[gschuck]

I drive mountains almost every week and I exclusively use HOLD instead of MM. My understanding is that HOLD is exactly the same as MM with two exceptions:

1) HOLD will not charge your battery past the set point whereas MM will charge it to 50%

2) HOLD has a variable set point whereas MM is always 50%.

The engine doesn't care. I use HOLD so that after I climb a grade I can reset the HOLD point so that I do not use gas to rebuild a charge. I know my route so I can manage my SOC without needing MM. Charging the battery with the engine is not as efficient as letting the hold point drop a little on each grade. Note that you should only drive this way of you know the grades to expect and what charge you need to climb them. Otherwise just use MM and don't worry about it.

Bottom line: just drive the car and enjoy. GM has thought it through for you.

 

[Neromanceres]

The Volt gas engine is limited to 4800rpm which is well within its limits. The gas engine is actually treated very well in the car.

I'm not sure how often you have used your gas engine but it's possible that it could still be burning off some of the original factory lubricants.

 

[saghost]

I drive mountains almost every week and I exclusively use HOLD instead of MM. My understanding is that HOLD is exactly the same as MM with two exceptions:

1) HOLD will not charge your battery past the set point whereas MM will charge it to 50%

2) HOLD has a variable set point whereas MM is always 50%.

The engine doesn't care. I use HOLD so that after I climb a grade I can reset the HOLD point so that I do not use gas to rebuild a charge. I know my route so I can manage my SOC without needing MM. Charging the battery with the engine is not as efficient as letting the hold point drop a little on each grade. Note that you should only drive this way of you know the grades to expect and what charge you need to climb them. Otherwise just use MM and don't worry about it.

Bottom line: just drive the car and enjoy. GM has thought it through for you.

This. With the minor caveat that the MM threshold is actually about 1/3 of the nominal charge, not 1/2.

There should be no problem with any slope or speed in Hold mode; the car does run the engine fairly high on steep ascents - but the highest we've seen it is 4300 rpm (except for one mysterious 4500 rpm datapoint someone got at 100 mph on the autobahn) - well below the redline of most other cars.

 

[joheitritter]

I drive mountains almost every week and I exclusively use HOLD instead of MM. My understanding is that HOLD is exactly the same as MM with two exceptions:

1) HOLD will not charge your battery past the set point whereas MM will charge it to 50%

2) HOLD has a variable set point whereas MM is always 50%.

The engine doesn't care. I use HOLD so that after I climb a grade I can reset the HOLD point so that I do not use gas to rebuild a charge. I know my route so I can manage my SOC without needing MM. Charging the battery with the engine is not as efficient as letting the hold point drop a little on each grade. Note that you should only drive this way of you know the grades to expect and what charge you need to climb them. Otherwise just use MM and don't worry about it.

Bottom line: just drive the car and enjoy. GM has thought it through for you.

Thank you so much for your reply.

Two questions:
1) You mention "manage my SOC without needing MM" - what do you mean? What is SOC?
2) What do you mean when you say "know the grades to expect and what charge you need to climb them"

I do not drive in the mountains very often, so I don't know much grades - all I know is that I'm starting at an elevation of about 500 and rising up to about 5600 over 45 miles.

Thanks again, your reply was very helpful!

 

[joheitritter]

The Volt gas engine is limited to 4800rpm which is well within its limits. The gas engine is actually treated very well in the car.

I'm not sure how often you have used your gas engine but it's possible that it could still be burning off some of the original factory lubricants.

Thanks so much for your response!

I don't know much about RPMs, other than the higher the number the more my car is working. When I am going up the inclines it sounds like it's really struggling, so I'm assuming it's just at it's highest RPM - and that's why I was wondering if it was bad for the car. Is it bad for it to run at such high RPMs for that long (some of the inclines are steep and long)?

I have about 10k miles on the car, and use my gas engine every weekend. But maybe it is still just burning off those lubricants. Thanks!

 

[canehdian]

Thank you so much for your reply.

