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Late next month I'll be making a trip across the country and back (from Arizona to northern Michigan, and some other side trips in between), where I expect to put roughly 6,000 miles on the car over a few weeks. I understand the how, and the when, to use MM, but what happens if I forget to use it and find myself crossing a mountain range with zero battery? Is it just a matter of "oh, how annoying..that engine is LOUD!", or am I going to find myself potentially unable to make it up a pass?

I don't really care about the MPG differences, and I'm not trying to "game" the system for extra performance..I was originally planning on making this trip in my F350 truck (and budgeted accordingly), so I suspect that _anything_ I do in the Volt will return better MPGs, lol. But honestly, I'd rather take a few MPG hit, leave the car in normal, and not concern myself with switching in and out of modes.
 

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If you forget (like me), the car losses power. Not the end of the world though, you still have enough power to handle most situations, you'll just have to join the trucks and motorhomes. The ICE runs at about 3800 RPM to spin the generator at max output which is still more than twice the output of the I3, so no worries.

To avoid this just go to MM at least 10 miles before you get to any steep climbs.
 

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Discussion Starter #3
If you forget (like me), the car losses power. Not the end of the world though, you still have enough power to handle most situations, you'll just have to join the trucks and motorhomes. The ICE runs at about 3800 RPM to spin the generator at max output which is still more than twice the output of the I3, so no worries.

To avoid this just go to MM at least 10 miles before you get to any steep climbs.
Seeing as how I've yet to memorize all the roads I've never driven on, it's likely that if I forgot to turn on MM after my last stop, that I will also not be aware of a steep climb until I find myself ON said climb :D Heck, for that matter, half the time I forget about the mountains HERE where I live until I'm part way up!

I don't care if I'm going slow, I just wanted to make sure it wasn't going to be a situation of being unable to pull a grade, period.
 

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What is the max elevation change along your route? It might not matter if you use MM or not.

I'd run in Hold mode the entire trip. That way there is a little extra oomph since the car can dip into the battery a little more. This worked well for me in the Ozarks. (2013 Volt) Ozarks aren't really 'mountains' like the rockys though.
 

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When on trips, I always use hold mode for highway driving. Then when 50 miles or so from home I go to normal mode to use the battery charge. But while driving in towns and in traffic jams I do use normal mode (although I don't let the battery range drop below half - then I stay in hold mode).

The main reason I do this is to have extra range if I let the gas get too low (which never really happens, but I like the safety net). Also this approach gives extra boost for mountains, etc. if needed.
 

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If it gets bad enough, your Volt will go into reduced propulsion mode and you'll slow down. If that bothers you. You can switch to MM and pull over and let the Volt recharge the battery. Either way, your Volt will get you over the mountain.
 

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It depends on the length of the grade and your speed. 55 mph up a 6% grade pulls about 40-42kW load which is sustainable indefinitely on ICE. 75 mph will tap into your buffer and when the buffer runs out you will get reduced power.

So it's better to have a couple bars of juice before a long climb, and keep the speed down so you have full power when necessary for quick passing.
 

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- you go up the mountain more slowly
or
- you pull over and let mountain mode build up some charge, then speed up the hill at a faster rate.

Makes more sense to me to just chug along at the slower pace the entire time.
Don't worry about it that much. It's a 'nice to have', not 'need to have'. You'll still be able to make it up. It's just a question of how fast.
 

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Think of MM as a method of driving in Normal with the "switch to ICE when battery is depleted" trigger point at a bit higher level...

If you switch into MM with a full charge in a 2011/2012 Volt, the estimated ev range immediately drops by ~14 miles (the MM buffer), and everything from then on operates just like Normal mode... you start off driving on grid battery power, and once the ev range is gone, the car switches to ICE and continues on. Later model Volts will "grey out" the bottom battery bars when you switch to MM. Of course, each time you turn the motor off, you need to switch back into MM when you start the car again.

As you approach the end of your trip, switch back to Normal, regain the use of that ~14 ev miles, and it’s as if you drove the whole way in Normal (and the extra battery buffer will be available if you do need extra oomph when driving up steep hills - if not, nothing wasted, no difference from driving in Normal).

You might consider doing this during the long trip stretches that go though hills - make a habit of switching into MM as you start the day’s journey.

Hold mode will also work (my 2012 has no Hold), but if it’s likely you might forget to switch out of Normal after a stop along the way, you can’t recharge the battery to recapture the buffer by switching back into Hold after you’ve been driving down the road for a while and remember. You can if you switch back into MM.

Last year I drove from Oregon to Michigan and back using this method (not sure if the buffer was ever needed when crossing the Continental Divide). I also like to reset Trip B each time I fill the gas tank... provides an excellent display of my "on the fly" gas mileage (except for the initial setting, no electric miles are included in the total), and how much gas from the most recent filling has been used (I like to refill when 1 or 2 gallons are still remaining).

