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Discussion Starter · #1 ·
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Hello all,

Ive been lurking for a few months, reading up on as much as possible on the Volt. My beloved Audi S6 V10’s crank shaft broke last month, and I swore that would be my last NA car. I know the cost vs. efficiency of the volt would be the best bag for buck for my round trip 94 mile commute.
I found this 2013 67K mile white premier (fully loaded) at the Mannheim auto auction and got it for a good deal.


I have 21 days/200 miles to return the car no questions asked. I wanted to ensure the HV battery unit is in good health. When I picked it up, the battery was empty and running on gas. Lifetime mpg was reported as 85. After a full overnight charge on 120V, the battery reported as “full”, with 32 miles of range. Should this be a red flag for degradation, or soon-to-failure?

My goal is to review the kW consumption on my normal commute tomorrow, to see if it is in the healthy range. The tires on the car are winter, not the LRR units typically equipped.I can’t get the myChevy app to link with my iphone to show more diagnostics on the battery health, unless I misunderstood another thread I’ve read.

Any other tips on car assessment? The hood gasket was not seated to the bumper properly, and the entire engine bay was filthy, with at least 2 spider webs in the compartment. The coolant levels were not completely topped off, situated in the middle of the reservoir markers. Engine oil was at 13%, which is a bit concerning that the previous owner let it get that low. Carfax shows a software update about 20k miles ago, and regular dealership schedules maintenance.

Thanks in advance, looking forward to learning more from this community.

Revolv0
 

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My goal is to review the kW consumption on my normal commute tomorrow, to see if it is in the healthy range. The tires on the car are winter, not the LRR units typically equipped.I can’t get the myChevy app to link with my iphone to show more diagnostics on the battery health, unless I misunderstood another thread I’ve read.

Any other tips on car assessment? The hood gasket was not seated to the bumper properly, and the entire engine bay was filthy, with at least 2 spider webs in the compartment. The coolant levels were not completely topped off, situated in the middle of the reservoir markers. Engine oil was at 13%, which is a bit concerning that the previous owner let it get that low. Carfax shows a software update about 20k miles ago, and regular dealership schedules maintenance.

Thanks in advance, looking forward to learning more from this community.

Revolv0
I just bought a 2013 with 105k about a month ago - also new to the forum, so I can't provide a ton of info, but one of the things that made me feel better about the purchase is that the previous owner stated in the ad that he still got 40 miles to a charge. I have had the same results. I've read on here that the "guess-o-meter" battery-range indicator is very indicative of driving-habits, so I would think it's possible that the 32 miles of range showing could be due to the previous owner. The proof of what it's capable of is obviously only found in what you get after driving it (and how you drive it).

The spider-webs and stuff make me wonder how long the car was sitting, and at what temperatures. Again, not an expert on these cars in the least, but I would think that batteries sitting for an extended period of time not being heated in the winter for example, may cause early degredation? Maybe someone else can provide input?

As for diagnostics, I purchased the android app "MyGreenVolt" and was very happy with the battery health screen, which actually shows you the charge in each of the 90-something cells within the battery. I think it cost $5, but also requires an ODB2 adapter that you plug in under the dash. I just bought this one off amazon, and it works quite well.

I would jack up the rear and and spin the tires too - mine had pads installed backwards on the left, which was causing pretty severe drag, and a couple of seized caliper-pins on the right, also causing some drag. As you may have read on here, the brakes on these cars don't need maintenance due to usage, they degrade due to age.

Good luck and welcome to the club!
David
 

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Discussion Starter · #3 · (Edited)
I just bought a 2013 with 105k about a month ago - also new to the forum, so I can't provide a ton of info, but one of the things that made me feel better about the purchase is that the previous owner stated in the ad that he still got 40 miles to a charge. I have had the same results. I've read on here that the "guess-o-meter" battery-range indicator is very indicative of driving-habits, so I would think it's possible that the 32 miles of range showing could be due to the previous owner. The proof of what it's capable of is obviously only found in what you get after driving it (and how you drive it).

The spider-webs and stuff make me wonder how long the car was sitting, and at what temperatures. Again, not an expert on these cars in the least, but I would think that batteries sitting for an extended period of time not being heated in the winter for example, may cause early degredation? Maybe someone else can provide input?

As for diagnostics, I purchased the android app "MyGreenVolt" and was very happy with the battery health screen, which actually shows you the charge in each of the 90-something cells within the battery. I think it cost $5, but also requires an ODB2 adapter that you plug in under the dash. I just bought this one off amazon, and it works quite well.

I would jack up the rear and and spin the tires too - mine had pads installed backwards on the left, which was causing pretty severe drag, and a couple of seized caliper-pins on the right, also causing some drag. As you may have read on here, the brakes on these cars don't need maintenance due to usage, they degrade due to age.

