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Discussion Starter #1 (Edited)
I started some discutions but nobody answer this simple question. I get the SHVCS message 2 weeks ago and the only solution offered by my dealer service was to update the battery module software and another one. I don't get more than 9.3kwh maximum and as low as 8.9kwh, did your kwh used were changed?
I need answers from people who made this update
 

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I believe that to get the software to maximize the battery range, you have to fully deplete the battery and have the on-board generator start up. And, this has to be done 10 - 12 times. That was my experience. Good luck.
 

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Discussion Starter #3
I do fully deplete the battery until ICE kicks in and I done 6 cycles till now but my range actually is worst with every cycle, from 62km right after the update to 52km yesterday and 8.9kwh used. How many usable kwh and range do you get now on fully charged battery and what you get before this update? What year was your car manufactured and when you get this software update done?
Thanks
 

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The Chevy Volt Owners Facebook group has one participant who is a Volt tech. Here are three of his postings that speak to the need to recalibrate your car’s range estimate programming by carrying out a number of full charge/full discharge cycles.

Note especially the second item, where he recommends up to a dozen cycles AND that it helps accelerate the learning process by waiting two hours before plugging in to recharge and leaving it plugged in for two hours after it reaches full charge.

The third item suggests that the update will create a default setpoint that is only ~10% above maximum allowable degradation, and that it takes a number of full cycles to adjust it from there (which could mean the more full cycles of charged/depleted you do, the more data the system can collect to calibrate the Battery State Estimate Algorithm that helps determine when the "fully charged" SOC has been reached and when the "switch to gas" SOC has been reached.


Jaryd Carvell->Hi friendly neighborhood Volt tech here! As I have tried to explain to so many people in this group. The recall (GM Program #:N172130462 Issued:Mar 28, 2019) is to correct your vehicle from improperly balancing the cells over time. The balance of those cells is part of what is used to calculate the GOM. When they reprogram the module 2 things happen. The vehicle starts to properly balancing the cells again, and the battery capacity learned values are reset. Over the course of multiple charge/discharge cycles the cells properly balance, and then the module relearns the capacity and the GOM adjusts accordingly. If your GOM goes up or down it means that the car had not been properly balancing the cells for quite some time. This process happens much slower without full discharge/charge cycles and so some people the adjustments happen much quicker than others. Also not all vehicles have the same cell imbalance. Even with the bad software some vehicles were staying close to properly balanced and others were quite a bit off. If yours was one that was close to correct, not much will change after the recall. If your cell balance was off, the more it's going to change after the recall. This is why some people noticed almost no change and others have had a change in the GOM. This is also why some people have seen the change quickly and some it took a while. Complete discharge/complete charge cycles will accelerate this learning process. Oh and one more thing, the 2013-2015 volts have 9 battery temp sensors but really only need 6. There is also software included in the recall that allows the vehicle to ignore up to 3 of the redundant temp sensors if they fail, rather than having to replace them. So there are multiple reasons to have this recall performed.


Jaryd Carvell Hi friendly neighborhood volt tech here! The recall has absolutely nothing to do with the "reduced propulsion power" message. If they did the relearn procedure, as Mike Thompson said, it can be up to a dozen full discharge/charge cycles. It also helps if you leave it discharged for 2 full hours before plugging it in, and once fully charged leave it plugged in for 2 more full hours. This will accelerate the learning process.


Jaryd Carvell Hi friendly neighborhood volt tech here! Yes it's totally normal. The relearn procedures at the dealer are only the initial learning and the default learned setpoint is only like 10% above maximum allowable degradation. It will continue to adjust with each full discharge/charge cycle.



If it is any reassurance, a thread was posted about one month ago by someone who had a new battery installed into their 2013 Volt and was having low kWh Used / low full charge range issues, plus rapid change of range estimates, etc. And then the OP posted...

"Looks like problem solved itself. It seems the car needed a few cycles to calibrate the new battery. I got to work with 8 miles to spare and restarting didn't gain any battery.
Plus side is I never had this much range left coming to work so seems like the battery is a huge upgrade."

Perhaps there is hope, and your desired kWh Used / ev range will return after just one more full charge/full depletion cycle... or two more... or three more...


For more information on the Battery State Estimate Algorithm and the kWh Used display, check out forum moderator Steverino’s kWh Used vs. Battery Degradation FAQ:
 

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Discussion Starter #5
Thanks 'wordptom", I read all the above and follow the recomandations of waiting 2 hr before and after charge, but my range loss is 20km, I did't read anywhere about someone that has drop of 15-20 km and a full 1kwh of usable battery and then recover after these procedures...
 

