Cold weather cruise control and unexpected engine ON

More than a hundred trials, never happened once to me.

 

I don't have a way to do video but here's what I did this morning.

Car in 48F garage all night, on charge.
Pre-condition using remote A/C for 5 minutes.
Back out of garage and start down the street, temperature outside 28F.
When I got off my block, I engaged cruise.
I used cruise to get to the highway, entered the highway via a steep uphill entrance to 65mph. Engaged cruise, see image below.
Drove on the highway until battery at 45%, then drove at 45mph with cruise until battery at 38%, all on cruise.
Charged from 38% to 77% outside.
Had car at dealer for maintenance for an hour.
Charge at 75%, temperature now 22F, drove to work which starts flat and then involves a slow climb followed by a flat followed by a major climb.
Got to work with battery at 7%.
Never tripped out of Ev.

 

Hmm...

 

First of all, great thread, thank you. I've also reported on instances where the ICE comes on mysteriously, for a short time while doing street driving (going 45mph or under, or stopped at a light), without any heat or A/C, with an almost full charge in the traction battery, and with the MFD showing the ICE is off when it's actually come on (ICE comes on when Stopped -- yet monitor shows it's OFF | PriusChat). The times I've noticed it have all been at night, but here in SoCal, I don't think it's been below 55F, and was not using the cruise control as it was city driving, stopping at signals).

Can't help with your experiment here unless the weather really dips. But one quick passing question... in the YouTube video above (time lapse) -- I always have my MFD set to that same screen -- in the video, above the battery icon is the percentage of charge left. However on mine, instead of, say, "83%" it shows the number of miles (17.2mi) left. Just curious, is there a toggle between the two? I don't think I've ever seen the percentage on that screen.

 

Page 233 of the owner's manual, last item:

 

Okay, I was finally able to replicate this:

1. Soak in garage all night at 55F.
2. Full charge.
3. Left for work, drove normally, mostly with cruise.
4. Got to work, all Ev, battery at 39%.
   
5. Plugged in at work, 20F.
6. Full charge and left for home after 5 hours at work.
7. Drove manually to the bottom of the hill near work, all Ev.
8. At the bottom, battery at 97%, car near zero power, set cruise.
9. Engine instantly came on at the press of the set switch.

I've done this many times before with the battery in the 70-85% range, no engine start.

 

so. if I'm reading this correctly, you want me to start the car like I usually do but instead of driving off on the trip you want me to immediately power down the car then put the car in ready mode again then drive off onto the trip that normally triggers ICE, right?

 

@priuscatprimeguy Today might be the last time this year you get to try this at temperature above 14f. Not that below 14f results wouldn't be informative too. I got snow too.

 

Very nice so far.

Question: Before when the ICE was coming on was it always after fully charging from a low SoC? Is it possible that the new full or higher Soc isn't being updated to the "code" the DRCC is reading on start up? Would explain why rebooting/refreshing fixes the problem. Wonder if there is a minimum SoC above depleted that still starts the ICE when setting DRCC?

 

no, not necessarily, I have driven round trip 5.2 miles to/from work and immediately charged my car and the next day went to work again and ICE kicked in