[z80]

Okay, I think I'm going to have to do something about this after replying to the Maximum regen rate? thread. So as to not hijack that thread, I'm starting a new one. I think that is the correct thing to do protocol-wise.

Here's the scoop:

I bought a 2013 CPO Volt. This car was only the second Volt that I have ever touched and the first (and only) that I have ever driven so I don't exactly know what to expect. Volts are rare here but I did see one driving in Atlanta last week.

What follows here are pieces of information that I am hoping that someone knowledgeable with Volts might see a common thread and might know of a possible root cause. I'm sorry for it being long but I would hope that a complete summary would be best.

For reference, my other vehicles is a blown 6.2 4WD Silverado. My last car was a recently departed CTS V-Sport (wrecked while parked) which I have not replaced since I didn't drive it much once I got the Volt.

I purchased the Volt to be my daily driver to "save" my Silverado from grunt daily miles. For this, the Volt has been SUPERB! Electric driving is a pleasure and CS mode isn't bad.

The first point is that I think the battery is fine. I get a solid 30 to 40 miles on a charge, assuming good weather and no climate usage, and have seen a period of over 600 miles without any gas usage. My record is like 46 miles on a charge using 10.4 kWh.

I do use the car to drive out of town but am disappointed with CS fuel economy, averaging 24 to 28 MPG on premium gasoline. I did get caught in an area where premium was not available used had one tank of regular unleaded and quoting Mr Ripley, believe it or not, I got 34.x MPG on that tank. Engine seemed to perform fine but I did return to premium fuel and my mileage has since returned to the mid-20's. I could one could add "better MPG with regular than premium" to the wonky evidence.

One interesting point that could be a clue: Highly optimistic fuel consumption reporting. I have begun and ended several out-of-town trips by fueling up at my "favorite pump" with Shell premium, filling in the same manner, and have come to realize that the fuel measured in is considerably more than the car indicates using the Trip B display.

For example, my last trip covering 281 miles two weeks ago, my car indicates that I used 6.5 gallons but Mr Shell sold me 8.3xx gallons. I started with a full charge and recharged at my destination. I recorded on paper that 28.0 + 28.3 miles were on electricity thus leaving 224.7 miles on gas. According to the car, I got 34 MPG or so but calculated 27 MPG according to the pump.

This disappointment is compounded by the net cost being about the same as the pickup. 20 mpg at $2.00 per gallon versus 26 mpg at $2.80 per gallon. But okay, I have just lived with that, wondering about trying another tank of regular unleaded.

Another point is that I just had to put new brake pads on my car. The dealer said the hardware was fine and yet the CPO inspection said the brakes were good. I purchased the car at night after driving to another state and didn't give the brakes a real look over as they felt fine and no pulsation so I cannot confirm that.

The Maximum regen rate? thread really got me thinking. The peak regen I routinely see is -12 to -15 kW while in Low and if braking, no matter how hard, only increases to -17 kW, a number I see frequently while slowing.

Today I realized something else. No matter how hard I press the brake pedal, as soon as the brake lights come on, the MyGreenVolt application will "ding" at me which I believe means the mechanical brakes are engaged. In fact, it is not possible to brake without engaging the hydraulic brakes.

I have been reading more here on the site and see that the peak power output should be over 100 kW. I cannot get it to go over 59 kW power output under any circumstance, Drive or Low, Normal, Sport, Mountain or Hold modes.

I had always thought that Volt performed okay, but I would never say it was "fast." I haven't tried to clock any numbers but remember that other Volt I saw in Atlanta last week? When the light turned green, he left me behind like I was a turtle. The peak numbers seem to confirm that my Volt is slower than other Volts.

Driving up Alabamas modest hills requires full throttle most of the time and accelerating / passing up hill is impossible. Passing on two-lane roads requires lots of room. Back in the 80's, I had a Chrysler K car for a rental that seems to have about the same passing power... they both got around but the sweaty palm detector went off in both cases.

In exactly four months, I've put 6,459 miles on the car, 58.3% EV. How it drives hasn't changed one bit.

There are no check engine lights. I have pulled codes and there is nothing there. Fluid levels look fine. Fluid colors look fine.

