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Discussion Starter #1
My early impression--subject to revision--is that my Gen 2 does a worse job "holding" EV miles than my Gen 1 using it on the same commute.

I can't figure out if Gen 2 tries to "get back" to the held SOC setpoint, especially if it requires battery power beyond the ICE alone. On my Gen 1, the ICE (mostly) added charge to maintain the HOLD setpoint--but it also operated in a serial hybrid capacity. On my Gen 2, it seems that whenever it needs battery + ICE (like hard acceleration), it doesn't try to "replace" it. Maybe a characteristic of the parallel hybrid setup? Or maybe it tolerates more deviation?

It seems this member also noticed this issue on a 2000-mile trip where he used "hold" the whole time and lost half his EV miles. http://gm-volt.com/forum/showthread.php?284690-Questions-about-Hold-mode

What's going on here? Is the battery just augmenting the ICE in Hold mode? Do I need to drive within the (lower) power demands of the ICE alone in hold to avoid drain? Under what conditions (if any) will Gen 2 maintain the Hold setpoint?
 

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My early impression--subject to revision--is that my Gen 2 does a worse job "holding" EV miles than my Gen 1 using it on the same commute.

I can't figure out if Gen 2 tries to "get back" to the held SOC setpoint, especially if it requires battery power beyond the ICE alone. On my Gen 1, the ICE (mostly) added charge to maintain the HOLD setpoint--but it also operated in a serial hybrid capacity. On my Gen 2, it seems that whenever it needs battery + ICE (like hard acceleration), it doesn't try to "replace" it. Maybe a characteristic of the parallel hybrid setup? Or maybe it tolerates more deviation?

It seems this member also noticed this issue on a 2000-mile trip where he used "hold" the whole time and lost half his EV miles. http://gm-volt.com/forum/showthread.php?284690-Questions-about-Hold-mode

What's going on here? Is the battery just augmenting the ICE in Hold mode? Do I need to drive within the (lower) power demands of the ICE alone in hold to avoid drain? Under what conditions (if any) will Gen 2 maintain the Hold setpoint?
I've never noticed mine losing miles in Hold mode. Whenever I use Hold, it will run the engine at a high idle when I'm coasting or close-to-coasting and the battery power gauge on the left goes down into the green while it returns to the setpoint. This only occurs after heavy acceleration. I've driven over a hundred miles in one Hold trip before and never lost a single mile of EV range.

Now, if you're driving up a steep slope such as a mountain the whole time, it's not going to have time to recover the lost mileage unless you drive flat or downhill for a while in the same trip afterwards. Note that the setpoint gets reset to the current SOC any time the vehicle enters Hold mode.
 

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Discussion Starter #3
Whenever I use Hold, it will run the engine at a high idle when I'm coasting or close-to-coasting and the battery power gauge on the left goes down into the green while it returns to the setpoint.
Thanks -- so yours is one scenario when Gen 2 seems to provide some ICE-assisted battery charging. Maybe in my early use I haven't hit those yet.

I've lost a couple miles in hold and haven't ever seen the "green" show up on the battery except from some opportunistic regen (I use classic enhanced). I tried one trip in HOLD in Modern Enhanced view and only ever saw yellow on the left battery side, but of course I wasn't staring at it the whole time, still lost a couple miles.

I would think there has to be an algorithm in Gen 2 that actively works to "maintain" the HOLD setpoint. I knew those times in my Gen 1 but they seem different in the Gen 2.
 

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I have noticed that I may lose 1 (2 at most) miles of EV range while in hold mode if I am going up a relatively steep incline. I have also seen the scenario where the ICE will run a high RPM to recharge the battery buffer (kW used in the negative/green area).
 

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No question the G2 in Hold mode will use battery whenever it needs it for hill climbing, or acceleration. Eventually the engine will attempt to replace some of that, but there don't seem to be any guarantees about how much will get replaced. If you are low on charge and need more of it for later, I suggest MM instead of hold to put some juice back in the battery. Otherwise in Hold mode you are susceptible to losing some.
 

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I hate to sound like a broken record bringing this up so often, but using the ICE to add juice to the battery is horrible for efficiency; especially if the ICE is also moving the car at highway speeds. If you need the battery buffer because you are driving in the mountains, then that's fine ... and that's what Mountain mode is for. Otherwise I'm happy to trade electrons to keep the ICE operating at an efficient RPM/load range.

Obviously it's helpful to discuss differences between how the Gen 1 and Gen 2 operate under Hold mode and how the Gen 2 is less emphatic in keeping the SOC at a particular point so folks can manage their SOC for their desired outcome, but for almost any situation that I can think of, it's an improvement for the Gen 2 to be more aggressive in dipping into the battery while in Hold mode and an improvement that the Gen 2 waits for favorable conditions (deceleration, downhill, etc) to replace that charge.

