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How much do people use mountain mode?

The reason I ask is that last weekend I managed to get the propulsion power reduced message again. This time though I think it was for the 'expected' reason of not engaging mountain mode when I should have done (rather than the previous faulty battery reason).

I know people have stated elsewhere that there aren't any mountains in the UK that need mountain mode, and I wasn't even in mountain country, but the Chilterns do have quite a few steepish hills. I drove in CS mode along the B4507 from Wantage, passed White Horse Hill to near Compton Beauchamp, stopped for a bit about 50 metres down the hill from the main road, then I reversed back up to the main road, turned round and drove straight up Knighton Hill (which is the road leading to Waylands Smithy) and climbs about 80m in half a kilometre.

My guess is that the initial drive along the hilly B road left the battery near its lower reserve, I then turned the car off before it could restore the battery charge, compounded the problem by reversing a significant distance up a steep hill (I'm not sure here but suspect it may not recharge when reversing) followed immediately by a drive up a fairly long steep road. None of that sounds particularly drastic on its own which is why I think it must have been the combination.
 

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I've not used mountain mode myself, I've never encountered a situation locally where I would think it's needed. I live near the South Downs and Harting hill is pretty steep but most of my driving is done on the battery only.. I've not had to deal with several steep hills while running on the petrol engine.
 

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I was doing a 120 mile trip last weekend and decided to use hold with about 7 miles battery left. I accidentally selected Mountain and it went to petrol and the battery registered 0.
Was this right? Not sure what was going on - any enlightenment?
6000. 152mpg
 

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MK AMP said:
I was doing a 120 mile trip last weekend and decided to use hold with about 7 miles battery left. I accidentally selected Mountain and it went to petrol and the battery registered 0.
Was this right? Not sure what was going on - any enlightenment?
6000. 152mpg
Weeeell... In theory, engaging mountain mode expands the amount of the battery that's reserved for the buffer, I.e the amount that's normally left in the battery when you've been running in normal mode and run the gauge down to 0. So I guess that if you engage mountain mode when you still have some miles left, they'll be 'absorbed' into the expanded buffer. Just guessing!
 

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I have played around with mountain mode a fair bit.

My company still have not intalled any charging facility at work even though I have had the Volt for 6 months and I made the proposal for the £2,000/year fuel cost savings 3 months before it was delivered! Therefore I am running almost entirely on petrol only charging when I get an opportunity such as at hotels.

What I have found is that if placed on mountain mode the battery immediately shows 0 whatever range it showed previously in normal mode. If left on Mountain mode for a while (say 30mins) it will charge the battery to about 10 to 12 miles range and then work in the same way as hold mode does, i.e. using battery at low speeds and then firing up the IC to run the motors and top the battery back up.
If you switch back to normal mode sometimes the battery range still shows 0 (but it then runs on battery for about 10 miles) and sometimes it shows the 10 mile range. I cannot work out any logic to the circumstances when it does either of these. If it does show 0 you can simply power down and back up again and you then see the correct 10 mile battery range.

Ultimately mountain mode is pretty pointless unless you have an empty battery and you know you are going to drive in an environment where both IC and battery power are needed i.e. a long run of very steep hills.

Another thing I discovered while playing with modes recently - after charging at a hotel I had 28 miles range on the battery in the morning (it was really cold) but I was running for the 300 mile return journey on motorways in hold mode. Each time I slowed down on a slip road I selected normal mode and watched the battery range increase, ultimately to 50 miles! I guess the computer was registering those decelerating periods as miles run on battery with the added boost of regeneration braking.
Of course once I started to run on battery in town the range quickly dropped from 50 to 28 once the computer had sorted itself out again.

At least I had some entertaining fun on the journey.
 

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Thanks Andy, I read this with interest. Nw for another query on a related matter.
Over the last coupe of days I ave ad a run of 46 miles, but the battery is currently giving me around 33 to 34, especially if my wife and I want some heated comfort!
So, on longer faster stretches, as I know I will need to use petrol, I have popped it into hold, wacked the heater up and then reverted back to battery for the restricted speed bits of the journey. It robaby makes little difference to what I actually achieve on the whole journey, but like you, it entertains me and I am constantly looking at battery range these days.
Anyway, when I get near home with say 8 miles of battery and put it on hold the battery registers 0 and the blue petrol icon stays on when I try to switch back. However, the power flow still says battery, despite the petrol icon. This might be fair enough as a bit of a software glitch but, getting to the point, what is odd and annoying is that despite running 8 miles on battery the overall statistical dipay does nt register these miles as battery driven, the petrol icon over-rides the stats and says I am using enrol although I am not. As I am trying to drive up the lifetime stats I find this really annoying and in future will simply drive until the battery dies. Anyone else noticed this?
6000 miles 152mpg
 

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I have never seen the glitch with hold mode, it only ever happened for me when moving from mountain mode to normal mode.

