Some Insider Notes on the 2017 Prius Prime - Part 2

I was a little confused about the difference between HV, EV, and EV Auto modes, even after having my Prime for a few days now. I was primarily driving around in EV mode (shorter trips in-town), going to HV mode yesterday for a highway trip 30m outside of town. Main reason for the confusion was that even with EV mode on, the ICE was kicking on at times, even though there was at least 15 miles of EV range still reported. This was sometimes happening even when I wasn't going up a hill, so it was confusing.

After some reading on here, I found that the ICE *will* kick on at other times. I think that at least a few of the times were related to the climate system (heat) being on, even in "Eco" mode. I turned it off and the ICE activation seemed to become much less frequent, but still was occasionally kicking on. Why? Probably because the air temperature in the last couple of days has been below 20F, sometimes below zero.

I report this only so that other cold-weather Prime owners who are puzzled by the ICE activation in EV mode realize that it might be a function of it being bloody cold. Hopefully ICE activation stays at a minimum in somewhat warmer conditions...

Side note: very impressed with the brightness and coverage of the quad-lamp LED headlights. Even more impressed with the brights, which are fantastic on rural highways/roads...and the auto-sensing mode worked beautifully. Not all that useful in cities, but when I do venture into rural areas after dusk, it'll be much enjoyed. Didn't expect the headlights to impress me so much!

 

Turn the heat on when the temp is below 14F and the ICE will run.

 

Prime EV Auto is what the old Prius calls EV, allowing the ICE to start on momentary Power use.
The Prime EV Mode (not EV Auto) will NOT start the ICE when you step on the accelerator. ICE will start if over 84 mph or no battery.

 

It can still start the ICE in Ev mode with heavy power demand. I think it only does this in certain circumstances such as low SOC or off-nominal battery temperatures. In my case, it did it when I had less than 2 miles of Ev mode left and I brought the accelerator almost to the floor on a test drive. The engine stopped the instant I let off the accelerator and the mode remained Ev for the entire time.

 

Now that's interesting that in EV Mode (not Auto) after the ICE started, it STOPPED when you let off the accelerator.
Had the ICE been running before and was Warmed up, OR was it COLD and stopped, unlike the old Prius?

 

It was already warm.

 

Electrec did a Prius prime review in Feb. The reviewer was beside himself over the frequency of the Prime's ICE coming on in EV mode. It was winter and he was in a cold climate.
I am too new to the forum to be allowed to post the link. Just Google search: " electrec review 2017 Prius prime not the EV you're looking for " if you want to check it out.

 

I haven't been able to make the ICE turn on in my Prime in Ev mode without running out of charge or pushing the HV button. I've done 0-60 runs, floored the pedal when it was below freezing, nothing. The time it did it when I was test driving was an exceptional case - warmed up engine, almost no Ev mode range, floored pedal. That's unusual because you usually don't have a warm engine in Ev mode.

 

Every time I try to defrost the front windshield, the engine comes on. I only have to do this in cold or cool, damp weather.

Bob Wilson

 

The heat pump can cool or heat, but not both. For defrosting you want the cool function to remove the moisture from the air. But that will also cool the air, to heat the cooled and dehumidified air you need the heat from the engine. Maybe this is the reason why the the engine comes on in this situation.

 

heated windshield solves the problem.

 

Not really. I can't remember a time where the inside window fog was so severe that I needed the defroster and yet only needed it on the front window. Every time I need it on the side windows too so I can see left and right and through my mirrors.

A simple solution on the Prime is to turn on the regular heat just directed at the defrost vents. This really seems to work. If you need moisture pushed out you can just crack the rear windows.

 

More of a Faraday cage <grins>. It would also inhibit cell phone operation from the cabin.

Personally I would prefer to see the GPS receiver as part of the rear view mirror mount or incorporated in the shark fin.

Bob Wilson

 

how could anything ruin toyota gps?

 

Isn't the GPS receiver in the shark fin?

 

so the heated windshield is back on the table again?

 

Maybe the Prime heater controls differ fron the Euro version, but on mine the only setting I can see to direct air to the demist vents is the demist setting itself. Am I missing something?

Posted via the PriusChat mobile app.

 

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