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Thanks 'wordptom", I read all the above and follow the recomandations of waiting 2 hr before and after charge, but my range loss is 20km, I did't read anywhere about someone that has drop of 15-20 km and a full 1kwh of usable battery and then recover after these procedures...
Continue with the complete cycling of the battery for an additional 6 charging cycles and then make a determination. BTW, my footer in my posts shows that I own a 2014. My software update was performed by the dealer on June 12, 2019.
 
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Discussion Starter #7 (Edited)
Thanks again, I'll wait to finish about 12 cycles and see after if it gets better. I guess everyone is so happy to regain old range that they forget to write back on the forum :). On 2014 how many used kwh did you get now? You got the 16.5kwh battery si I guess you should be getting around 10.5kwh.
I've got 40.9Ah available battery capacity on myvoltcapacity, so about 15kwh available battery and I supose to get 9.7used kwh. I understand that GOM is not an exactly accurate, but before the update I get most of the time 9.7kwh - 9.8kwh minimum.
 

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After the update I was limited to 9.7 kWh. The range has increased to 10.4 kWh. The odometer is currently at 123,421 miles with 90,878 miles powered by the on-board generator. I travel a lot and don't plug in while I am on my trips. My lifetime averages are 4.4 miles per kWh and 41.5 miles per gallon gasoline. I limit myself to 65 mph on my trips (though I will speed up to 70 - 80 mph to not block traffic when I need to). I don't want to beat up my Volt with high-speed driving as I want it to be my last car.
 

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Discussion Starter #9 (Edited)
After the update I was limited to 9.7 kWh. The range has increased to 10.4 kWh. The odometer is currently at 123,421 miles with 90,878 miles powered by the on-board generator. I travel a lot and don't plug in while I am on my trips. My lifetime averages are 4.4 miles per kWh and 41.5 miles per gallon gasoline. I limit myself to 65 mph on my trips (though I will speed up to 70 - 80 mph to not block traffic when I need to). I don't want to beat up my Volt with high-speed driving as I want it to be my last car.
Now, that is good news ("After the update I was limited to 9.7 kWh. The range has increased to 10.4 kWh")
I got my Lifetime 2.7 L/100km (87mpg) on 56k miles. I drive 90% in city but with alot of short stops that affect my range. on the freeway I drive with 130km/h (80miles), but only use EV mode in city, on the freeway on that speed is not worth it.
I onso average 7km/kwh but as I mention, if I drive 7km with one kwh and stop for five minutes then go, with the next kwh I drive like 4-5km max. I guess GOM doesn't have time to estimate, that is why for better callibration is better to leave it 2hr before plugging in. Long stops doesn't affect my range, but I noticed that my AC working harder and consume more than before the update. Maybe is just autosuggestion but is sees louder and eats alot of juice.(When I got SHVCS essage,one error code was for low AC cooling agent, that was refilled)
P.S How do you know exactly how many miles you drive on EV and how much on ICE? Using a OBD I guess...
I have 40.9Ah(about 14.7kwh) available battery, from 45Ah when the car was new.
 

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I onso average 7km/kwh but as I mention, if I drive 7km with one kwh and stop for five minutes then go, with the next kwh I drive like 4-5km max. I guess GOM doesn't have time to estimate, that is why for better callibration is better to leave it 2hr before plugging in. Long stops doesn't affect my range, but I noticed that my AC working harder and consume more than before the update. Maybe is just autosuggestion but is sees louder and eats alot of juice.(When I got SHVCS essage,one error code was for low AC cooling agent, that was refilled)
Cabin climate recovery is a factor. Even in only 5 minutes. Fans turn off and stop cooling things, so heat starts pooling.
 

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After the firmware update was done to my 2014, the reported used capacity has dropped from around 10.4kWh to around 9.5kWh. It's been about 10 months, a bunch of full discharge in that time. I think there is permanent degradation of the battery pack, I'd have expected re-calibrate to have occurred by now.

In retrospect, after 6 years, it's foolish to think there would be no noticeable battery capacity loss. Meaning that seeing none reported by the car after this time should have been telling me something. We'd read on this forum rationalizations that the GM did this by gradually reducing the unused capacity at the bottom and top end ( bottom ~20% and top ~ 20%) but this was really a guess - none of us knew if this was really true, it just seemed to fit the situation.

