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Discussion Starter #1
Has anyone worked out if it is economic to charge the battery using mountain mode?
When the battery miles are used up select Mountain mode and the battery will charge up. If you then stop and switch off and on again then you will see how many miles you have accumulated. In the handbook it says to use this twenty minutes before reaching mountains and so it could need about this long to charge fully.
Geoff
 

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20 mins to fully charge? mmm... That would be about 30kw+ The engine is 54kw so I suppose that even allowing for losses it should be possible.

However, Mountain mode only charges to about 40% so that is probably the most you'd be able to go to.

Whether it is economical to do it I would be very surprised if it was and in any case... why would you want to? Just generate automatically it needs it without storing it in the battery... that has to be wasteful IMO. OK, if you are coming up to a proper, steep hill or mountain and haven't held back any using HOLD mode then you could do it to make sure you maintain performance but I am sure it is not the best way to do it.
 

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Discussion Starter #3
Why would I want to? If I am going to Cornwall it takes about an hour to drive to Taunton and join the M5. By then there are not many battery miles left and so the ice cuts in. So to run in Mountain mode will use more fuel I would be able to use the battery for the last part of the journey. To just use the ice when it could be possible to use the battery is the very reason that I bought an EV.
Geoff
 

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Sorry Geoff, perhaps I am not explaining things clearly...

If you drive to cornwall, or anywhere beyond the range of the battery, then you have a fixed amount of energy stored in the battery and a further amount stored in petrol. With HOLD/MOUNTAIN modes you can choose which to use. So it makes sense to choose to use the battery on slower, in town bits, of the journey and then run the ICE on the motorway, perhaps saving some battery for the town bits at the other end. MOUNTAIN mode can be useful for that because it uses battery to 40% then switches to ICE. I do this all the time on long trips to make sure I have 40% remaining for my slow bit at the end or for the return journey.

Using MOUNTAIN mode in that way doesn't use petrol to charge the battery. It just keeps it at about 40%. If you use MOUNTAIN mode when the battery is already below 40% then the ICE will run and it will charge the battery back up to 40%. To me this makes no sense at all. Using petrol to run an ICE to charge the battery is very wasteful and it will be a lot more expensive than either charging from the mains or just running the car on petrol itself. The reason is that when running the car on ICE the electricity generated can run the motor directly without going through the wasteful process of being stored in the battery then used from the battery.

So MOUNTAIN mode is great for doing what you said Geoff... holding back some battery power (40%) for use later in the journey, but you wouldn't want to use the ICE to charge the battery up unless there was simply no other choice as it is wasteful, and hence expensive.
 

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There is a video from the US on youtube of the very thing you're asking "Self charging Chevy Volt" using mountain mode. The engine ran for 15mins burned 1.38 litres of fuel and charged the battery to 40% then turned off which gave a range of 14 miles.
 

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Reading between the lines Geoff I think you are trying to identify the best utilization of battery and petrol over a long journey rather than just using the GM algorithm..
I see it this way:
Over any long journey we have a certain energy consumption need based on how the vehicle is driven. There are just 3 sources of energy, mains power, regeneration and petrol. The question is how best to use a combination of these sources to satisfy the journey requirement in order to arrive at the destination at minimum cost and/or tailpipe emission in a particular driving style. I suspect that minimum cost and minimum emissions are satisfied by the identical strategy. I believe GM has done a great job in minimising energy use through its software design, but this cannot anticipate the terrain and driving style in a particular long journey.
Over a particular journey, I believe, the best minimum cost/emission scenario will be satisfied by maximising the battery mileage for that particular journey while at the same time minimising petrol use. This implies using the battery in minimum kwh/ mile situations and using the hold mode for the remainder, ensuring the battery is fully utilized at journeys end. Mountain mode is I believe an inefficient way to use the power in the fuel because of the approx 15% loss in charging the battery and is best used for the purpose of maintaining vehicle performance on severe long gradients, a condition seldom encountered in the UK. Regeneration can be utilized to increase battery charge by switching off the hold mode in the longer steep downhill events and during lengthy decelerations and reengaging hold on uphill stretches.
I have used this strategy on vacations. Using the hold mode at 70mph on the motorway is simple, but switching in and out of hold on country roads is more tedious. While it is satisfying to note that on a particular 440 mile journey you have achieved 77.6 battery miles on a single mains charge, it does become a little tedious to flip in and out of hold. I have to be “in the mood” to do this and wonder if the effort is worthwhile in terms of overall cost.
It would be nice to be able to quantify the gains over the GM designed algorithm alone. Increased battery miles will be offset by a reduction in mpg during those periods when the engine is used since the engine will have less light duty and more heavier duty operation per journey. I suspect the difference is small.
I am not measuring individual journey mpg but over 2958 petrol miles so far I have averaged 48.43mpg. and my average full battery distance (assuming 10.7kwh per charge) is 40.10 miles. (since March13 and 8550 total miles). Regrettably battery mileage this last week has dropped to around 29 to 32 so I expect the full year figure to be much lower.