My question is if anyone can see something in common with these issues?

The problem is that I can't go into a dealer and say "bad fuel economy" or "poor performance" without something to go on.

On top of that, I don't like the dealer (it's not my regular wonderful non-Volt dealer). For example, when I got the car, the battery coolant level was low and went to buy genuine GM 50-50 to fill and they said that I couldn't do that and quoted $500 to top it off saying it was "sealed for life system" and such. They also quoted $150 to replace the front-right turn signal bulb.

I did the top offs myself anyway without issue, put the Volt on the lift at my good dealer and they let me change the bulb, installed a VoltGrille and VoltPhone mount.

Also the day I got the car, I purchased four Pirelli P7 tires which have performed well, no tire wear, 40 to 41 psi.

Oh, I drove to Tennessee and had a discharged battery in Chattanooga. As left Chatty on IH 24, I remember about the grade up to Monteagle so I engaged Mountain Mode. The engine revved up a bit and I forgot about it until I reached the beginning of the grade, I would say about 45 minutes later.

I was wide open throttle the whole way up doing only 45 mph until Reduced Engine Power came up on the drivers display and dropped to 20 or 25 mph. The battery was fully discharged again; sadly, I did not note the battery level when I started up the grade. Thankfully the Pilot truck stop was in sight where I pulled in, let the car idle in MM for about a half hour while I ate. When I returned to the car, the charge then was only at 3 bars, but it was enough for me to continue my trip.

After the incident, I researched here regarding MM and had bookmarked a couple of threads. One Paging WOT, MM acceleration issue, BAD clearly indicates 80kW when the generator is operating and 110kW in the normal mode, which I fundamentally understand, two motors, one has to generate and such. However I clearly remember going up Monteagle seeing 59kW a number of times. (I see this number A LOT.)

Well, that is all of the information that I can think of. Is there anything else that I can add here?

I do like the car and it suits my needs well. My original idea was that if I liked the Gen 1, I'd later get a Gen 2, even though I have never seen one in person, but I like this car enough, I can see myself driving it for four or five years, assuming the capacitive touch controls and unresponsive touch screen don't drive me crazy. Actually, I wanted the car when it was first shown but since I didn't a local dealer that sold it, I never considered it until recently. And with the prices of the CPO Gen 1's, it was too much of a temptation.

Thanks in advance for any thoughts or ideas that might help me get this car up to speed, no pun intended.

 

[z80]

I wanted to add something about the previous owner and just realized something....

I do know something about the previous owner. For one thing, their address was still in the GPS and Google StreetView shows my car in their garage. It was showing 131 MPG average having run right at 75% of time on the electric power. Interior was immaculate save for a leftover perfume sample between the drivers seat and the console. So, the car was plugged in, garaged and well treated.

The car was in a minor bump showing up on the Carfax. I contacted the dealer that had done the repair only a few weeks earlier. The body shop guy said that "a lady had backed into a post" and that no other damage was done. He said it only required a rear bumper cover, rear reflector and the requisite paint and install. No biggie there but it was a negotiating point and helped me get another $1,000 off!

This is where it gets VERY interesting.... I just calculated this....

Since the car had 39k miles on it, and thus I know that 9,750 miles were on gasoline. OnStar was also able to tell me that the car had consumed a total of 265 gallons of gas.

That equates to 36.792 MPG !!!!!

SOOOO, THIS CAR HAS SEEN BETTER MILEAGE THAN I AM EXPERIENCING!!!

Or is that because the car is reporting less fuel used? Arrgghhh, I don't know!

I would consider fuel quality, but I have purchased fuel in enough places, including ethanol-free premium unleaded at Midnite Oil in Chattanooga at the foot of Signal Mountain.

Okay, thinking cap is getting a working right now...

 

[freshcut]

My biggest question out of all of that is why did you have to have the brakes replaced? It sounds like the brakes are engaged in some fashioned even without any pedal used. Your regen rate should be far higher than your getting. I usually see a max regen rate in the 50kw range when stopping from freeway speeds, and maximum power reaches 114kw when accelerating. This is also on a '13.