Good luck and welcome to the club!
David
Thanks David!

My first experience with my community yesterday yield a very pleasant experience. The battery ran for 39.5 miles, and the gas motor used .2 gallons. The car charged on 120v @ 8ah and gave me 20 miles of electric. I used “hold” mode on the freeway, used .6gallons with that partial battery charge. Round trip of 122 gallons is incredible. I think I can charge at work for 12ah OR even 240V. Battery seems to be in good health using 10.2kWH

I ordered the myvolt software you mentioned, and purchased the Bluetooth OBD2+ adapter to further evaluate the battery.

So far, very happy with the efficiency of the car. Driving it makes me safer because I’m no longer speeding. This volt is nearly 10x more fuel efficient that my V10 was!
 

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Usually, the electric Guess-o-Meter reflects how the car is being driven. Take it easy on the go-pedal for a couple of charges and you'll likely see the number increase. If you use the heater or air-con and / or drive it like you stole it and reduce the distance travelled for a few charges, it'll drop. Mine has varied from the low 30s to the high 40s depending on how I drive it and what accessories I use.

Nature of the beast.
 

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Drive it very conservatively (slow starts, speeds under 60, low A/C or heat use) for about 3-4 days, see if the mileage estimate goes up. Also, make sure your tires have 38-40 psi. In addition, drive the cra to full battery depletionand do full recharge 3-4 times to make sure the algorithm hasn't been negatively affected by many small top-offs.
 

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Most definitely blow the tires up to 40. This alone make a large gain vs. the standard “35” most vehicles run. Wind speed and direction can make a big difference as well. Let us know!
 

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Discussion Starter · #7 ·
The test for battery health is to run it dead then monitor cell voltage on MyGreenVolt? What are out of tolerance values?
 

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The test for battery health is to run it dead then monitor cell voltage on MyGreenVolt? What are out of tolerance values?
I was mostly looking for balance among all the cells. The idea is that they should all be within a few millivolts of each other. If they aren't, there isn't anything to be done that I'm aware of but that would (I assume) be the beginnings of a worn out battery pack..

Again, new owner here, still learning about these things. If I'm wrong please someone correct me.
 

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Fully depleted battery - Min to Max difference of 10 -20 mVs what I have observed in the few months I have owned my 2011 Volt. I have seen reported on this forum that a difference of 121mV will trigger an out of balance error code.
MikeB
 

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Fully depleted battery - Min to Max difference of 10 -20 mVs what I have observed in the few months I have owned my 2011 Volt. I have seen reported on this forum that a difference of 121mV will trigger an out of balance error code.
MikeB
At the end of the cell balancing routine (which happens at the end of fully charging the battery), the out-of-balance cannot be more than 121 mV. During operation with a partially charged (or fully charged) battery, instantaneous swings of much greater that 121 mV are ignored.

Noting the cell with the minimum voltage as soon as the car switches from charge depletion to charge sustaining is useful. as well as after cell balancing has taken place after a full charge. Normally, no one cell is constantly at minimum voltage. If one cell is showing up consistently with minimum voltage, that cell may be heading for "disaster". That is my understanding.
 
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More important that what your GOM says, how many kw does your battery deplete from a full charge to empty. My 2013 is between 10.1 and 10.3.

But the GOM is another story. Take today for example. My commute is 27 miles. In the summer, I can run that, and have 13 miles left over. Right now, we have a cold snap at night (21 F last night), and pleasant (60 ish) during the day. So my GOM is all confused. This morning, I departed, with it saying I had 38 miles of range. When I got to work (cold outside), there was 1 mile left, so the guess was 10 miles off. This afternoon (I charged at work), the GOM estimated 32 miles, which was partly based on it's "experience" this morning. After I had driven about 4 miles, it said 34 miles remaining! I got home with 7 miles remaining.

It sounds crazy, but it all makes perfect sense. The GOM starts out with the information it knows, and that includes the morning commute. Then it updates as it gets better (more current) info.

I expect tomorrow morning to see it saying 35-38 miles, and I expect it to just barely make the 27 mile trip (heater running on comfort, seat warmer running as well, lights on, radio on). All is normal.

If you can get 10+ kw run out of a charge, you are looking good.
 

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Discussion Starter · #12 ·
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Battery reported 0 miles, this was the voltage between the packs. Am I good to go to pull the trigger on this car now? Does the battery unit seem in good health with the 10.2 kWH consumption and this tight grouping between battery unit voltages? Thank you all again!
 

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Discussion Starter · #13 ·
As mentioned, I saw some wild jumps during the gas engine ON charging, anything to be concerned with?