Stray observation ... if the ICE is cold, you will always loose a couple of miles of electric range when you first engage Hold at highway speeds. That's because the car is limiting the ICE output during warmup.
 

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It does take a little while for the 2016-17 gas engine to heat up to full operating temp but the engine does see to add the extra mile or two to the electric range that was used when hold mode was engaged.

With our 2016 Volt we always use hold mode when we have extended trips to Portland Oregon as it sure is nice to have 20 miles or so of electric range at your finger when you are stuck in heavy traffic, or city driving.
 

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I hate to sound like a broken record bringing this up so often, but using the ICE to add juice to the battery is horrible for efficiency; especially if the ICE is also moving the car at highway speeds. If you need the battery buffer because you are driving in the mountains, then that's fine ... and that's what Mountain mode is for. Otherwise I'm happy to trade electrons to keep the ICE operating at an efficient RPM/load range.

Obviously it's helpful to discuss differences between how the Gen 1 and Gen 2 operate under Hold mode and how the Gen 2 is less emphatic in keeping the SOC at a particular point so folks can manage their SOC for their desired outcome, but for almost any situation that I can think of, it's an improvement for the Gen 2 to be more aggressive in dipping into the battery while in Hold mode and an improvement that the Gen 2 waits for favorable conditions (deceleration, downhill, etc) to replace that charge.
No doubt that the implementation in G2 is an improvement. The bottom line is that the car needs it's battery under just about all circumstances. The concept of Mountain Mode is really a misnomer and designed to get someone thinking about this in the appropriate way. But the best way to drive the car is in Hold mode with a good deal of battery available for when it's needed (mountains or otherwise). If you are running low on battery, MM is there to help build it up -- since you need it all the time.

Reference the backfire issue in Hold mode when you have no battery left, it wouldn't surprise me if the engineers knew about this all along. The car can optionally run on engine, but it MUST have battery available all the time. If you are going on a long trip, be it to the mountains or the beach, you need to keep some battery in reserve. And if you run low, kick it into MM.

This highlights another point I've supported: that this car is not designed to be driven blindly.
 

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No doubt that the implementation in G2 is an improvement. The bottom line is that the car needs it's battery under just about all circumstances. The concept of Mountain Mode is really a misnomer and designed to get someone thinking about this in the appropriate way. But the best way to drive the car is in Hold mode with a good deal of battery available for when it's needed (mountains or otherwise). If you are running low on battery, MM is there to help build it up -- since you need it all the time.

Reference the backfire issue in Hold mode when you have no battery left, it wouldn't surprise me if the engineers knew about this all along. The car can optionally run on engine, but it MUST have battery available all the time. If you are going on a long trip, be it to the mountains or the beach, you need to keep some battery in reserve. And if you run low, kick it into MM.

This highlights another point I've supported: that this car is not designed to be driven blindly.
If you put your energy display on with the car/engine/battery graphic you can monitor easier just what's going on all the time...there are times while in Hold, MM, or even a fully depleted battery, where there is some electric use, combined electric and gas, and sometimes just gas, as well as gas powering the drive train and charging. I've had no issues with my '17 losing charge in hold mode, unless maybe you take the reading right after climbing a long hill.
 

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Driving in the mountains in Western Maryland on "Hold" I noticed the battery range would drop a mile or two for a bit, but it recovered fairly quickly.
 

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It's an amazing car and for me, playing with the "system" to try and maximize EV miles is a great way to pass the time on longer trips. I always use "L" and I always try to arrive back home with as close to 1 or 2 EV miles left. The Volt is like a "teaser" vehicle for folks that aren't sure about a pure BEV. Once you experience electric only driving you really can't wait to get a pure BEV.
 

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It's an amazing car and for me, playing with the "system" to try and maximize EV miles is a great way to pass the time on longer trips. I always use "L" and I always try to arrive back home with as close to 1 or 2 EV miles left. The Volt is like a "teaser" vehicle for folks that aren't sure about a pure BEV. Once you experience electric only driving you really can't wait to get a pure BEV.
No disagreement there. That's why this car is not for the average clueless driver. Also, if you are a one car family, the Volt still makes sense over a pure BEV.
 

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That's why this car is not for the average clueless driver. Also, if you are a one car family, the Volt still makes sense over a pure BEV.
Works just the same for the average clueless driver. If you don't care about stuff, the only difference is "plug it in when you get home", and that's it. And the clueless will still get like 95% of the efficiency, performance, etc. that someone that obsesses about every detail of tire pressure and Hold Mode timing and when to use L instead, just by driving it as though it were any other car. The improvements available from fussing over things are so small, they barely matter. Even getting five miles of extra EV range amounts to, over the course of a commuting year, about fifty bucks in gas, if and only if you're already commuting enough to actually use up the whole range. Which most people aren't.
 