A FW bug that breaks or disables cell balancing is a very large whoops - it's hard to see how this wasn't detected for so long. It's so large an oversight I kinda wonder if it's really true, and especially wonder what the rest of the story is.

I'd hoped my car would gain back some battery capacity, but instead I'm finding that it can be even lower the the typical 9.4kwh these days. When it's cooler weather, it seems especially prone to engaging the gas engine early versus letting you get those last bit of 'fumes' out of the battery.

Lumos
2014 Gen 1 ~ 58kmiles
 

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Discussion Starter #12
Something I nottice today after fully discharge the battery at 9.3kwh and 63km was that after I put it to charge it show estimate time of 8hr15min to fully charge instead of 8hr45min or 9 hours that supose to, as it did in the last 5 years. About 45min is exactly how long it takes to charge ~1kwh.
 

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A comment posted in another thread reminded me that there are at least three original conditions that might result in the Gen 1 Volt problem of "lost kWh Used / lost ev range."

The problem may have begun with the "Service High Voltage System" message. Or, older Gen 1 Volts are subject to a couple of related problems. One is the cell-balancing problem, and the other is simple loss of capacity from growing older. These are separate issues with separate treatments. The PPR problems arising from a simple loss of "oomph" are the subject of Bulletin No. PIC6292C, whereas GM program #N172130462 (and N172130461 for 2011 Volts) refers to the procedure whereby the Chevrolet dealer updates the Hybrid Powertrain Control Module (HPCM2) to prevent the gradual loss of the Volt’s ability to maintain voltage (the cell balancing issue).

The comment that brought this to mind was one that mentioned the PPR problem... the solution to that particular problem, apparently, was to program an increase in the size of the battery buffer the car uses when running on the generator. Increasing the "switch to gas" SOC point, however, means decreasing the size of the "usable window" (the "full charge" SOC point remains where it was). The 65% usable window of a battery that had degraded over time enough to cause PPR problems when driving in Extended Range Mode was now, after the procedure, a "less than 65%" usable window of that degraded battery. A programmed reduction in the size of the usable window means the loss of kWh Used in a full charge would not be recoverable via the full charge/full depletion cycle method.

So, did the repairs to your Ampera include "fixing" a PPR problem (paperwork might reference the Bulletin PIC6292C)?
 

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Discussion Starter #14 (Edited)
I heard about that PPR update caused problem especially on 2013 models,there's been a recall for that one. From what the technician said, it's not the same software but I can't find on my paperwork any information about the software they used, only that is for reprograming 2 modules,HPCM2 and BECM. I've never ever have PPR message in 5 years. I hope that they didn't put the wrong update for my car.
After the update also from my 10 bars of range, I loose every one at 0.9 instead of 1-1,05kwh that is used to. So today I used 4 bars and 3.6kwh.
 

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Now, that is good news ("After the update I was limited to 9.7 kWh. The range has increased to 10.4 kWh")
I got my Lifetime 2.7 L/100km (87mpg) on 56k miles. I drive 90% in city but with alot of short stops that affect my range. on the freeway I drive with 130km/h (80miles), but only use EV mode in city, on the freeway on that speed is not worth it.
I onso average 7km/kwh but as I mention, if I drive 7km with one kwh and stop for five minutes then go, with the next kwh I drive like 4-5km max. I guess GOM doesn't have time to estimate, that is why for better callibration is better to leave it 2hr before plugging in. Long stops doesn't affect my range, but I noticed that my AC working harder and consume more than before the update. Maybe is just autosuggestion but is sees louder and eats alot of juice.(When I got SHVCS essage,one error code was for low AC cooling agent, that was refilled)
P.S How do you know exactly how many miles you drive on EV and how much on ICE? Using a OBD I guess...
I have 40.9Ah(about 14.7kwh) available battery, from 45Ah when the car was new.
I use the displayed "kWh Used" number, multiply that by a correction factor of 1.148 for charging losses, and record the resulting number in a spread sheet together with the miles driven in the electric mode, as well as any miles driven with the generator and the gasoline consumed (Charge Sustaining Mode). I have recorded every driving event since new (in the neighborhood of 1,100 entries so far <grins>). Summing those numbers gives me the total miles driven in electric mode and in Charge Sustaining Mode. I believe that my numbers give me a fairly accurate representation of the efficient of my car with my driving style.
 

