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Discussion Starter #1
Hello all,

Had a full charge but depleted it down to 0 miles, got a smog check and it immediately started idling high and the Propulsion Power Reduced came up. Was able to get it home and back on the charger. After a little bit of researching this message, is it true that I should have put it in Mountain mode so it will charge the Hybrid Battery when I get close to 5 miles? I have a Lexus CT200h and it does this automatically.

Please ignore the noobness, just new to this car.

Thanks in advance,
Leo
 

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Mountain Mode is used when you know you will be going up a steep grade (mountains). You engage it about 19 miles (or maybe 10 minutes?) befor starting the climb. Living in flatland, I've never needed it.

Otherwise, the battery may not have quite enough umph to get up the steep grade and it will go into a slow mode climb instead (propulsion power reduced).

Read up on Mountain Mode in your free Owners Manual. It has everything you need to know.
 

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Discussion Starter #3
Mountain Mode is used when you know you will be going up a steep grade (mountains). You engage it about 19 miles (or maybe 10 minutes?) befor starting the climb. Living in flatland, I've never needed it.

Otherwise, the battery may not have quite enough umph to get up the steep grade and it will go into a slow mode climb instead (propulsion power reduced).

Read up on Mountain Mode in your free Owners Manual. It has everything you need to know.
Thanks for that. Yes, same for me, not too many mountains in San Diego, lol. I guess I was wondering why I got into Propulsion Power Reduced when my Hybrid battery at 0 miles? Why doesn't the gas engine take over and charge it without having to move it from "Normal" mode? Is the switch to "Mountain" mode to charge just some misguided post?
 
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Mountain Mode is the only mode that will charge your battery (not counting regen) but it is not an efficient battery charger compared to plug in charging. It's there to ensure you have up to 40% of battery to aid you over steep mountain sections on longer drives (it recharges on flat or downhill sections to build battery up from next uphill section). To do this it will rev at higher rpm's, making more noise and more vibration sucking up more gas (compared to other modes, that's the trade off).

Once battery depletes in Normal Mode it should turn on the ICE to produce the electricity to drive the electric motors (ignoring the computer direct connecting the ICE when it's more efficient to do that). This should be pretty transparent with only a slight vibration in steering wheel for feed back (engine noise should be mostly covered by tire road noise at speed). This depletion should be done occasionally/periodically to deplete the battery so the charge range doesn't close in (gradual as it may be).


Unfortunately you don't have Hold Mode (came in 2013) were when you are on intercity trips you can use battery in town (more efficient) and hold the battery to use ICE on highway (it's most efficient) then switch back to battery when you hit the next city. I use this all the time and was one of the requirements in my looking for a Volt.


Others can check me (as I haven't been there yet) but you shouldn't have any Propulsion Reduced coming up when it turns on the ICE at battery depletion. Sounds like you have a problem there.
 

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The "smog check" indicator tells me the ICE engine didn't start properly. The Propulsion Reduced is normal when the car tries to start the ICE engine and can't. I suspect a trip to the dealership may be in order.
 

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Discussion Starter #6
The "smog check" indicator tells me the ICE engine didn't start properly. The Propulsion Reduced is normal when the car tries to start the ICE engine and can't. I suspect a trip to the dealership may be in order.
There wasn't a smog check light of any sort. I just went to get a biennial smog check since it is required by law in Calif.
 

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Mountain Mode is the only mode that will charge your battery (not counting regen) but it is not an efficient battery charger compared to plug in charging. It's there to ensure you have up to 40% of battery to aid you over steep mountain sections on longer drives (it recharges on flat or downhill sections to build battery up from next uphill section). To do this it will rev at higher rpm's, making more noise and more vibration sucking up more gas (compared to other modes, that's the trade off).

Once battery depletes in Normal Mode it should turn on the ICE to produce the electricity to drive the electric motors (ignoring the computer direct connecting the ICE when it's more efficient to do that). This should be pretty transparent with only a slight vibration in steering wheel for feed back (engine noise should be mostly covered by tire road noise at speed). This depletion should be done occasionally/periodically to deplete the battery so the charge range doesn't close in (gradual as it may be).


Unfortunately you don't have Hold Mode (came in 2013) were when you are on intercity trips you can use battery in town (more efficient) and hold the battery to use ICE on highway (it's most efficient) then switch back to battery when you hit the next city. I use this all the time and was one of the requirements in my looking for a Volt.


Others can check me (as I haven't been there yet) but you shouldn't have any Propulsion Reduced coming up when it turns on the ICE at battery depletion. Sounds like you have a problem there.
Really great info but can you define ICE so I can follow the reply. Again, a noob posting here.
 