Mountain mode should build the battery from a minimum SOC to 50% or so in about 20 minutes. Having had to run yours for 45 should have been more than sufficient to climb any grade. 30 minutes on MM at idle should have had you returning with the 5 bars or so to indicate half of a battery on the GOM, and an engine off since it won't charge more than about 45%.

As for the mismatched pump/trip fuel calculations, I would definitely keep an eye on those. You mentioned it's a CPO, did you also get the onstar set up with a smart phone? If so, I would look at the car status page that shows battery and fuel range. If I recall, the fuel range shows gallons remaining. I have the free basic package so don't remember offhand since I lost that functionality. I would check to see how many gallons it's reporting at fill up, and again at the next fill up and see if it jives with what the car shows.

Sounds like there are a number of issues at play with this vehicle, and with the CPO warranty in effect as well as remaining Voltec/Powertrain I would definitely have it checked out. If nothing else, the very low regen and low acceleration power output are definitely a concern, with the lower power output possibly putting the car into a safety risk since it will have difficulty maneuvering in an emergency situation at this point should you need max power for some reason.

 

[trm2]

Part of the problem is the tires, they are killing the efficiency.

 

[z80]

Thanks for your reply.

My biggest question out of all of that is why did you have to have the brakes replaced? It sounds like the brakes are engaged in some fashioned even without any pedal used. Your regen rate should be far higher than your getting. I usually see a max regen rate in the 50kw range when stopping from freeway speeds, and maximum power reaches 114kw when accelerating. This is also on a '13.

The warning tab was making contact, squealing every time I barely touched the brakes. Surfaces were fine, no pulsation. Just worn pads.

Mountain mode should build the battery from a minimum SOC to 50% or so in about 20 minutes. Having had to run yours for 45 should have been more than sufficient to climb any grade. 30 minutes on MM at idle should have had you returning with the 5 bars or so to indicate half of a battery on the GOM, and an engine off since it won't charge more than about 45%.

If I turn on the car, engage Mountain Mode, and assuming the state of charge is low enough, the engine will come on and the yellow bar will come up to about 1/4 the way up the indicator so it is charging. However at the truck stop the engine was most certainly still running. And I eat very slow... 30 minute is very conservative.

As for the mismatched pump/trip fuel calculations, I would definitely keep an eye on those. You mentioned it's a CPO, did you also get the onstar set up with a smart phone? If so, I would look at the car status page that shows battery and fuel range. If I recall, the fuel range shows gallons remaining. I have the free basic package so don't remember offhand since I lost that functionality. I would check to see how many gallons it's reporting at fill up, and again at the next fill up and see if it jives with what the car shows.

Yes, I have been monitoring the fuel consumption as I realized the discrepancy very quickly. The phone application seems to report the gallons about as accurately as I could expect.

Also the fuel gauge in the instrument display and the low fuel warning seem to be about right. A recent trip to Mississippi, the low fuel light came on and I put something like 8.5 gallons in minutes later.

Sounds like there are a number of issues at play with this vehicle, and with the CPO warranty in effect as well as remaining Voltec/Powertrain I would definitely have it checked out. If nothing else, the very low regen and low acceleration power output are definitely a concern, with the lower power output possibly putting the car into a safety risk since it will have difficulty maneuvering in an emergency situation at this point should you need max power for some reason.

I always need max power (grin).

And, yes, I'm convinced that "something" is wrong, but I would like to approach the dealership with some real evidence. If I were going to my usual dealer, this wouldn't be an issue, but the others, well, you know the rest of that story.

Thanks again!

 

[bentbiker]

How close a match are the new tires to the original? Revs per mile and weight? Certainly, you're paying some penalty in mileage there, but it sounds like a lot more stuff going on.

Have you checked for a dragging emergency brake, or overheated rotors after a drive confirming the friction brakes are working overtime, perhaps dragging?

 

[z80]

Part of the problem is the tires, they are killing the efficiency.

That has certainly been in the back of my mind. That's one reason that I initially dismissed the MPG issues waiting until the tires have some miles on them, but now at least 10% of their usable life has rolled on by and would think that initial mileage losses would have been minimized by now.