Note that if you drive long distances between fully recharging the battery, the usage screen display has limits... For my Gen 1 Volt, when the trip total reaches 1272 miles, the Total Miles display freezes at that number (total miles usually includes some electric miles, so this is the first of the three distance display numbers to hit 1272). When Gas Miles reaches 1272 miles, that number, too, stops increasing, although the trip MPG, lifetime MPG, and Gas Used continue to display correct numbers. I don’t think anyone has only partially recharged often enough to see if the electric miles since last Full Charge also freezes at 1272 miles. The entire screen does reset with a full charge. Some say the max display of 1272 miles might be a limitation of the binary representation of the metric equivalent of that distance.
 

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I did a trip to Dearborn last August. From the time I left my hometown limits it was in Hold mode. I never had access to 120v wall outlet at any of the places we stayed. So I just kept the battery above 50% for most of the vacation. Occasionally, I'd Get a green bar with long down hill slopes. Then I would reset the hold mode to capture it for city driving.

Assume that you won't be able the Charge overnight where you stay unless you get lucky and there is an external outlet near your parking spot. Your going to want to use HOLD mode all the time. If you pull a long hill in hold it will act just like MM anyway to maintain the SOC you selected. I can't imagine any upslope being so long that it would deplete the battery in Hold mode if you had at least 75% battery available.


Sent from my iPhone using Tapatalk
 

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So leaving it in hold doesnt keep it from using the battery during long uphill grades?
Nope, if you are in hold mode it will allow the car to use any / all of the battery. For example if you started out with a 50% charge and went into hold mode and then had a 100 mile long 6% uphill road it would deplete a substantial portion of the battery, and then it would re-charge to what ever the SOC was when you entered hold mode (in this case, 50%) as soon as available power from the ICE is more than is required by the traction motor. In the real world there are no grades that steep that are also that long... that is why MM in the 1G Volt maintains about 3.6 kWh buffer and the 2G Volt only maintains 2.8 kWh... in addition to the 2G having more power from the ICE, nobody ever used up all of the buffer in the 1G mountain mode... it was overkill.

Keith
 

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I don’t think you have anything to worry about. You don’t need mountain mode except on the longest, steepest grades, like climbing to a high pass in the Rocky mountains. So for most of your trip, you won’t need it at all. If you find yourself in a serious mountain environment, you will know it by the extreme change in scenery. It should be pretty obvious and will remind you to switch to mountain mode. And if you forget, you will just be a little slower. Not a huge problem.

Also, I’m not a geography expert, but I’m pretty sure if you take the direct route (assuming Hwy 40 out of Az), you won’t have any serious climbs and no need for mountain mode at all.
 

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The toughest aspect of remembering Mountain Mode is that the Volt reverts to Normal every time you stop for a photograph, lunch break, gasoline fill-up, or any other engine shut-down. However, I do not worry much about whether the Mountain Mode is set or not. I just got back from a 600-mile trip to Moab back to the Continental Divide. The extra kick of banked charge does make the ride smooth, but I rarely get a power shortage warning despite climbing 6-percent grade to 10,600 feet for ten miles on Vail Pass. I think I did get a warning once climbing from Denver at 5,000 feet to the Continental Divide at 12,000 feet on an empty bank.
 

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Nope, if you are in hold mode it will allow the car to use any / all of the battery. For example if you started out with a 50% charge and went into hold mode and then had a 100 mile long 6% uphill road it would deplete a substantial portion of the battery, and then it would re-charge to what ever the SOC was when you entered hold mode (in this case, 50%) as soon as available power from the ICE is more than is required by the traction motor. In the real world there are no grades that steep that are also that long... that is why MM in the 1G Volt maintains about 3.6 kWh buffer and the 2G Volt only maintains 2.8 kWh... in addition to the 2G having more power from the ICE, nobody ever used up all of the buffer in the 1G mountain mode... it was overkill.

Keith
Great explanation. If you enter hold at 100% will it try to get back to 100% or stop short? I thought the Volt could never get back to full charge.
 

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In my experience, Mtn Mode and Hold are functionally the same, the difference is that Mtn Mode defaults to a preset amount of protected charge (50ish %). Hold Mode allows you to decide how much battery charge is protected. They both use the battery when need and replace as soon as they're able to.
 

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In my experience, Mtn Mode and Hold are functionally the same, the difference is that Mtn Mode defaults to a preset amount of protected charge (50ish %). Hold Mode allows you to decide how much battery charge is protected. They both use the battery when need and replace as soon as they're able to.
Only mountain mode will deliberately recharge the battery. Hold will work like REX mode, using the battery as a ballast and using excess ICE power to charge the battery (Usually very little).
 
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