[Patrick Randall]

I've been driving my 2015 in Florida for 38,000 miles and not really used MM. When I tried it very early on, I thought that the engine started up and charged the battery. The car has just come back from service (failed ICE radiator) and now, when I select Mountain Mode, the engine runs but battery estimated miles doesn't increase at all - in fact it decreased from 37 to 33 in about 8 miles.

Is this right?

Sorry, I should be able to answer this myself from the manual but it is a bit vague (to me anyway!):

"The engine may run when Mountain Mode is selected, depending on high voltage battery charge, to build reserve battery charge for uphill climbs. If Mountain Mode is entered with a sufficient battery charge reserve, the battery charge reserve will appear grayed out and any battery charge reserve still unused upon exiting Mountain Mode will return to normal appearance."

 

[Barry]

I don't think you understand how mountain mode works. It does not charge your battery when you already have 37 miles of range. It only charges your battery if it is almost empty. Then it only charges it a little bit, up to about 14 miles of range approximately.

Try it again when your battery is empty and see what happens.

 

[Patrick Randall]

Barry, aha! Thanks - thinking about it, when I tried MM years ago, when picking the car up, the battery wasn't full so your comment makes a lot of sense. (The only reason I was trying MM was that the dealer had just replaced the ICE radiator and disturbed the other radiators so I thought I'd better drive about on ICE for a bit to make sure they'd done a good job - used Hold Mode instead and worried all the way home!) Thanks so much. Have to drive on a little trip to the other coast next week and didn't want to have only electric power out in the middle of Florida. Lovely to have the Volt back - they gave me a nasty new Equinox as a courtesy - ugh)

 

[Barry]

Yes, hold mode is what you really wanted instead. Glad you worked it out.

When you leave on your trip, select hold mode immediately. Then if you break down, you can still drive on the battery for another ~38 miles to get away from the alligators and pumas.

 

[bjrosen]

Hold keeps the battery at the same level, Mountain Mode keeps it at two bars. If you are above two bars it does nothing, if you are below it runs the ICE until the level is two bars. When I'm on long trips I always use Mountain Mode rather than Normal. By using Mountain Mode the car always has electricity when you need extra power, for example of you want to stomp on the accelerator to pass someone. It also means that you can switch to Normal when you are off of a superhighway and drive for a while on the battery which is quieter than the ICE at low speeds. On a highway road noise is louder than the Volt's engine so I don't mind using it when I'm doing 60 or 70, but on ordinary roads the Volt has conditioned me to find engine noise annoying.

 

[wordptom]

The Mountain Mode maintained battery buffer for the OP’s 2015 Gen 1 Volt is ~4 bars. The more powerful engine in the Gen 2 Volts reduces the chances of experiencing a driving condition under which a high power demand might occur that cannot be met by the generator output plus available battery buffer, so the Gen 2 MM buffer is only ~2 bars.

 

[hellsop]

The Mountain Mode maintained battery buffer for the OP’s 2015 Gen 1 Volt is ~4 bars. The more powerful engine in the Gen 2 Volts reduces the chances of experiencing a driving condition under which a high power demand might occur that cannot be met by the generator output plus available battery buffer, so the Gen 2 MM buffer is only ~2 bars.

Which is like ... 12 miles, on a Gen 2. It's still closer to the same number of electrons than might be though just counting meter bars.