LK13.
 

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Discussion Starter #7
We did a rough test on the a303 this evening. We drove for 10 miles in Mountain mode which gave us about 7 battery miles and used .5 gall fuel. So about 34 mpg. The next 10 miles we used about .2 gall. As I said this was only a rough test and the last part was not on the a303 but it does not seem to be cost effective. We were travelling at 70 mph and the temperature was 4o c.
Geoff
 

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Mountain Mode is very thirsty on the petrol. It will not give you any advantage and as Paul says, you will only get up to 40%.

Some people in the States claim to have hacked the software and removed this limit, but to what end I do not know.
 

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So as a bit of a non scientific test I thought I would try a couple of trials each over 50 miles at a constant speed and see what the mpg would be in hold mode and then mountain mode;

First off was 70mph in hold, average rpm was around 1500, obviously going up or down as I climbed or descended hills, after 50 miles achieved @48mpg.

Next was mountain mode with zero miles on the dash and @20% charge showing on the obd2, after about 15 miles the charge was 42.75% and stablised at that, mpg was a lowly 28mpg. So selected normal and watched the charge deplete back to the minimum 20% (@13miles worth) whereupon the ice cut back in, then continued on to the 50 mile mark and achieved @48mpg.

Hmm, was that right? So did the same again at 75mph (71 true speed)

So 75mph and 50 miles later was doing 45mpg in hold mode, so back into mountain mode, again from zero charge, this time the charge stabilised at 41.96% but took @18miles at @25mpg. Selected normal mode the charge came down to @18.96 ice cut in and continued for the 50miles and got 47mpg.

So what is the conclusion, for me looks like the powertrain engineers put a little mote thought in to mountain mode than I realised, or did they, so will try the same again next week :)

Gary still having fun
32464 miles, mpg down to a poor 90mpg due to several long hauls
 

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It's just a larger buffer. To charge back up to it from belowthe threshold cannot be the most efficient use of petrol the car is capable of. There are moments it's useful if you really must have 10/11 miles range on battery and you missed the moment to set charge hold, but if I have to use petrol I try to use the minimum I can.
 

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(0 charge in beginning) I had nice idea to get some charge to battery (for next morning inner city driving) by using mountain mode for next 10km/6miles and wow, it consumed petrol like never before, about 1.5L and gained 6km/4miles worth of charge..

I imagine there can be narrow chance to get something out of this mode in normal driving by gaining some charge with warm engine and using it in for example next morning in cold weather.. (instead of using cold ICE for short distance when it can get super low mpg..) Better is of course get battery charged but that is not always an option.
 

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Mountain mode was never intended to be used to actually charge the battery from a low state. It is designed to maintain a battery state of charge so that when you are in the mountains you will always have max power available.

Consider it a HOLD mode but at a higher state of charge... about 17 miles range IIRC.

it consumed petrol like never before, about 1.5L and gained 6km/4miles worth of charge..
Well, it is bound to use more petrol... you are running the car AND charging at the same time.

In fact, 1.5l for 6 miles driven and 4 miles stored is about 30mpg.

Mountain mode is great to hold SOC at about 17 miles and great if in the mountains or you want to save your battery power for city use but not much good for anything else IMO.
 

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Hence the name "Mountain Mode" not "Recharge battery mode" :) It's purely designed to be used from the outset or >50% charge level to allow you to support the petrol engine with more battery going up long hills, that's all, nothing else, and for that it works very well.
 

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Some people in the States claim to have hacked the software and removed this limit, but to what end I do not know.
A lack of charging facilities? Expensive electricity? Cheap petrol? All could be valid reasons.

If the price of petrol was as low in Germany as it is in the US, it would be cheaper to charge up the battery using MM, than to charge directly from a charging post, due to the high cost of electricity. There's already little difference between tanking with petrol and charging the battery here but the cost of petrol is far higher than in the US.
 

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If the price of petrol was as low in Germany as it is in the US, it would be cheaper to charge up the battery using MM
But why would you want to? There is never any reason to do that unless you are entering a mountain area and your battery state is low or if you are going to be entering a emissions free zone.

It is a lot more efficient just to run off petrol.
 

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But why would you want to? There is never any reason to do that unless you are entering a mountain area and your battery state is low or if you are going to be entering a emissions free zone.
Well, you've just answered your own question! Not to mention that the car drives beautifully on battery power and like a dog on the ICE :LOL:
 

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Some people in the States claim to have hacked the software and removed this limit, but to what end I do not know.
Because the early Volts did not have Hold mode I suspect.
 

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All Volts in the UK have hold mode.
Yes but my reply was to comment around the States. The UK Volt used the same systems as the Ampera, presumably to simpfiy assembly. The hold mode was added to the USA 2013 model year Volt. 2011 and 2012 model years did not have it.
 
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