Charge Loss in HV Mode

[jdonalds]

Not a counterpoint, as much as an observation and data point.

One of our 100 mile drives involves a long climb south out of Tellico Plains, TN. We most often have switched to HV @ 10 EV miles remaining. During that climb, the EV miles drop to around 6.x miles remaining. And the bees start stirring near the top of the climb.

But coming down the other side, EV miles do inch back up to 10, or even 11 or more, and hover around 10 or so for the rest of the trip home.

As an aside, it’s fun going down that same grade the other way - if we’re @ 10 EV miles at the summit, we’re @ 14 or 15 at the bottom. I usually go back to EV for awhile at that point until it’s back at 10.

Probably not a factor, but all this is in SPORT mode with 4 chevrons of REGEN. The one exception is backing off a bit on the REGEN to keep speed up on the long descent.

Yes when you are on a long downhill slope the car will be in EV mode absorbing a lot of regen regardless of which mode is set including HV mode. This can even result in 100% charge whereas HV Charge can not. But to be clear the long downhill regen is different than the HV mode operation where the gas engine is used to attempt to return the battery level to the set point.

 

[jdonalds]

Picture being 1,000 words and all that, the climb I just referred to:

We do live in a beautiful corner of the world. And not by accident - I moved up here from Florida mainly for the wonderful motorcycling roads.

Yep. Lack of mountains was a big factor in us not retiring in Florida.

 

[Landshark]

That is not my experience. When I've driven in HV mode the car can do a fine job of keeping the EV Range at the set point. But with hills, accelerating at speeds below 60 mph, where the EV Range drops significantly it will not recover back to the set point even after hundreds of miles.

Well, we’re clearly having different experiences. I’ve never seen regen on a downhill get the battery anywhere close to 100% based on the gauge, even after 8-10 miles of downhill from 4400’ to 1500’. And that was with the gauge down only 3-4 bars at the summit.

In fact, I have yet to experience it, but some owners report that the ICE will start with excessive regen and a nearly full battery. So it is unlikely that regen will ever get the battery to 100%.

 

[Clarity_Newbie]

Here is some hard data from a recent road trip reference HV mode charge loss/retention.

Results of 4 day trip to Vail Colorado. HV mode entire trip. Normal mode (ie) No Eco/Sport Mode. 97% highway driving ~55 to 75 mph. East to West. ~75 to ~85 degrees, blue sky, variable wind during all drive days.

1562 total miles
51 EV miles at start of trip
17 EV miles remaining at end of trip***

SoC by day
Day 1 - 100% to 81%
Day 2 - 81% to 74%
Day 3 - 74% to 61%
Day 4 - 61% to 31%

***Full disclosure...at peak elevation west of Denver, EV miles was 6 and SoC ~15%. Significant gain descending to Vail. Did use regen at 2 Chevrons to slow decent at times.

OBDII data was also collected for the entire trip. I will post some graphs as times allow.

Hope this helps.

 

[jdonalds]

Well, we’re clearly having different experiences. I’ve never seen regen on a downhill get the battery anywhere close to 100% based on the gauge, even after 8-10 miles of downhill from 4400’ to 1500’. And that was with the gauge down only 3-4 bars at the summit.

In fact, I have yet to experience it, but some owners report that the ICE will start with excessive regen and a nearly full battery. So it is unlikely that regen will ever get the battery to 100%.

We start out at 8,000 foot elevation and ride downhill most of the way to 750 foot elevation. It is so long that starting with 2 or 3 bars (low because of the climb up the hill) it will easily pass the 60% charge the HV Charge is capable of.

 

[BobbyB]

I know you said you have had the car for 'about a month'. Is it new, or did you purchase it used? What year is it?
I would offer one final thing you could try if you are willing. We have found that there is an occasional problem that can be 'cleared' with a hard reset. By hard reset, I mean disconnecting the negative terminal of the 12V battery for a few minutes, then reconnecting. This will cause the vehicle to report a number of ominous sounding errors, but these errors will clear after driving for a few minutes.

So I gave the hard reset a try last night and it seems to have worked. It may be too early to tell, but HV now looks to be keeping the SOC maintained at a set point. I started today with 40 mi EV range and ended at 38 mi.
Thanks everyone for the advice and insight!

 

[David in TN]

Having done a variety of drives: two tanks of gas where I exceeded 3,000 miles, and many trips using more than a tank a day.

Some disclaimers first. I work in IT for Head Start programs in Tennessee, Indiana, Illinois, and Oklahoma. Many of these locations have either a 120-volt plug on the outside or an "RV-plug" on the building. I've never had anyone object in any way for me to plug in. I have a ZenCar 16-amp EVSE with a RV plug adapter as well as a 120-volt adapter. Every hotel I've ever stayed at has let me plug in, too. I have a ScanGauge II which I have setup to show State-Of-Charge (SOC.) SOC starts at 100% and then engine will kick on when it reaches about 10.6%. I'm assuming that is battery management programming.

Here's my "formula" for the best use for me...

Local travel - all EV except when I drive further than my tank of electrons will allow. Then I switch to HV. But my goal is to return to home (or a destination where I can plug in) with 0 EV range left. For example, I live 35 miles from Nashville. If I'm going to Nashville for an event (don't do that much these days with Covid...) then I will drive there on EV, and engage HV on the return trip until I get to approximately 10 miles of EV remaining. At approximately 12 miles from home, I switch back to EV to use the remaining electrons prior to arrival.

Trips - I start in EV mode, then when SOC reaches 80%, I switch to HV. This is done so that I have more regen capacity when stopping or going downhill. While the engine warms up, SOC may drop to around 75%. It usually holds around that 75%. At each stop, there is some EV drop, about 5% is the norm for me, again as the engine warms back to regular temperature. As I approach my destination, I switch to EV, as above, to arrive having depleted my battery.

I'm at 30K miles on mine. My Excel sheet shows that I've averaged about 120 mpg overall since purchased new two years ago. I haven't spent $500 on gasoline yet.

As stated previously by others, the gas mileage shown in the car isn't accurate. Mine has an overall discrepancy of 11%. Meaning that if the car is showing 44.4 mpg, it is actually 40 mpg.

 

[jdonalds]

As long as we are posting numbers...

For the year 2020 we've driven 18 days in HV mode on trips beyond pure electric range. 347 days on pure EV. Spent $276.63 total on gas. Used 91.76 gallons. Drove 20,000 total miles.

 

[rodeknyt]

Well, we’re clearly having different experiences. I’ve never seen regen on a downhill get the battery anywhere close to 100% based on the gauge, even after 8-10 miles of downhill from 4400’ to 1500’. And that was with the gauge down only 3-4 bars at the summit.

Same experience here. A couple of months ago we did a day trip to the local mountains and on the 15 or so mile EV descent heading home, the GOM for EV range went from 37 miles to 92 miles. I was worried that the engine would start with that much range showing until I looked at the battery gauge and saw it was three bars below full. Ran out of hill, so I don't know if it eventually would have filled the battery or not with regen but I doubt it.