Also consider that my EV range is very good, often exceeding the rating. I don't really count highway driving and cold days as they are not optimal for EV operation. In fact, it's going to be cold again over the next few mornings here as we're supposed to get back down into the 50s. (Why did I put up my coats!?)

However on nice days around town, I frequently reach 4 miles per kWh which seems like a good bar to reach.

On top of that, the car seems to roll forever, although just still a bit short of perpetual motion. haha

Actually, if my car really isn't regenerating as much as it should, I wonder how many miles I'm going to get per charge?!

I'm sure in the grand scheme of things there was some loss from maximum / optimal, but I cannot see how they are affecting the other systems or economy while in charge sustaining mode.

Thanks for your reply!

 

[z80]

How close a match are the new tires to the original? Revs per mile and weight? Certainly, you're paying some penalty in mileage there, but it sounds like a lot more stuff going on.

Have you checked for a dragging emergency brake, or overheated rotors after a drive confirming the friction brakes are working overtime, perhaps dragging?

The tires are the same rated size as per the door jam. They were purchased at Sams Club but they won't install tires in sizes that are not on the sticker.

As for revs per mile or weight, I did not compare at the time except for a visual inspection. However I'm checking the web sites right now:

Neither factory web site had full information but Tirerack does:

It seems that the Pirillis are 1 pound heavier and 2/10ths of an inch taller and a bit more contact patch. Close enough for my book, and I am satisfied with their handling and quietness.

As for dragging components, yes, that I one thing that I did check. While I had it on the lift at my regular dealership, I checked for a dragging caliper but couldn't feel anything. I haven't checked using an IR thermometer but honestly, I'm not expecting anything unusual.

Even the dealer when they changed the pads said that the hardware was fine, clean and working correctly. I specifically request the check as I suspected a dragging caliper, as well.

As for the parking brake, I have tested it but frankly, I don't like an electric "emergency" system.

But then again, I'm not suspecting brake drag, especially when my EV range is so good.

Thanks for your reply!

 

[llninja]

The tires are the same rated size as per the door jam. They were purchased at Sams Club but they won't install tires in sizes that are not on the sticker.

As for revs per mile or weight, I did not compare at the time except for a visual inspection. However I'm checking the web sites right now:

Neither factory web site had full information but Tirerack does:

View attachment 134401

It seems that the Pirillis are 1 pound heavier and 2/10ths of an inch taller and a bit more contact patch. Close enough for my book, and I am satisfied with their handling and quietness.

As for dragging components, yes, that I one thing that I did check. While I had it on the lift at my regular dealership, I checked for a dragging caliper but couldn't feel anything. I haven't checked using an IR thermometer but honestly, I'm not expecting anything unusual.

Even the dealer when they changed the pads said that the hardware was fine, clean and working correctly. I specifically request the check as I suspected a dragging caliper, as well.

As for the parking brake, I have tested it but frankly, I don't like an electric "emergency" system.

But then again, I'm not suspecting brake drag, especially when my EV range is so good.

Thanks for your reply!

Sam's club tires. That's the culprit (at least one of them). Give us the the brand and the model name of the tire. My Goodyear assurance tires were great at low rolling resistance, but grippiness was lacking. I switched to Yokohama Ascends and my mileage dropped (i.m lucky to get 30 miles of EV range on a good day) but I also stopped driving like a grandpa and more like Jeff Gordon.

Secondly, I suspect you are driving the car like a jackrabbit, probably at or above the speed limit. That kills range.

best techniques to increase your ev range and gas mileage, slow down, drive like a grandpa, and avoid the brakes or regen as much as possible while being safe. The brake lights will turn on as soon as you press the brake pedal. but that doesn't mean the friction brakes are engaged.

To prove to yourself that a brake isn't dragging, drive for a long stint (3-5 miles at high speed where you don't have to brake much, regen in L until you are almost to a stop, then stop with the brakes. Get out and carefully touch the calipers. If they are all cold, then you are fine, but if one is warmer than another, you have a brake pad dragging.

