[tacman7]

I wish they could change the way mountain mode works, combine mountain mode and hold mode.

Hold works pretty good but I would like it if it would not just hold but build up more reserve like mountain mode is supposed to do, when possible.

If I have any battery left mountain mode just uses the battery.

I haven't used mountain mode that much, I guess if I kept going it would use all the battery then build up some extra charge.

Could I get that by Monday?

 

[edk-austin]

The gen 1 ICE can only provide about 55KW, so if you're depleting the battery at a 100KW rate, and ICE is providing 55KW, you'll quickly get into Reduced Propulsion, if the battery was at the low point. But if MM is holding the battery at 40% SOC (state of charge), there is plenty of buffer to allow the 55KW to catch up, on average, as you won't use 100KW continuously.

MM IS Hold mode, just at a higher SoC. (and it will re-charge up to 40% if you turn on MM at a lower SoC).

 

[Loboc]

Hold - holds the battery at the SOC when it was engaged.
Mountain - keeps the battery at a fixed SOC. If below the fixed SOC, it will charge the battery to the set point.

In virtually all driving conditions, the generator has enough power to drive normally. Unless you’re climbing Pikes Peak, you should never have to build up extra reserve.

SOC = State of Charge

 

[jsmay311]

So you want to be able to waste gas and completely recharge the battery by burning gas in the engine.

Why in the world would you want to do that?

 

[freshcut]

MM works just as it's designed and is basically a "hold" mode for 40% of the charge or so but with the added feature that if it's lower than that the ICE starts up to put enough energy into the battery to bring it to 40%. The standard hold mode just maintains the charge, however if you engage hold and proceed to climb a steady grade that requires more power than the ICE can provide, it will dip into the battery charge the same as MM does and from my limited experience doing so, I'm pretty sure it will regen back to the set point you initially had for hold mode. The engine however does not run until that's achieved but rather relies on regen through coasting/braking to rebuild the charge if I recall correctly. Next time I take a climb in mine I'll see how it works, but pretty sure the ICE doesn't work as a generator to build the SOC back to the hold set point in hold mode, only MM. One note though is as jsmay311 mentions, it is definitely a waste of gas doing so as the engine not only has to provide power for motion, but also produce excess electricity to charge the battery which requires the engine to run at a higher RPM than normal and burn more fuel than necessary.

 

[viking79]

I have thought they should be the same for a while, make hold mode into charge and hold at user set percent mode. So you would set hold at 40% instead of using MM. Or something to reduce the number of modes. I think the i3 REX works this way in Europe.

 

[SteveSeattle]

Hold mode will use the engine to recharge up to the SOC that was present when you pressed the Hold button. It immediately enters hybrid mode (charge sustaining) and the engine will start soon after.

 

[tacman7]

So you want to be able to waste gas and completely recharge the battery by burning gas in the engine.

Why in the world would you want to do that?

I like driving around the city without the ICE going.

On my longer journeys (like half day) I drive on freeway to one city and run around there then drive to another city on the freeway and run around there and repeat.

I guess I like to avoid running the ICE hard, don't like to hear it roaring (it's not that loud). I like to get up to freeway speed then go on hold and cruise along.

I manage my trips so I wind up getting home with an empty battery.

So I may be just babying the ICE.

But there's times when it could be charging some more without working too hard.

If they're going to quit making Volt's there might be some software engineers out of work that could go into business making custom Operating Systems for the Volt.

I can see it now.

Guess that could never happen due to liability issues.

 

[canehdian]

The simplest way to phrase the request is "allow user-selectable mountain mode/hold mode setpoint"
e.g. like you can flick cruise control up and down incrementally, let the user do the same with the current battery hold point.

It likely won't happen. But software-wise it should be rather simple: Perhaps when you press the mode button (and it pauses for a few seconds to give you a chance to cancel if you don't want that mode) if the user were to flick the cruise control stalk up or down the setpoint line on the driver's display would move up or down a bar (and the computer would run the engine to that particular setpoint behind the scenes). Once you stop selecting, after the two second pause, it would acknowledge the new mode setting, per usual.