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Discussion Starter #16 (Edited)
(y)Holly cow, "jbakerjonathan" seems like you really keep an eye on everything. I thought is't something that tells you exactly how many electric miles did you drive.
Just a assumtion:
If with myvoltcappacity I get 40.9Ah of battery life that multiply by 360V = 14,72Kwh lef, from 16kwh when the car was new. What if my car now, after the update use 65% of 14.72kwh instead of 16kwh that supose to calculate before the update. Maybe after the update it recalibrate all to real available capacity.
That means 9.56Kwh, seems to fit the situation. I hope I'm wrong, I just got back from a drive around town for complete discharge of the battery and I've got 65km with 9kwh used so 7,2km/kwh.
 

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(y)Holly cow, "jbakerjonathan" seems like you really keep an eye on everything. I thought is't something that tells you exactly how many electric miles did you drive.
Just a assumtion:
If with myvoltcappacity I get 40.9Ah of battery life that multiply by 360V = 14,72Kwh lef, from 16kwh when the car was new. What if my car now, after the update use 65% of 14.72kwh instead of 16kwh that supose to calculate before the update. Maybe after the update it recalibrate all to real available capacity.
That means 9.56Kwh, seems to fit the situation. I hope I'm wrong, I just got back from a drive around town for complete discharge of the battery and I've got 65km with 9kwh used so 7,2km/kwh.
Yes, the displayed kWh Used is not an absolute measurement. However, the variables in the calculations are minimized when over 1,100 entries are averaged.

Steverino wrote a very good explanation of the "estimated" kWh Used display.
 

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Discussion Starter #18 (Edited)
I'm on the 9'th full charge/discharge cycle and now every 0.8kwh-0.9kwh used I lose one energy bar from 10. So today on 5.2kwh used I've got 4 bars remaining. This is not a normal callibration and I understand that there is no way of reflashing the old battery module software back. 60km with a full battery it's dissapointing.
Even if everybody said it's a guessometer and it's not accurate, I want my old guessometter back because it let me drive 70km and use 10kwh minimum. How it supose after 10-12-20 cycles relearn minimum and maxium of the battery? I don't think in one morning I start the car after 12 cycles and BAM 70km estimate and 10.2kwh used. It supose to get better with everyday eventually not the other way. I even drive without short stops, AC on minimum, no Sport Mode, summer tyres with correct pressure, temps outside are of 28C....
Also this topic is similar to my situation and said that many see permanent loss of kwh after the update:
 

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Interesting reading especially for the 2014 volts. I have 2014,about 81,000 miles with 90% from electric driving only, the battery rating usage was 10.7 for us at the 38miles BUT after now 7yrs by this October 2020 I still get 10.2+ out of the battery and regularly get over 38miles out of it easily from spring through late fall with of course less miles because of the NY cold. I HAVE NOT applied that cell re-balancing bulletin mostly for similar reasons that LUMOS points out above. I hope to be in a BEV and can note this to whoever likes to get it done that owns the car after me then .....hoping nothing crops up until then.
 

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Discussion Starter #20
After the firmware update was done to my 2014, the reported used capacity has dropped from around 10.4kWh to around 9.5kWh. It's been about 10 months, a bunch of full discharge in that time. I think there is permanent degradation of the battery pack, I'd have expected re-calibrate to have occurred by now.

In retrospect, after 6 years, it's foolish to think there would be no noticeable battery capacity loss. Meaning that seeing none reported by the car after this time should have been telling me something. We'd read on this forum rationalizations that the GM did this by gradually reducing the unused capacity at the bottom and top end ( bottom ~20% and top ~ 20%) but this was really a guess - none of us knew if this was really true, it just seemed to fit the situation.

A FW bug that breaks or disables cell balancing is a very large whoops - it's hard to see how this wasn't detected for so long. It's so large an oversight I kinda wonder if it's really true, and especially wonder what the rest of the story is.

I'd hoped my car would gain back some battery capacity, but instead I'm finding that it can be even lower the the typical 9.4kwh these days. When it's cooler weather, it seems especially prone to engaging the gas engine early versus letting you get those last bit of 'fumes' out of the battery.

Lumos
2014 Gen 1 ~ 58kmiles
I think there are 2 different updates, one for PPR message that do reballancing of battery cells and one like mine, that is reprograming HPCM2 and BECM modules due to loss of isollation on cooling sensor. I don't think mine does the reballancing, only reset the battery callibration that has to relearn after. I understand that after the update is done it supose to put the car on charge immediately, if not it will take alot more time to relearn.
 
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