 

[z80]

Sam's club tires. That's the culprit (at least one of them). Give us the the brand and the model name of the tire. My Goodyear assurance tires were great at low rolling resistance, but grippiness was lacking. I switched to Yokohama Ascends and my mileage dropped (i.m lucky to get 30 miles of EV range on a good day) but I also stopped driving like a grandpa and more like Jeff Gordon.

Secondly, I suspect you are driving the car like a jackrabbit, probably at or above the speed limit. That kills range.

best techniques to increase your ev range and gas mileage, slow down, drive like a grandpa, and avoid the brakes or regen as much as possible while being safe. The brake lights will turn on as soon as you press the brake pedal. but that doesn't mean the friction brakes are engaged.

To prove to yourself that a brake isn't dragging, drive for a long stint (3-5 miles at high speed where you don't have to brake much, regen in L until you are almost to a stop, then stop with the brakes. Get out and carefully touch the calipers. If they are all cold, then you are fine, but if one is warmer than another, you have a brake pad dragging.

Pirelli P7 All Season Tires

And actually, I'm an easy driver. Heck, even my 6.2 Silverado I get 18 to 20 around town. In most vehicles, I exceed EPA numbers nicely. My 2nd to the last car was a 2013 Malibu 2.5 and I'd bust 40 mpg on the highway everyday.

However, yes, I do drive the speed limit or a couple over. Heck, on the way to work, I might even hit 50 MPH.

Seriously, I cannot see that it is my driving habits.

I don't think the brakes are dragging. That car will roll for a long, long time, I have not smelled any hot brakes. Remember, I have had it on a lift for inspection, as well.

A little while ago, since my last post, I decided to hook up MyGreenVolt again and see what it reported. I started this drive with a little over a half state of charge and drove about 28 miles, the last half mile with the range extender kicking in even though I virtually coast that distance.

Also, as before, the moment I touch the brakes, no matter how lightly, DING!

Closer examination reveals some evidence that I can use:

If I am interpreting this correctly, it shows the Max power at 59.4 kW which was full throttle up a hill. (Yes, not eco driving but I was trying to see what this program reported versus what I saw on the main instrument display.)

It also shows Min power at -15.7 kW which would indicate that SOME regeneration did take place.

However look in the lower left corner, 0.1kWhR(0%) which I believe is the number of kilowatt-hours regenerated. Almost nothing.

I'm not sure where the yellow and red segments of the pie chart are coming into play. One is climate control which was set to full off the whole time and the other is the vehicle systems, which included the headlights tonight as well as some wiper use due to light rain.

So, I think the first question to answer is :

Why would a Volt not be regenerating very much ?

 

[z80]

o prove to yourself that a brake isn't dragging, drive for a long stint (3-5 miles at high speed where you don't have to brake much, regen in L until you are almost to a stop, then stop with the brakes. Get out and carefully touch the calipers. If they are all cold, then you are fine, but if one is warmer than another, you have a brake pad dragging.

I just ran (drove) up the street to check something. I just got up to 50 mph and put it into Low. The car began regenerating at -11 kW and kept counting -10, -9, -8, -7 and then straight to 0.5 kW at about 35 mph at which point the car just kept rolling for about a mile and a half until I had to stop for a traffic light. This segment of road had a light decline but not much. I've ridden it on a bicycle and it didn't go downhill enough! haha

Anyhow, I tried a few more times, the car discontinue regen in Low at the slower speeds, but the point is variable at some point between 30 and 40 mph.

I am assuming that it should regen all the way to a stop... Is that correct?

Oh, one more question about Volts.

If I'm in Drive and let off the throttle, a 'normal' car will decelerate using engine braking.

Should a Volt do the same thing?

My car feels like it is coasting in neutral or with the clutch disengaged.

 

[bentbiker]

I am assuming that it should regen all the way to a stop... Is that correct?

It normally transitions from regen to friction brakes at about 5 mph.

 

[z80]

It normally transitions from regen to friction brakes at about 5 mph.

In regular Drive or in Low ?

 

[wordptom]

Oh, I drove to Tennessee and had a discharged battery in Chattanooga. As left Chatty on IH 24, I remember about the grade up to Monteagle so I engaged Mountain Mode. The engine revved up a bit and I forgot about it until I reached the beginning of the grade, I would say about 45 minutes later.