I've never monitored the statistics while the glitch was active, so I can't say if it registers the correct power source or not. Perhaps I'll try that on the next long journey in order to pass some time.
 

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A quick thought for your consideration. I have a 2012 Volt here in the USA so I have no Hold mode as you do in the UK. Most of the discussion has been around the battery icon and the petrol icon you view on the screen in front of the steering wheel. I would suggest you look at the center screen on the power flow of the T shaped battery icon.

When I switch from Normal to Mountain Mode at anything less then 12 miles of battery left the battery icon goes away and the petrol icon shows up on the screen in front of the steering wheel. If I look at the center stack screen however with the power flow T shaped battery icon the same number of electric units continues to show up for about a 12 mile range. In short the status of the battery electricity available to my Volt stays the same in the center screen display while the screen in front of my steering wheel reflects where my Volt will be drawing energy from on anything more then my 12 mile buffer that mountain mode requires.

Hope that makes sense.

Ross
 

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Thanks Andy, I read this with interest. Nw for another query on a related matter.
Over the last coupe of days I ave ad a run of 46 miles, but the battery is currently giving me around 33 to 34, especially if my wife and I want some heated comfort!
So, on longer faster stretches, as I know I will need to use petrol, I have popped it into hold, wacked the heater up and then reverted back to battery for the restricted speed bits of the journey. It robaby makes little difference to what I actually achieve on the whole journey, but like you, it entertains me and I am constantly looking at battery range these days.
Anyway, when I get near home with say 8 miles of battery and put it on hold the battery registers 0 and the blue petrol icon stays on when I try to switch back. However, the power flow still says battery, despite the petrol icon. This might be fair enough as a bit of a software glitch but, getting to the point, what is odd and annoying is that despite running 8 miles on battery the overall statistical dipay does nt register these miles as battery driven, the petrol icon over-rides the stats and says I am using enrol although I am not. As I am trying to drive up the lifetime stats I find this really annoying and in future will simply drive until the battery dies. Anyone else noticed this?
6000 miles 152mpg
Yes I have.

I try to use petrol only above 60mph which is usually motorway miles. I switch between hold and Normal and I have found that sometimes I lose mileage on the battery, it just changes to zero and wont switch back over, I can lose up to 8 miles like this and I stay on petrol for the remainder of the journey plus I also do not get to use my full 10.6Kwh of battery.
On the flip side though I have seen my Kwh usage go over 11 on one full charge before!
5000 miles 110mpg
 

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@Vince Lewin hope you noticed that this thread is over 2 years old. I have noticed what you say but only when down to about 1 or 2 miles electric range remaining. I have noticed it dropping from about 4 miles to 1 whilst parked up at work before I take it to charge up at lunchtime.
 

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I also do not get to use my full 10.6Kwh of battery.
On the flip side though I have seen my Kwh usage go over 11 on one full charge before!
There are other threads where the accuracy/reliability of the "kWh Used" is discussed. Don't put too much trust in that number because it's only an estimate - the same as the battery-miles gauge indicator on the driver's console (as well as the petrol-miles gauge). All of these are estimates.

One might think that kWh Used could be accurately measured, but it's quite complicated, and I won't get into it here. (Feel free to look at the other threads for that.) That reading is merely trying to tell you about the energy usage for the trip as a whole. That's why regen will reduce the number. What that reading is *not* intended to do is to tell you about the health of the battery.

I will say this, though, since it seems to be relevant to your comments... if you park and turn off the car for a period of time then the car has a chance to accurately measure the charge on the batteries. It may need to make some adjustments. In such cases the adjustments to the SOC are not reflected in the "kWh Used" reading.

If you want to test this compare the "kWh Used" readings in the following tests:

1) After the charge is complete disconnect the charging cable and let the car sit for a day before driving it. Compare that to driving it immediately after the charge completes.

2) Before making a long trip make a short 2-mile trip and recharge the battery before departing on the long trip. Compare that to doing the same trip but without the short preceding trip.

3) Drive until about 2/3rds of the battery is used and then stop for an hour. Then finish using the battery in a trip. Compare that to driving the same trip but without the hour stop.

4) Drive until about 2 miles of the battery are left. Then stop for an hour. Compare that to the same trip but without stopping.

In all of these scenarios you're likely to see noticeable variations in "kWh Used" as well as some less-noticeable variations in the battery range covered. That is all without using Mountain Mode or Hold Mode - both of which will complicate things even further.