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I had that happen once on my wife’s Volt after a section of the battery was replaced. I think the car hadn’t really balanced the cells yet. Otherwise it’s been fine. You may find that yours is fine now too, and it was just a one-off occurrence if it previously didn’t get the battery to empty much.
 

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Hello all,

Had a full charge but depleted it down to 0 miles, got a smog check and it immediately started idling high and the Propulsion Power Reduced came up. Was able to get it home and back on the charger. After a little bit of researching this message, is it true that I should have put it in Mountain mode so it will charge the Hybrid Battery when I get close to 5 miles? I have a Lexus CT200h and it does this automatically.

Please ignore the noobness, just new to this car.

Thanks in advance,
Leo
I have a 2011 as well (plus a 2016).

You probably want to check out this thread too.

http://gm-volt.com/forum/showthread...ge2&highlight=battery+degradation+wear+normal

It could be 'normal wear' (GM terms for battery degradation). See below.

 

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It could be, of course, the Propulsion Reduced episode is letting you know your 2011 Volt is experiencing normal aging issues...

If you continue to get Propulsion Reduced episodes under normal driving conditions, try using Mountain Mode as a temporary fix to see if it eliminates the Propulsion Reduced episodes. Switch to MM as you head out for the day, and any time you stop, and then start out again.

In a 2011/2012 Volt, when you switch into MM with sufficient charge still in the battery, the ev range estimate will immediately decrease by ~14 miles, but from that point on, everything will operate as it normally would, and when the revised ev range drops to 0, the car will switch to gas operations.

By increasing the size of the buffer via MM, the amount of power maintained in the battery buffer that is available to be borrowed if needed to maintain performance when the engine is running is increased. This might be enough to prevent Propulsion Reduced episodes.

If the episodes continue, here’s what is happening. To maintain battery life, GM has limited the driver to using only ~65% of the full capacity of the 2011-2015 Volt’s battery. A "fully charged" battery’s state of charge (SOC) is ~85%/87%, and the "switch to gas, fully depleted" SOC is ~20%/22%. Some say under normal driving conditions, the switch is made when the SOC drops to 20%, and then the generator recharges it up back up to a minimum maintained 22%. There’s also a "hard floor" to the SOC level - let’s say around 15% SOC - below which the car’s engineering would not let the battery go.

When the battery is depleted, the motor, in effect, uses the generator output instead of the battery as the electric fuel source. Sometimes the power demand request cannot be met by generator output (e.g., you step hard on the accelerator to pass someone), so the motor "borrows" some extra electricity from the battery... when demand lessens, generator output replaces it...

In the Gen 1 Volts, "borrowing" is done from this ~5% buffer of potentially usable power (~0.8 kWh in the 2011/2012 Volt) below the SOC level being maintained by the generator as you drive and the "hard floor" SOC level.

If the motor attempts to borrow an amount of electricity that would bring the battery SOC too close to the "hard floor" SOC, the computer instead puts the car into Reduced Propulsion Mode that requires less power. The ICE starts revving higher to generate electricity to recharge the battery and increase the SOC back up to the maintained minimum level.

For all Gen 1 Volt models, power demands greater than the remaining battery buffer in the normal fully depleted battery can handle and still maintain performance may occur in certain driving conditions (such as when trying to pass while driving fast up a steep mountain road). "Mountain Mode" was created for when such conditions are anticipated... selecting MM increases the normal "minimum" SOC level (wikipedia says to 45% for the 2012 Volt), increasing the amount of battery power preserved as a buffer for use in these conditions so that your Gen 1 Volt can maintain performance under those conditions.

As the Gen 1 Volt ages, something may impact the "full capacity" of your battery. It may generally degrade, or some cells may have problems, and full capacity decreases. Just as the quantity of power in that 65% usable window of power would shrink as the full capacity shrinks, so would the ~0.8 kWh of power in that 5% buffer between "switch to ICE" and the hard floor SOC. The full output capacity of the gas-engine generator may remain as before, but there’s a smaller amount of power in the battery buffer to use for those "extra power" demand requests.

Thus an aging Gen 1 Volt might have a smaller "borrowable" battery buffer when using the range extender, and therefore might endure "Propulsion Reduced" episodes even when you’re not driving in the mountains, simply because the vehicle is getting older. Unfortunately, the warrantee language for Gen 1 Volts suggests up to a 30% degradation in the warrantee period is likely to be within specs, and that’s certainly enough to produce occasional Propulsion Reduced messages.

As Moderator scottf200 points out above, this could be normal aging. Of course, other types of battery problems could also cause Propulsion Reduced episodes. Your service department can advise.
 
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