I was wide open throttle the whole way up doing only 45 mph until Reduced Engine Power came up on the drivers display and dropped to 20 or 25 mph. The battery was fully discharged again; sadly, I did not note the battery level when I started up the grade. Thankfully the Pilot truck stop was in sight where I pulled in, let the car idle in MM for about a half hour while I ate. When I returned to the car, the charge then was only at 3 bars, but it was enough for me to continue my trip.

Sounds like your Mountain Mode is not performing as expected. As I mentioned in the other thread, the youtube video Self Charging Volt shows MM recharging a fully depleted 2012 Volt’s 16 kWh battery to the MM-maintained level in 15 minutes using 0.36 gallons of gas while the car is parked. When the MM-maintained soc level is reached, since the car is not moving, the engine shuts off. I’ve experienced this with my 2012 Volt. If you are parked while recharging with MM, when the battery is recharged to the MM-level, the ICE shuts off.

The 2013 battery is slightly larger and might require a few more minutes and use a little more gas, but if you were idling at a truck stop using MM to recharge, and it took longer than ~20 minutes (did you note the amount of Gas Used?), it sounds like there’s something wrong with the MGA generator output or generator-to-battery charging system.

Note, too, that the Gen 1 Volt continues to be propelled by the electric motor in Extended Range mode. Loosely speaking, a Gen 1's gas mileage, i.e., MPGcs, is the distance you can drive on the amount of power provided to the primary traction motor by burning 1 gallon of gas in the generator. If you are generating less electricity per gallon of gas than expected, your gas mileage will suffer. 24-28 mpg is less than expected. Perhaps your generator is not performing as expected.

 

[llninja]

I just ran (drove) up the street to check something. I just got up to 50 mph and put it into Low. The car began regenerating at -11 kW and kept counting -10, -9, -8, -7 and then straight to 0.5 kW at about 35 mph at which point the car just kept rolling for about a mile and a half until I had to stop for a traffic light. This segment of road had a light decline but not much. I've ridden it on a bicycle and it didn't go downhill enough! haha

Anyhow, I tried a few more times, the car discontinue regen in Low at the slower speeds, but the point is variable at some point between 30 and 40 mph.

I am assuming that it should regen all the way to a stop... Is that correct?

Oh, one more question about Volts.

If I'm in Drive and let off the throttle, a 'normal' car will decelerate using engine braking.

Should a Volt do the same thing?

My car feels like it is coasting in neutral or with the clutch disengaged.

Well, what you describe sound like something really wrong with your car. And the dealership doesn't have any ideas? It sound like a volt repair guy needs to look at this drivetrain. Remember the drivetrain warranty is longer than the bumper to bumper. I'd argumtil you are blue in the face that regen is part of the drivetrain.

 

[llninja]

In regular Drive or in Low ?

Both D and L

 

[z80]

The dealership that I prefer and actually do trust (really good people) are not setup to do warranty service on Volts. I drive 40 miles there, right past the local Chevy dealer which, well, let's just say that I get shivers thinking about going there. However I guess I don't have a choice and will stop by tomorrow and make an appointment.

I've already printed the MyGreenVolt screen shot to show essentially no net regeneration.

Any other pieces of information that I should pass on to them past demonstrating the engine "gauge" quitting regeneration ?

 

[freshcut]

Definitely something wrong. in MM, you should see the yellow bar indicating engine operation, usually about 1/3 or so filled, but you should also see green in the regen indicating that it's adding to the battery to build the SOC.

When braking, friction brakes should only be applied when hard braking or speeds below 5mph. This was why I questioned the need for brakes so early. My '13 has over 100K miles and they look almost new. It seems to be that if you needed brakes, its likely been an issue for a while (possibly since new?) that the blended brake system isn't working as designed. I'm curious to add though, when accelerating at max power, what is the yellow bar reading? It should be near or at the max but I suspect you're only seeing it go to about 2/3 or maybe 3/4 since you indicated it's only applying about 60-70kw of power.