All of this is to say that the system is complicated. Maybe there are some bugs in there, but most-likely there is just some complication to the way things work that is influencing what you're seeing.
 

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Don't worry, you don't 'lose' anything! If you hit hold or MM when you only have a couple of km left, that will get consumed into the buffer. When running on petrol, the battery will vary up and down by 400Wh or so, with the engine starting and stopping (if you're drawing less than 12kW on average). The battery will discharge, then recharge. If you are so close to having an empty battery that the buffer will cross the 'zero' point, it is all drawn into that buffer and used as if you were now at zero batter, i.e. as if your battery had exhausted and the engine had started up.

What would normally happen is that if you run the battery to zero in 'normal' the engine will crank up and fill the buffer with around 400Wh before powering off again. So you simply 'enter' that cycle at that point instead.

There is a significance to this that you might like to bear in mind - as you say, very wisely aim to use the engine when over 60mph. This means the power train will go into 'power-split' mode where some of the ICE power goes straight to the driven wheels and does not circulate through the electrical system. This is about 10% more efficient than serial mode, which is again about 10% more efficient than charging the battery up. However, if you let the battery go flat just as you get close to your destination so the engine fires up, it might well put more energy into the buffer than you actually need. It is better that you generate enough energy at 60mph to complete your journey with 1 or 2 miles left than to over-cook it and cause the engine to fire up just at the last moment.
 

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So, yesterday I made my usual Friday-evening drive of ~60 miles and decided to mess with Mountain Mode for the first time when not driving on a mountain. (Remember that this is a MY2012, so there is no Hold mode.)



This trip is between my home and the city. It involves ~7 miles of rural 40 mph driving before reaching the freeway, ~18 miles of freeway driving at roughly 65 mph, ~3 miles of city driving to reach the destination, and then a return.

I enabled Mountain Mode as soon as I got onto the freeway at 60 mph, and then I returned to Normal mode when I left the freeway into the city. Again, I enabled Mountain Mode when reaching the freeway at 60 mph, and then I returned to Normal mode when I was ~13 miles from home (which left me with 2 miles on the GOM when I arrived).

I'm not terribly impressed. As you can see from other posts with roughly the same trip (but where I just leave the Volt in Normal mode the entire time), the fuel economy wasn't phenomenal and may actually be less than I usually see (even though the ICE kicks-in during city and rural driving). I was hoping/expecting to see something like 125 mpg, which is more in-line with what can be seen if I "overcharge" the battery due to a short preceding trip.

Obviously, the mpg isn't terribly bad (am I really moaning about 101 mpg?), but at first glance it would appear that the effort of switching into Mountain Mode really was a waste of time and effort.

Did I do something wrong, or should I just let the Volt manage things on its own (like I have done before)?
 

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Before I found a place to charge up near work I was travelling around 106 miles daily. I would use electric power for the first 10 miles until I reached a dual carriageway (not quite a freeway) then motorway (freeway) and use Hold mode, then back to electric around 6 miles from my destination during slowish and stop start traffic. Return home was reverse although I would switch back to electric when the distance to home was just more than the electric range to make sure it was all used up and this gave me an MPG figure of around 96 - 98. I thought this was better than using all the electric up on the morning commute and some petrol and having to use petrol during some of the crawling slow moving parts of the trip. The only thing I can think of is that the Mountain Mode is trying to keep the battery state of charge higher than the Hold which just holds whatever is left but I would have expected it to balance out.
 

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After another go yesterday with using Mountain Mode as described I can see that to beat the fuel economy that you'd otherwise see in Normal mode that it's extremely important to switch off of Mountain Mode when nearly exactly at the point where your battery will be "empty" when arriving home. If you can't get it that close then you may as well let the car do its own thing in Normal mode. Even driving a couple extra miles in Mountain Mode on the motorway will end up costing you.
 

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it's extremely important to switch off of Mountain Mode when nearly exactly at the point where your battery will be "empty" when arriving home. If you can't get it that close then you may as well let the car do its own thing in Normal mode. Even driving a couple extra miles in Mountain Mode on the motorway will end up costing you.
Yes, that is very true. The art is to make it so that you end up with 1 miles left showing. Zero and you have risked causing the engine to start up, and when it does it'll immediately burn enough to create a net positive buffer, which is then wasted because you'll be charging the car up next rather than using that buffer. More than 1 mile remaining and, well, you've run the engine too much!

OK, so I push to zero miles left, and even get it so that the fuel symbol comes up. When it does, if you feather the pedal and don't exceed 20kph then the engine stays off and you can eat up around 400Wh of the buffer below the 20% level (i.e. drain a little more from the battery).