 

[Qinsp]

People have requested this before, a Charge Battery mode, and oddly enough, some PHEVs have it.

It makes the car pollute more, cost more to drive per mile, and wear out the ICE component systems quicker, but not by a huge amount.

I would agree it should be a feature. If I want to charge my traction battery with my gas generator, I should be able to do it.

However, EPA/CARB might not approve.

 

[alfon]

With our 2016 Volt with nearly 26,000 miles I usually push the hold mode when it gets down to 10-15 miles of electric range. Even when down to 0 miles the gas motor seems to have plenty of power going over the coast range, highway 26, the highest pass 1642 feet above sea level.

Also the Volt's gas motor, 2016-2018 year, is quite fuel efficient, per voltstats.net, over 46 mpg in gas only mode with 7,000 miles on the gas engine.

I don't use the mountain mode function but Its nice to have in case I choose to.

How many cars with just a push of a button you can go from an internal combustion engine to 100% electric propulsion, and then have the ability to go anywhere from a few miles of electric to perhaps over 60 miles depending on weather etc?

 

[tacman7]

I try and keep half the battery until the last leg of my trip back to the barn.

If I have to park in 110 degree heat it has the battery to run the air and keep itself cool.

 

[wordptom]

Perhaps a bit of historical background would help clarify the relationship between Hold and Mountain Mode.

The 2011/2012 Volts had no Hold Mode. In Europe, the Ampera had City Mode, intended to enable drivers to preserve use of the battery for driving in Low Emission Zone urban areas that were being established, where use of internal combustion engines was either forbidden or subject to fees. The US had no such zones. Hold Mode first appeared in the US in the 2013 Volts. It allowed owners more control over when to drive on grid battery power. Use of Hold also complicated the tracking of Electric vs Gas Miles information as shown on the Energy Usage display.

What the US did have in 2011 was a very wide range of terrain that might be encountered by a Volt driver. As edk-austin points out, when the Gen 1 Volt is running on gas-generated electricity in high power demand conditions, it may need to draw power from the battery to maintain performance levels, returning it to the battery (by recharging) when demand is less. If the fully depleted battery cannot provide sufficient "borrowable" power, the car may enter Reduced Propulsion Mode until the demand is reduced. (The more powerful engine in the Gen 2 Volt significantly reduces this risk.)

GM, in effect, created a "Hold Mode hold point" at a predetermined battery state-of-charge level that would provide this sufficient quantity of "borrowable" power. They also implemented a "feature" that would allow the Mode to recharge the battery back up to this level if the battery soc was already below this level, or even fully depleted, before the Mode was chosen. This feature eliminated the need for a lengthy recharging stop before heading into terrain where the enhanced battery buffer may be needed.

Because the driving conditions under which high power demands are encountered are most likely to found when driving up long, steep hills (e.g., attempting to pass while traveling at freeway speeds up mountain roads), the Mode was named Mountain Mode. Under normal driving conditions, the Gen 1 Volt can recharge a fully depleted battery to the MM-maintained level in ~15 minutes. That’s why the manual says to switch into MM about 20 minutes before reaching the mountains. It’s also important to remain in MM (or Hold) until the final summit has been crested to make sure you have enough battery available for the final uphill drive portions of the trip.

Note that you may switch into MM at any time, even when the battery is fully charged, but if you do before the battery soc has dropped to the MM-maintained level, the Volt will remain in Electric Mode running on grid battery power until the soc drops to the MM-maintained level. At that point, the ICE will start and you’ll switch to using gas, and the battery soc will be held at that point, just as if you had switched to Hold at that point.

In GM Chief Engineer Pam Fletcher’s video discussing the 2011 Volt Drivetrain, she comments that it would be defeating the concept of minimizing gas use if MM was programmed to recharge the battery beyond the buffer deemed sufficient to maintain performance under high demand conditions. Most owners also find that it’s cheaper to recharge from the grid at home than it is to recharge using gas via MM.

 

[Loboc]

I took a Cadillac survey a couple months ago that implied a “Charge” mode for CT6. IOW, exactly what this thread is about. I could see this need in a chauffeured situation where the passenger wants EV-library-quiet operation.