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Works just the same for the average clueless driver. If you don't care about stuff, the only difference is "plug it in when you get home", and that's it. And the clueless will still get like 95% of the efficiency, performance, etc. that someone that obsesses about every detail of tire pressure and Hold Mode timing and when to use L instead, just by driving it as though it were any other car. The improvements available from fussing over things are so small, they barely matter. Even getting five miles of extra EV range amounts to, over the course of a commuting year, about fifty bucks in gas, if and only if you're already commuting enough to actually use up the whole range. Which most people aren't.
You have a point. The average clueless driver would barely notice the constant backfires anyway :)
 

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No doubt that the implementation in G2 is an improvement. The bottom line is that the car needs it's battery under just about all circumstances. The concept of Mountain Mode is really a misnomer and designed to get someone thinking about this in the appropriate way. But the best way to drive the car is in Hold mode with a good deal of battery available for when it's needed (mountains or otherwise). If you are running low on battery, MM is there to help build it up -- since you need it all the time.

Reference the backfire issue in Hold mode when you have no battery left, it wouldn't surprise me if the engineers knew about this all along. The car can optionally run on engine, but it MUST have battery available all the time. If you are going on a long trip, be it to the mountains or the beach, you need to keep some battery in reserve. And if you run low, kick it into MM.

This highlights another point I've supported: that this car is not designed to be driven blindly.
I don't really agree with this. I'm guessing you probably have a Gen 1; the Gen 2 is designed differently and can really be driven as a normal hybrid without ever being plugged in or paying attention to the battery at all. Of course, why not charge it when you can? But in the Gen 2, the ICE should have plenty of power for climbing a mountain even with the EV range completely depleted. The engine is just as powerful as a Prius, and a Prius doesn't have any concept of mountain mode or anything.
 

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I don't really agree with this. I'm guessing you probably have a Gen 1; the Gen 2 is designed differently and can really be driven as a normal hybrid without ever being plugged in or paying attention to the battery at all. Of course, why not charge it when you can? But in the Gen 2, the ICE should have plenty of power for climbing a mountain even with the EV range completely depleted. The engine is just as powerful as a Prius, and a Prius doesn't have any concept of mountain mode or anything.
I mostly agree with you and hellsop w/r/t the notion that the car can be driven Ronco mode (set it and forget it), but there are significant gas milage improvements attainable on long trips if you are inclined to manage the SOC. I'm not one of those holier-than-though hypermilers and I only check voltstats about once each month. If you are in a Volt, you are ahead of 99% of other drivers in terms of efficiency even if you never touch the mode button. But if you are inclined to maximize your efficiency because you enjoy geeking out on such things, then these discussions are of value.

RE: the comparison to the Prius, keep in mind that the Volt weighs 500 lbs more due in large part to the heavy battery pack. I'm not sure the Volt can perform as well as the Prius on a depleted pack in the mountains.
 

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I don't really agree with this. I'm guessing you probably have a Gen 1; the Gen 2 is designed differently and can really be driven as a normal hybrid without ever being plugged in or paying attention to the battery at all. Of course, why not charge it when you can? But in the Gen 2, the ICE should have plenty of power for climbing a mountain even with the EV range completely depleted. The engine is just as powerful as a Prius, and a Prius doesn't have any concept of mountain mode or anything.
I actually have a G2 ;) And while I enjoy my car immensely, between my own experiences and what I read on this forum, I appreciate the car's limitations. And I firmly believe that those limitations are represented in the delta between Prius sales and Volt sales. Chevy's plan was to build a capable electric car with additional range. Toyota just wanted to sell lots of cars to their known demographic of clueless drivers looking for reliable (and efficient) transportation. Much as it wouldn't be my choice, going forward I suspect we may see more and more cars in the Prius/hybrid mold, whereas the Voltec may ultimately disappear.
 

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Discussion Starter #19
Would be great to know when Gen 2 "decides" to recharge a little. In Gen 1 it happened more often because most modes operated as a serial hybrid. Heck, if you drove under 62 MPH on a flat surface it would just cycle gas/electric, which I always thought was interesting.

I read through the summaries of the 3 "extended range modes" of the Gen 2 Volt and couldn't figure out when/if it would "recharge." Might need to do a deeper dive.

After a 90 mile drive today in 45-55 MPH roads, I did notice what seemed a little "cycling" in Gen 2 around 45 MPH, but the terrain was too hilly to make any firm conclusions. What I've observed so far on gas in Gen 2 is the following:

0-25 MPH mostly battery
25-45 MPH Gas or Battery
45 MPH + Gas only, with battery assist
I also noticed that the ICE shuts off quickly upon heavy regen/hard deceleration.

My working assumption is that the more powerful ICE + parallel hybrid allows for more SOC drift in extended range mode because the battery is less essential for many power demands, unlike Gen 1.
 
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