In cold temps, ICE turns on at the begining of a trip when I have plenty EV. Why?

Rob, that is my observation as well. If I drive in golf cart mode for a mile or so, the ICE will not fire up as readily.

 

pfft, I walked a mile outside yesterday, and it was colder than that
(Temps yesterday supposedly were 14 to 23F in Clawson, and -8 to 16F here)

 

My conclusion under the circumstances I generally see during the winter at my location (20F to mid 30'sF) is that the ICE starts to protect the battery from over charge from regen braking based on the potential energy available depending on vehicle speed.
It seems that under 22mph doesn't have enough potential energy to over charge an almost full cold battery where 35mph (random number) regen braking has enough potential to possibly over charge a cold almost full battery.

If T could give us the option to turn off regen braking- we could keep the ICE from firing up at these low temps.

 

started my day at 20 degrees car out side all night, recharged early evening, drove to the gym at 8:30 had 9.6 on the ev est. drove as slow as i could. 2.5 miles on 35 mph streets 3 miles on 50 mph hyway. on way home made one stop. Got to 9.9 miles ran out of EV HV the last mile home, was nice to have some heat for last 1/2 mile.

 

My coworker who has a Rav4EV said he got that message on the dash this morning (high 30s?). He said it read something like "Regeneration currently not available" or something to that effect.

So its definitely something "T" knows.. although T is this case could be Toyota or it could be Tesla.

 

Throwing it in Neutral will prevent regen.

 

The key is to drive however you want when no one is behind you, and then not slow down the traffic when it's there. Of course, I don't make any effort to accommodate those who want to go 10+MPH over the limit...

 

Thanks! ny_rob! I'll try that out.

 

and....where is "here?"

 

A interesting Prius Plug In experience today. I had some local running around to do. Left the house with a full charge, 9.8 EV. I was in HV until my return home. Four stops, with 7.6 EV remaining, I returned home. As I was close to home, I didn't think I'd make it in EV. I was at .1 EV when I turned into my driveway. Great, I made it. As I turned to pull into the garage, the ICE cut on. &%#$@!, or something to that effect. When I shut it off, (maybe 30 seconds) the display indicated 10.5 miles traveled in 20 minutes and mileage was .999. That's a first. Getting full EV credit with the ICE cutting on prior to shutting off the engine. Also, on my return trip, the display indicated 7.6 miles EV available and I traveled 10.5 (very little regen), temperature in the low 30s. Total trip was 22 miles. Smart car, dumb driver?

 

...and I've used it successfully to stop ICE start due to brake regen when approaching a traffic signal. Unfortunately, it's not practical to drive when in "N" rather than using "N" when coming to a stop.

 

Agreed. Just another tool in the arsenal.

 

The mystery continues. Car was parked outside overnight with lows near 10F. Battery charged to finish at 8am. Drove to work this morning with no ICE...

 

Maybe the batt was still warm from charging?
I'll have to give that theory a try...

 

Oddly I've tried this in the past and it hasn't worked.

 

Yep! like I say it's got a mind of it's own!

 

I do think I also tried that last winter- without success.
But I'll try it again just for $hits and giggles...

I also tell ppl the Prius has a mind of it's own, and it's very difficult to make it do something against what it's hardwired to do.

 

even though the parameters me seem the same to us when we think the ice fires or doesn't under seemingly the same conditions, we are not able to sense and computre everything the car is doing.

 

I am really dumb when it comes to this stuff!
Is it possible it'is not the cold at all per say but is just so many amp draw or the same in reverse for regen. braking, setting off sensor? Causing ice start up.

 

you could be right. temp affects other things and they probably measure the symptoms instead of the cause.