Two questions:
1) You mention "manage my SOC without needing MM" - what do you mean? What is SOC?
2) What do you mean when you say "know the grades to expect and what charge you need to climb them"

I do not drive in the mountains very often, so I don't know much grades - all I know is that I'm starting at an elevation of about 500 and rising up to about 5600 over 45 miles.

Thanks again, your reply was very helpful!

SOC is state of charge - battery level.

http://www.csgnetwork.com/inclinedeclinegradecalc.html
The average grade from what you stated is about 2%
But if there is a particularly steep section, having mountain mode on may help (I've never been on such a drive yet, can't comment on a difference)

4500 RPM is well within safe limits, and will not damage the engine (the engineers wouldn't have programmed it, if so)
If you think its working hard, try the same run in a gas car, it will likely be revving high as well.

 

[gschuck]

Two questions:
1) You mention "manage my SOC without needing MM" - what do you mean? What is SOC?
2) What do you mean when you say "know the grades to expect and what charge you need to climb them"

My drive has two major climbs and two minor climbs. My total distance will be around 220 miles, so I know that I am going to exhaust the battery. My first climb is around 2400 feet over 10 miles, starting around 15 miles in to my trip. If I leave with a full charge, I'll put the car in to HOLD as soon as the speed limit increases to 55 mph -- which is around 5 to 7 miles from the start of the grade. By this time my SOC will be showing 80%. Over the next 10 miles I will lose another green bar or maybe two. At the top of the grade (which I drive up with the CC set to 53mph), I will change briefly to NORMAL and then back to HOLD. This resets the HOLD point to where I am now, say 60%. This is important because if I did not do this, then the engine would work to replenish the 20% SOC that I burned off on the climb. I want to avoid that inefficiency. In another 75 miles or so I hit my next grade which is around 2300 feet over 8 miles. I'll drive this at 63mph (clearly I am not that worried about efficiency after all). I follow the same process. By the top of this grade, I'll lose another two or three bars of charge (putting the car below the MM threshold). At the top I will put the car in to NORMAL to avoid charging the battery with the engine. At this point I have a nice descent that will regenerate a lot of battery anyway (even at near 70mph -- cruise control an L for me).

Because I know where I am going to be driving and how much battery I can expect each grade to use, I can save my battery power for when I need it on the climbs without using MM to regenerate electricity. After driving this route many times I have found this to be more efficient than just leaving the car in MM.

That being said, when I am going on a long drive where I do not know what to expect, I will put the car in MM and not worry about it until I know I am 20 miles from my next chance to charge -- at that point I will run the battery out (unless I know that I have a big grade at the end of the trip).

Please note that this is "gaming". I only drive the car this way because it helps to pass the time -- not because the car need to be driven this way. It is slightly more efficient to this. I'd be a lot more efficient, though, if I drove slower.

 

[jimtesla]

with multiple trips to Vegas from Los Angeles..the car pulls better upgrades in mountain mode....i can keep up the grades no problem in 120 degree plus heat at 70 mph with a full car load and ac humming.......if I use just Hold going up these grades the engine works really hard.....i have seen a difference...this is my second Volt...if its extreme conditions i use the best mode for the Volt....Then I switch to Sport on the downside to regen my loss...I have found Sport mode regains more lost energy going downhill then normal mode..I drive canyons everyday....This Volt is amazing on how everybody can drive differently and find cool ways to get there...

But try Mountain Mode on your drive and you will see a difference in sound and smell......extreme elevations is what it is designed for

 

[konimail]

Thanks so much for your response!

I don't know much about RPMs, other than the higher the number the more my car is working. When I am going up the inclines it sounds like it's really struggling, so I'm assuming it's just at it's highest RPM - and that's why I was wondering if it was bad for the car. Is it bad for it to run at such high RPMs for that long (some of the inclines are steep and long)?

I have about 10k miles on the car, and use my gas engine every weekend. But maybe it is still just burning off those lubricants. Thanks!

You seriously don't have to worry about the engine. It is very well designed and computer controlled to make sure it performs well and for a long time. My BMW can rev up to 9000 RPM and is quite happy to get there

You should not be getting any mechanical smell in the car after 10k miles and such frequent ICE use.
You may want to have someone check that for you.