Prius Prime: detail about Charge-Mode

Yes, it does. When you open the car door, the heater cuts off. Then I go and unplug the car. My battery is 100%.

 

Interesting. If I set the Prime to be ready to go at 5:00 am it's always ready to go at 5:00 am. If I set it to precondition and be ready at 5:00 am it's never ready at 5:00 am. I go out at 5:15 and it's still charging.

 

I leave mine plugged in all the time on the 8 A with no program.

 

Preconditioning and Remote A/C always uses the battery and the last climate control setting. If you have the climate control set for 80 degrees and it’s 40 out, the Prime will heat the car with the heat pump. If the car is plugged in when this happens it will attempt to provide the battery the electricity being used. When I set mine to Max Heat even my L2 cannot keep up for 10 minutes and requires an additional 10 minutes to replace what was used. I use preconditioning all the time during winter, but just before I leave I also use my Remote Climate app to set to Max Heat, but I don’t allow it to run the full 10 minutes. After preconditioning it only takes about 3 to 4 minutes to jack the temperature to toasty.

Another use that might actually be recommended for the Charge Mode, is if you are on the highway and weather may move in that could bring traffic to a halt, like a blizzard/snow storm. It would be wise to use Charge Mode to fill up the battery (tops off at 80%) and then if traffic comes to a halt you have a hot heater core and enough battery to provide heat for hours. All without worrying about carbon monoxide poisoning or snow blocking the tailpipe. Might have to turn off lights and other non-essential things but it will make the wait that much more comfortable.


iPad ? Pro

 

Depending on the conditions present the sensors detect - I've not always been able to start PreConditioning...

The systems are setup pretty well, calculating and adjusting to driver presets when necessary.
Unlike us, the car does not always make adjustments to it's historical data computations and present sensor computations, instantaneously. I think that is the reason so many of us get confused by what we see / read from the Primes gauge readouts.

In sub freezing weather I can always get preconditioning to work, but I manually heat the cabin with a space heater both while charging and before leaving (if on the rare occasion those two times are different).
I'll still run the preconditioning (if I remember and or have the time) in the hope that preconditioning also heats some of the vital electrical components under the hood. (like a block heater would normally work).
I have no clue if preconditioning actually does heat any of those items, but if it does I want them warmed up before I leave. Due to I'm always loosing heat in EV mode as I drive and I've found that in EV mode the car struggles in rain cold and snow for lots of reasons. Anything I can do that Toyota offered to help make those times more efficient I'm going to try to use to the best of my abilities.

I noticed with the PiP I could run in EV mode below the minimum Temps Toyota said the ICE would fire up, by using creep home mode at the beginning of the trip. It took about a mile of creep home mode speeds before I was able to start driving at 20 mph for another mile or so to finish the (what worked in my case) EV warmup mode in temps well below 20 degrees F.

 

That is an issue with L1 charging. And it doesn't make sense since the A/C doesn't really draw all that much. With L2 I haven't noticed it.

 

I set pre-conditioning while plugged into the L2 chargepoint charger at work, and it was still charging when I got to my car 10 minutes after the departure time I set.

 

Hmmm. If you're trying to warm it from say, 0F to 70F, that would take a lot more power than to cool it from something like 105F to 70F. Maybe that's the reason? I have sometimes noticed that mine is still charging when I'm ready to go when I was pre-conditioning the cabin in hot weather. But it was so nearly done that the SOC still said 100%. My conditions are very different from yours.

Clearly to me, the system is not perfect. But it's still better than nothing most of the time.

 

When plugged in at 120 volts, even when charge has finished and preconditioning is run, when preconditioning is finished I've always seen my Prime need ( up to 30 minutes ) more charging time to top off the traction pack again. And besides that, sometimes the GOM will take a few tenths of a mile hit on the available EV range compared to what the GOM showed before preconditioning was run.

I don't care about those issues, I still use it. When I know how to manually do everything the precondition function does I may decide to manually precondition ( if possible ), but only if I can do it without missing anything the car does automatically.

Till than I just push the button and prey it's not a complete waste of time and energy, which I still believe it is not.
I already take care of heating manually, which also uses more energy on top of what the car normally uses.

Just a hint about what systems are being started and used during the precondition cycle if that's important to anyone else.

 

Mine is only 2 weeks old so I'm still in learning mode.

 

I suspect the code that calculates when to start charging does not take preconditioning into account. It seems that the car just hopes you're on L2 so it can "brute force" the situation by finishing the charge while also powering the climate controls.

If the system were "smart" it would notice the call for preconditioning and know it has to start charging earlier than usual, depending on differential between outside temp and pre-set climate controls. Then it would charge to 100% before firing up the climate controls, which should then run purely from the A/C cord. But alas, it doesn't work that way.

 

When I used pre-conditioning on a chargepoint station recently, it finished charging some time (maybe 30 minutes) before my departure time. Them it started pre-conditioning at the right time, but didn't start drawing power from the charger again until the pre-conditioning was almost or completely done. When I got in 10 minutes after my departure time, the heat from pre-conditioning had dissipated, and it said 20 minutes to fully charged. Seems like a waste in that case.

It seems like maybe it only uses the battery no matter what kind of charger you use.

The traction battery cooler cycle also heavily uses the battery. It runs for 30 minutes, but in that time the battery only gains about 4% charge on a L2 charger. The chargepoint graph shows it not using any power at all from the charger for much of the cycle. But I guess it gets enough charge at the beginning and end to still have a small net increase in charge.

 

I've only seen this once, and it has nothing to do with charge mode or preconditioning except by default if you want to add it to the variables of what all the preconditioning functions are. I plugged in at 120 volts with temps well below freezing ( 32F or 0C ) and no lights came on for about 5 minutes. No green light at the plug/socket, no blue lights on the dash and no graphics on the MID indicating charging.
After checking all that stuff, I figured the traction pack heaters were warming the pack.

edit: I didn't have the space heater running inside the car either. One of the few times during the winter I didn't use it while charging at home.

 

Yeah, I suspect the same.

That would explain a lot!

 

I'm not willing to make assumptions about what it does and doesn't do yet.

Don't get me wrong, I've also seen preconditioning use nothing but traction pack while plugged in, but I've also seen a lot of other conditions I don't understand yet happening while charging and driving.

 

Instead of creating a new thread..I'll piggy back on this one.

I have '14 Prius (base). I'm looking at upgrading soon and debating between Camry Hybrid, Prius and Prius Prime.

My daily drive to work is 54 miles (2 miles city, 50 highway, 2 miles city). There are no plugs at my work. The plan would be to charge overnight at home.

So my understanding of the Prime is...BEST MPG case is I would get 29 miles electric rest on the regular hybrid cycle. I was hoping "Charge Mode" would up the overall MPG if I'm doing so much highway driving. But it seems its a was in the end.

Am I understanding your testing correctly?

 

I would charge overnight.

But if we all go somewhere together we use the bus (Sienna).

 

I don't use Charge mode nor do much highway driving, but I just do not see any MPG improvement by using the Charge mode. You are using gas to charge the battery which is used to move the car. Any way you do it, it is not going to be energy saving.

That being said, your real MPG improvement will come from the way you drive on that 50 miles of highway. If that's all going to be 70+ mph, it's going to be hard. But if you can do less than 50mph (even a portion of the travel) and the terrain you are driving have some ups and downs, mixing HV and EV for daily 100 miles drive can improve your EV range up to ~50 miles. That will increase your overall mpg substantially.