Best Techniques to Drive the Prime

I'm sorry all, I thought we would have a definitive answer by now...

Results from today:

• 40 degree weather
• 121.8 mpg, 49.0
• This technique did not exist in my PiP.
• 67 % EV Usage
• 45 MPH Average Speed
• 1:05 elapsed time
• No Miles Left EV

What I did...

Did not push EV above the halfway point. I have a really long ~5 mile uphill grade. But I don't have to throttle too much as it's a slow speed limit and windy. I'm able to make it to the top of the hill and then there I hit charge mode. I noticed that running it in Charge Mode downhill first caused the engine to warm up and the mileage is actually reflected more-or-less correctly (ie, downhill yielded me 50 MPG as the engine warmed up AND charged the battery). At the end of the downhill it finally went 100+ MPG.

Going downhill in chargemode still yields 100+ MPG, and I think the car is being charged by rolling and engine. I did this 4 times in downhill grades that were > 1 mile. I pushed into HV mode if my throttle required more than half way power. Note that EV auto still allows you to go beyond that.

Other thoughts:

• Some people say, charging the car through charge mode is inefficient, because it's inefficient to convert gas to electric. But take into mind that's what the Hybrids do. It's able to balance it out, so perhaps rolling downhill and charging is not a bad idea.
• Note my EV usage drop, most likely because EV was off most of the time especially down hills.
• Note my speed increased.
• Note outside temperature increased by 4 degrees. Not sure if this matters but it could be that the heat pump didn't need to run as much.

Any other thoughts?

So it seems on a downhill grade you could run in charge mode to charge your battery faster. You'll achieve perhaps 199 MPG vs 999 if the engine is off. But overall if you use EV efficiently it may benefit you in the end.

Next few tests will involve repeating the results, paying attention to the weather and seeing if they match and are consistent.

What's great is after all these tests I'm still over half a tank full.

Need to definitely pay attention to the temperature though! And I think in the summer the engine warmup may not matter as much!?

It's crazy to get 4-10% variance here depending on technique. My gas consumption at this rate could last me an extra 2 days. This is exciting. Interesting car!

 

So I think downhill in ev mode and hv mode is similar. You won't lose charge. Initially when the motor needs to warm up it seems to propulse the car less and rely on ev motors as well. But only if you gas it.

Charging regen in hv or ev mode is the same. One may require engine warmup though and use the gas. But then it'll be warmed up at the bottom of the hill and you can go! So if you need to be in hv mode at the bottom pressing it at the top of the hill is probably the best for saving ev range and gaining it.

 

More figures here, FYI, the strategy here was to get to the top of the hill, reset the Odometer. Go down the hill in two different methods. Drive in HV and use up the EV range to when I started.

Here are my results (FYI the downhill is a steep grade for 1 mile).

Charge Mode Downhill Method

• 5.2 miles driven
• 52.8 mpg
• Got about 2 miles EV regen.
• Note that I went further trying to use up the EV range and actually switched to EV mode when the rolling hills started. I didn't want to taint my results, but I obviously did.

HV Mode Downhill Method

• 3.4 miles driven
• 63.4 mpg
• So HV mode used up about 1 mile EV gained, shorter distance got 63.4 mpg.

Average temperature both times: 27 degrees F.

I notice when I have the front heaters on that activate the engine the car actually does pretty well. I wish EV Auto was more conservative with the EV usage, it seems to have a high tolerance unless you absolutely floor it...But with front heaters and going back home with 50 miles to drive I averaged 88 MPG. Engine on and off to warm up the car. And it was nice because I didn't have to switch modes back and forth and still had EV at the end of my trip. My % EV dropped from 75 to 50 but it was still great in cold weather.

 

How would I find that out? Something external right? And from the wall?

 

In my tests, yes; better as in better fuel economy. However, this is not the end of it yet. It's important to note that it took longer to use all the EV range generated by CHARGE Mode, and I did force it into EV to use up the range whereas going down in HV mode I used up the 1 mile generated easily. A better test would be to not charge the car in the morning. Run the test for the same amount of miles and see what happens. I should have enough gas to do that ;D