Did I do something wrong, or should I just let the Volt manage things on its own (like I have done before)?
Possibly! When did the engine actually start up during your trip to work? I guess it would have been quite close to when you would have got off the highway anyway? So you've ended up with two warm-up cycles. Let's start there, and I'll think about what I'd do without hold.
 

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Possibly! When did the engine actually start up during your trip to work? I guess it would have been quite close to when you would have got off the highway anyway? So you've ended up with two warm-up cycles. Let's start there, and I'll think about what I'd do without hold.
In Normal mode in the summer I can make it to the city on battery and then about 5 miles on the return trip before it switches over to charge-sustaining mode. (In my wife's Volt she gets 10 miles on battery on the return trip. Hers is a MY2012 as well, but was built almost a full-year later in December, 2012 - so I'm thinking that it has the 2013 battery.)

I think that I've had two big shortcomings in my two Mountain mode tests:

1) I shouldn't use Mountain mode on the trip to the city provided that charge-sustaining mode will not kick-in before I get back onto the freeway on the return trip. The warm-up cycle apparently consumes a considerable amount of fuel (making it a bigger concern than the efficiency gains to be had in direct-drive). It would be better to only use Mountain mode on the return trip.

2) I really need to figure out exactly where the point is on the return trip where I will have 1 mile left on the battery when I pull-into my garage. Unfortunately, this point will vary depending on the ambient temperature, whether or not I'm heating the cabin, and whether or not it is raining.

So, I will experiment with this a bit more before I give up. However, the variables involved in #2 may prove rather difficult in nailing the 1-mile-left bulls-eye on the arrival home.
 

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Hers is a MY2012 as well, but was built almost a full-year later in December, 2012 - so I'm thinking that it has the 2013 battery.
If it was built in Dec 12 then it is a MY2013, which started on the line in June 2012. Some May 2012 MY2012 also received the 2013 battery. The VIN should say 'DU' before the 6 digit production number at the end. If it says 'CU' I can't see how it was made in Dec '12.


1) I shouldn't use Mountain mode on the trip to the city provided that charge-sustaining mode will not kick-in before I get back onto the freeway on the return trip. The warm-up cycle apparently consumes a considerable amount of fuel (making it a bigger concern than the efficiency gains to be had in direct-drive). It would be better to only use Mountain mode on the return trip.
Agreed. Although you will end up recharging the battery, which is lossy, if you use up more than the MM set point of battery, overall it is probably better just to run in one go.

However, as you are already going to be generating electricity that will go to charging the battery, I would start MM as soon as I get in the car on the way back. With hold I'd never recommend this because it is more efficient to run it at speed, however in your case without it, it isn't. Also, you will get immediate heat and not have to draw on electricity (or at least, not much) for any cabin heat.

So what I would do without hold is never run it on the way, but instead select it as soon as I set off on the return trip.

I suspect if the weather gets real cold this coming winter, I will be doing this myself. In fact I have already been experimenting, but at the moment I have not used up enough battery when I get to work for MM to kick start the engine when I come back! But later in winter I expect I will use up that much battery.

2) I really need to figure out exactly where the point is on the return trip where I will have 1 mile left on the battery when I pull-into my garage. Unfortunately, this point will vary depending on the ambient temperature, whether or not I'm heating the cabin, and whether or not it is raining.
There are variables, but it's not so difficult if you can regularise your driving style. If the traffic is variable, that can be difficult, but assuming you have some control over the driving profile of the car, I would estimate where in the trip I need to select 'normal', by location, and try that. If I get home with spare, then I'd pick an earlier location along the trip the next day, etc.. If I select normal and don't make it home, then leave it to a later spot the next day.

I have a number of set points along my commute I can gauge whether I am going to need the engine or not. For example, I know if I get to a certain bridge on the highway with 8km showing on the range estimator, then I'll make it home. So if it is showing 8km remaining further back, I'll select 'hold' until I get to that point and then go back to normal.

The range estimator is surprisingly accurate when used like this, and I guess it is taking into account the temperatre, heater use, driving style, etc.. I would never have used the range estimator on my previous BEV, but the Ampera shows an uncanny accuracy that is reliable for this style of use.
 

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If it was built in Dec 12 then it is a MY2013, which started on the line in June 2012. Some May 2012 MY2012 also received the 2013 battery. The VIN should say 'DU' before the 6 digit production number at the end. If it says 'CU' I can't see how it was made in Dec '12.
So, I looked at the door sticker again... it was manufactured in May 2012 and not December. It's my Volt that was manufactured in December... of 2011.

But, yes, what you're saying would confirm my suspicions that hers has the 2013 battery.
 
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