the fan kit and give it a try. Wish me luck.

 

us035976, did the replacement myself, not a difficult task. Hardest part is trying to reuse the adhesive foam tape which cushions the connectors. Sticky stuff. Craig

 

Got this done today in about an hour. No problems what so ever. My fan kit came with new sticky foam tape, so no problem there. If you had to re-use it, I see your point.
I'll see tonight when I head out for dinner if it makes a difference.

 

Well, the cooling fans definitely were bad. Before I even got backed out of the driveway, I noticed my daughter was listening intently in the back seat. I asked her if she could hear the fans in the back. (I never could because I am hard of hearing.) She said yes and then said she didn't remember hearing them ever before.
In the first 10 minutes I saw my Tavg and Tmax temps dropping from the mid 90's to the mid 80's. I had NEVER seen them drop more than a couple of degrees in the past. After a half hour driving with a couple of short stops the Tmax temp was still down in the mid 80's. By then in the past it would have been up near or over 100 (and no EV mode available).

All is much happier in FEH land.

Thanks CraigS for the tip about the Tmax and Tmin xgauges. That helped verify that it was the fans that were bad.