Keeping EV battery 40% full?

Not as such, but you can toggle over to HV and it won't use up your remaining EV miles until you toggle back to EV.

 

The Prius has plenty of supplemental power from the engine so there is no need for a mountain mode. In the rare event you are in a very cold situation with a very steep and long incline you may run the HV battery down such that you are basically running on the engine alone, you still have enough power to maintain a respectable speed.

 

I read a little about the Volt's Mountain Mode. Putting the Plug-in into HV mode is the equivalent, except that the Horsepower of the Plug-in does not change depending upon whether it is in EV (electric-only) or HV (hybrid) mode. In HV mode, the car uses a separate set of battery cells and operates just as a normal Prius does. Also, if you put a Plug-in with a full battery into HV mode, the Prius will consume about 20% of the EV battery capacity. I'm not certain why this is, but I think it is to allow the engine to warm up with as little load as possible, in order to reduce emissions.

Using Prius EV mode is different from using Volt's Mountain Mode. In the first place, the Volt apparently has more horsepower available in electric drive mode, while the Prius has less; at least, the top electric-only speed of a Prius is only about 62 MPH. The second difference is that Volt owners apparently use Mountain Mode in city driving, because Volt gets low mileage in City driving. The Prius, on the other hand, gets excellent mileage in City driving, as long as you drive efficiently.

 

And if that fails, you have the wife get out and push. Those grids in the rear window are to keep her hands warm in the Winter.

 

There are two batteries, one for EV and one for HV? I must have missed that in reading about the Plug-in.

I often go in to the HV mode with a nearly fully charged EV battery. I do this going up a hill to save the EV for more efficient operation in the flat lands. Yes the ICE goes on and warms up to 130 degrees but the SOC drops only a little. The SOC range on the EV battery is 85% at full charge and 20% at lowest level. A 20% change in EV battery capacity is almost 1/3 of the total operating range, that doesn't seem right.

 

PiP will hold the charge in HV mode. By default, it starts in EV mode.

When the battery is full (85%) and you switch to HV mode, the car will continue to discharge as much as possible blending with gas engine, until it gets to comfortable (about 70%) SOC. I believe it is done to leave room for max regen and prolong battery life by avoiding high SOC duration.

So, it can hold the charge anywhere from 23% to 70%. You will need an OBDII reader to read the actual SOC though. Car only displays EV miles estimate based on your historical data.

 

There is only one battery pack in the production PiP. The prototype had 4 subpacks with one dedicated for HV operation. The production version has only one and I think the software just limits the power in HV mode.

 

I suspect you are remembering details about the Plugin Prius prototype. The 2012 Plugin Prius uses a single common battery pack so the HV mode uses the same battery cells as the EV mode.

I think.

 

I am unaware of anyone using Volt's MM for city driving, except when they want to have heat sooner (for pre 2013).
2013 added "Hold" mode so MM is no longer a game for getting heat from the ICE.

I think you are confusing posts where people with pre 2013's say that for longer trips >>40miles) to use MM for the highway segment and keep some battery/EV for the city portion at the end of the trip. This has multiple benifits, as on the highway@65 MM provides me 42-50MPG because it can use the more efficient mode 4 (actual parallel-hybrond mode) while in city it uses serial hybrid mode which yields more like 35-37MPG. Also engine mode is less noticable at highway speeds than in city driving.

 

A quick experiment supports this. I went directly into HV mode with a full 85% SOC. In a short 5 mile trip, avoiding EV operation, the SOC ended up at 75%. I expect a few miles more would have reduced it to the "comfortable" 70%. I'm not sure why anyone would want to do this in normal operation. Use the EV capacity while you have it and do your EV capacity "saving" (like going up steep hills in HV) at the lower SOC levels.

 

With the 150K miles or 10 year warranty I don't worry about battery life. I do drain the battery SOC down to the 20% to 25% level in order to make the most of my cheap nighttime electricity for charging..

 

I live/work less than 1/2mile from the freeway so it would be nice if I could switch the HV mode early and not use up EV range.

I start with an EV range of 10.6+ but after less than 1 mile of driving I am down to 8.6 miles of EV range or less.

 

Acceleration in EV mode sure use up EV range. If you switch to HV mode on a full charge, your EV miles will still be used up, until the battery gets to the comfortable SOC. Well, that's my observation.

 

Mine too. Even if I switch to HV Mode before leaving the garage my EV miles will be used.

 

Pretty sure the CaliforniBear is a Prius driver..

A weak battery in the hybrid may have a huge impact on milage. On the volt it will impact pure EV range.

I expect that by 2021, when my Volt is 10 years old, my batter will be weaker, and I'll only get 30-35EV miles compared to the 40-50 i get now (a bit less less in winter), and I'll have to charge at work to make it R/T without gas.

Warrantied Volt battery loss at 10 years/150K (in CARB states, 8 years/100K in non CARB) is < 30% , and if many cars reach that level, then they would have lots of warranty repairs so that number should be conservative. I'd expect the average to be 75-80% capacity then. And I'm taking good care of mine in a mild climate so I expect to be on the high side of the distribution.

The Volt's low SOC where the engine kicks in, which I see only on longer trips, so maybe 20 times a year, is 21% raw SOC, which is still in the safe zone for Li-ion longevity. More important is managing the extreme temps, especially at "full" charge (which is 86%), which the volt does well with active management.

 

Honda's single motor IMA is not known to baby the battery. For the manual transmission Insight, it is up to the drive to take care of the battery health by not discharging it too deep. I am not attacking your car, just discussing the points.

Two motor full hybrids (and plugins) like Prius, PiP, C-Max, Energi and Volt can maintain the battery SOC on-demand with the dedicated generator.

 

That "mountain" mode was basically a way of preserving the EV marketing approach with Volt. Committing to only a single locking point didn't compromise the efforts promoted prior to rollout. GM has since changed their stance and finally offered a HOLD mode, which allows greater flexibility with EV depletion... what the plug-in Prius offered all along.