ICE running more in hot weather

Does the C have a HV battery vent in the rear seat? If so, is anyone blocking it when sitting there or has a jacket been throw over it by mistake?

 

One possibility is that the traction battery might be getting too hot, and is going into a self protection mode. Check out this thread, where some actions aimed at this possibility (e.g. use more AC, and put in into fresh air mode instead of recirculate) did help: ICE Runs for 20+ miles in HOT Weather

 

We just had some big temps here. The C, in my experience, doesn't like big degrees. Sounds about right to me. When your temperature goes down again make another evaluation. Maybe take a ride in theses hours when it's cooler. Below 95 degrees seems good.

 

I almost NEVER use automatic climate control on my 2nd gen Prius. I don't know what it's going to do and when (with respect to AC compressor, what air is being blended, etc.) Most of the time, I want control.

If the AC compressor is on, then the drain is a lot greater than when it's not, when idling. I don't have numbers for the c, but on my Gen 2, w/no headlights on, I see a drain from the HV battery (which is ~220+ volts on the Gen 2 Prius) of ~1.2-1.4 amps w/AC off. If I turn it on and have the HVAC fan on high, the drain can be as high as 11.x amps.

If you're running down the HV battery, the ICE must turn on to help it charge back up. And, if that auto setting results in the AC compressor turning on....

 

The a/c really sucks the life out of this car. Even judicial use can make the engine run to keep the battery up.

In the C, I usually have the temp at 75 degrees. If it's close to that I'll just turn everything off and maybe roll the windows down. If it's in the 80's I may turn on the A/C. If it's in the 90's it depends on how I feel. I smoke cigars, so I keep the window cracked, the recirc off, and the fan on feet blower. Comfort is good sometimes, circulation is good others. Where ever you wish to draw the line is fine. Sometimes you can splurge and turn on the A/C. The world world will not end.

 

The battery capacity on the Prius c is smaller than that of the regular Prius (aka liftback), so it wouldn't surprise me if the ICE needing to run more just to keep the HV battery's charge sufficient, esp. w/AC on.

 

The C's fan is very quiet, I can't hear it when it is running. It may even be a variable speed fan. I can very definitely hear the fan on my Gen 2 though.

I have noticed the C's fan running at a low volume when the weather is warm. Here in the south it has been 100F+ for many days in a row lately. I can stick my left arm back between the door and A Pillar and feel if the fan is on at the battery air intake.

My experience is the C runs pretty efficiently if you have ECO on, AC on, and the fan speed set to low or one up from low with temp set to 74-75. When it is 80 to 90 outside I can still hit 60 mpg on my commute home over hill and dale here in NC.

BUT, when it was 106-107 recently here, AC set to 74-75, my mpg really took a hit with AC in AUTO.