In response, you should see regen to about a complete stop when braking. Even light braking should give 10kw of regen with harder braking upwards of 30 to 40+. I probably don't brake as gently as I could, but I still begin to brake within a reasonable distance (4-500 feet from a stop) and even from 45-50 can frequently see regen in the 15+ range when coming down from 50mph or so.

Strictly speaking from my own personal experience, the electric portion of the car should take care of pretty much any driving conditions including braking to such a low speed the mechanical friction brakes are only needed to come to a final stop. It sounds like you definitely need to have a service tech see the car, and if necessary go on a ride along so you can demonstrate these odd behaviors. Definitely something not right!

 

[z80]

Definitely something wrong. in MM, you should see the yellow bar indicating engine operation, usually about 1/3 or so filled, but you should also see green in the regen indicating that it's adding to the battery to build the SOC.

I would say the yellow graph on the right is 1/4 the way up, but I wouldn't argue against 1/3 the way up. As for the green part going down, there is a one pixel slice.

When braking, friction brakes should only be applied when hard braking or speeds below 5mph. This was why I questioned the need for brakes so early. My '13 has over 100K miles and they look almost new. It seems to be that if you needed brakes, its likely been an issue for a while (possibly since new?) that the blended brake system isn't working as designed. I'm curious to add though, when accelerating at max power, what is the yellow bar reading? It should be near or at the max but I suspect you're only seeing it go to about 2/3 or maybe 3/4 since you indicated it's only applying about 60-70kw of power.

At full throttle, it usually goes straight to 59 kW and the left yellow bar going about half-way up.

In response, you should see regen to about a complete stop when braking. Even light braking should give 10kw of regen with harder braking upwards of 30 to 40+. I probably don't brake as gently as I could, but I still begin to brake within a reasonable distance (4-500 feet from a stop) and even from 45-50 can frequently see regen in the 15+ range when coming down from 50mph or so.

If I'm in Low, I see regen up to about -18 kW in the green for a few moments and then it drops to 0.5 kW or 1.0 kW in the yellow.

If I'm in Drive, I see regen up to about -5 kW in the green for a few moments and then it drops to 0.5 kW or 1.0 kW in the yellow.

That's about the simplest way I can describe it. How long it generates depends on the starting speed but I can say that 100% of the time, if I start braking under 25 MPH, I don't see any regen, which I figured was normal since there was less inertia due to the slower speeds.

Strictly speaking from my own personal experience, the electric portion of the car should take care of pretty much any driving conditions including braking to such a low speed the mechanical friction brakes are only needed to come to a final stop. It sounds like you definitely need to have a service tech see the car, and if necessary go on a ride along so you can demonstrate these odd behaviors. Definitely something not right!

I always thought the brakes felt funny is comparison with a regular car, but I figured it was not being used to the technology since I have never driven another Volt. Makes me wonder if I should have driven down to Florida to see one before buying.

Thinking about how to describe the brake feel... I would say for the first 25% of brake pedal travel nothing happens then suddenly it grabs and releases until you reach about 50% brake pedal travel.

 

[freshcut]

I never noticed the brakes felt any different from a regular car. In fact, it's difficult for me to even tell the difference between regen and friction brakes in the Volt. By your description of "nothing for 25% of brake pedal" that tells me that regen is definitely not working right. I notice definite regen at the top of the brake pedal with progressively more regen the more I press. The sudden grabbing indicates the friction brakes are engaging, though not sure on why they release until you hit 50% brake travel other than that would be about where they would normally start to engage under harder braking. I suspect once this is all situated and working properly you will be very pleased with how the brakes work when operating correctly.

I don't really want to speculate anything just yet, but it almost sounds like something in the inverter went wonky but I'd think that should set a SES light. If that's the case, it's definitely covered by the Voltec warranty. I can sympathize with your dealership option. I'm in somewhat the same situation as there is only one Chevy dealership in town with a Volt tech, and my experience with them (as well as others with non Volt vehicles) is less than even mediocre. Unfortunately my next option involves a drive to LA which is about 100 miles south. I guess they know they're the only game in town and use that to their advantage. Definitely keep us posted on what the outcome of this situation is.