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Battery reported 0 miles, this was the voltage between the packs. Am I good to go to pull the trigger on this car now? Does the battery unit seem in good health with the 10.2 kWH consumption and this tight grouping between battery unit voltages? Thank you all again!
GM programmed the Volt to use 65% of the full battery capacity (according to Wikipedia) for Electric Mode driving (electric miles, kWh Used). Extended Range Mode driving (gas miles, gas used) uses the ~5% of full capacity portion between the Electric Mode window and the "hard floor" state of charge level (no user access to the portion of the battery below that).

Your photo shows the mygreenvolt app reporting a "raw" state of charge at 20.0% (bottom of the Electric Mode window, battery depleted). You might want to check that reading when the battery is fully charged, should be ~85% SOC (my 2012 Volt’s window is ~22%-87% SOC, the window can vary with model year).

It’s also helpful, as Steverino mentions above, to take the car through several full charge/full depletion cycles to allow the system to gather calibration data from the full window range . For you, this would also help confirm that the Electric Mode window is remaining fairly consistent in the 20-85% range (65%) for your vehicle, and that the "average" kWh Used per full charge remains close to what you get for each cycle.

And doing so also provides data to obtain a rough estimate of your battery’s current full capacity. If 65% of the full capacity = 10.2 kWh Used, then the current full battery capacity is:
~10.2/0.65 = 15.7 kWh.

A new 2013 Volt was equipped with a 16.5 kWh battery, so this rough estimate would say your current full capacity is 15.7/16.5 = ~95% of the original capacity, or ~5% degradation in ~8 years (battery warranty says "may degrade up to 30% in 8 years/100K miles " and still be within specs).
 

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I realize that you likely do no have your hands on the car currently. When using the MGV app, if you swipe left on the state of charge screen you will see a display of the 96 individual cell voltages. It does not always match the summary screen that you took a shot of, but will be close. (I think the summary may average over a short time period). Here is a shot of mine a few weeks ago. Min to max at full depletion is about 15 mV, which from what I have read is fine. Your first picture shows a lower voltage across the board, with a min to max diff of 7mV. I think you have passed that test from what little I understand about the battery. If you can do it at full charge and look for imbalance issues that would be a good check as well.
MikeB
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I realize that you likely do no have your hands on the car currently. When using the MGV app, if you swipe left on the state of charge screen you will see a display of the 96 individual cell voltages. It does not always match the summary screen that you took a shot of, but will be close. (I think the summary may average over a short time period). Here is a shot of mine a few weeks ago. Min to max at full depletion is about 15 mV, which from what I have read is fine. Your first picture shows a lower voltage across the board, with a min to max diff of 7mV. I think you have passed that test from what little I understand about the battery. If you can do it at full charge and look for imbalance issues that would be a good check as well.
MikeB
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Thanks for the clarification

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Looking at the graph, is Cell 42 dead?
 

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My guess would be that it is not necessarily an issue, likely just did not scan all of the values. Give it a few minutes to settle out on all the resting values. If cell 42 was dead, the app would have reported the value as the minimum. Also the Y-axis in the display would have re-ranged itself to show the value of cell 42. I suspect it did not get read.

edit: also, it looks like in some of your initial screenshots, all of the data did not get scanned. In my app (IPhone), on the summary screen the bar graphs I see are Min, Ave, Max from top to bottom. Some of your screens shots tend to follow this same pattern, while others show a value of 0.014V for the bottom bar. Something does not look right. May be a communication issue? Was the car still turned on and stationary? Wait several minutes for the readings to settle out.
 

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Also, run the same check on the battery just as the charge cycle is finishing. Look for out of balance cells.
 

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I bought a new 2013 VOLT in 2013. Eight years later it charges up to about 38-42 miles in the summer (I live in Seattle, so no too extreme temps) and 32 miles right now, in the fall. In the winter a full charge gets down to about 28 miles, depending on temp. I charge it outside, no garage. My daily commute is only 5 miles. I have 40,000 miles on it. I hope this helps.
 

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I bought a new 2013 VOLT in 2013. Eight years later it charges up to about 38-42 miles in the summer (I live in Seattle, so no too extreme temps) and 32 miles right now, in the fall. In the winter a full charge gets down to about 28 miles, depending on temp. I charge it outside, no garage. My daily commute is only 5 miles. I have 40,000 miles on it. I hope this helps.
Thanks Fisher, my initial assessment of the car is that the battery is fairly healthy. Right off the bat, getting nearly 40 miles on the first full charge on my first commute was pretty good.

After the nightmare of Audi ownership, this can’t be that bad. What I think is low maintenance may be high for some, but I have no concern pulling the trigger on fluid maintenance for the cooling systems, as well as any other scheduled stuff for this car.

Im excited to be a Volt driver!
 
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