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They only recalled about 3223 2013 Volts. Probably a very specific software update. GM actually tracks certain software updates for Volt individually by VIN.
 

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Discussion Starter #3
Yes looks like this update caused the issue,

In its latest recall notice, GM notes that an update to the hybrid powertrain control module in 2013 Volts may have disabled the cell balancing function.
 

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I was reading a similar thread the other day here and I went to gm recall site and put in my VIN and it told me I was good.

Guess I never had the update.
 

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Yes looks like this update caused the issue,

In its latest recall notice, GM notes that an update to the hybrid powertrain control module in 2013 Volts may have disabled the cell balancing function.
Disabled?!?!?
 

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As of 6/23/2018 our 2013 has no open recalls or suggested service except low inflation pressure.

Dad is the ONLY human in the family who knows that tires are pneumatic and what a Low Pressure Icon looks like.

And she isn't recharging it as often as I'm asking her. It's down to 59% EV miles from over 90% when she left for college.
 

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Disabled?!?!?
If BMS balancing is disabled, welcome to world of electric propulsion. BMS is not used in all Lithium Ion batteries, a very few NiMH, and pretty much no Lead or NiCad arrays, not even on 2018 model 4000lb forklift batteries. Forklifts use lead because they need the weight more than the power.

BMS is handy for rapid charging where overcharging is immediately dangerous, but you want maximum kWh storage.

But since a Volt is not charged to 100% to begin with, the C charge rate is low, the worst case is a weak cell could eventually lose capacity.

Now if the BMS balancing is off on a car charging at 40-120kWh to 100%? Be very, very worried. This can start a fire if there is a weak module. It will charge to the proper peak voltage, but they are in series. If one or more is lower voltage, the others will get overcharged past 4.2x and heat up rapidly.
 

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Maybe this is why many of us with 2013’s are seeing kWh use in the 8.9 to the 9.x range off and on. I am on the recall list. I have not had a reduced propulsion issue though so I am probably ok for the time being.
 

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If BMS balancing is disabled, welcome to world of electric propulsion. [which varies a lot by manufactuer]
...
Be very, very worried. This can start a fire if there is a weak module. It will charge to the proper peak voltage, but they are in series. If one or more is lower voltage, the others will get overcharged past 4.2x and heat up rapidly.
Wonder if this software bug will ruin some Volt batteries or change their lifespan.
Too bad they couldn't fix this potentially dangerous situation with an OTA update.

 

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Wonder if this software bug will ruin some Volt batteries or change their lifespan.
Too bad they couldn't fix this potentially dangerous situation with an OTA update.

I think the most important OTA update needed today is the 'put out Tesla fire' update.

If you have high production standards, cells tend to very closely matched, unlike the 3:1 ratio you are describing that occurs with cheap 18650 cells. I have a couple dozen loose 2012 Volt LG cells, and the entire spread after 6 years is under 0.010 volts.
 

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I have a couple dozen loose 2012 Volt LG cells, and the entire spread after 6 years is under 0.010 volts.
Doesn't sound like you think GM needs a BMS at all then and they don't even need this recall :) If you are worried about Tesla fires then cancel your reservation. :)

Note the above is from a GM related presentation.
 

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Doesn't sound like you think GM needs a BMS at all then and they don't even need this recall :) If you are worried about Tesla fires then cancel your reservation. :)

Note the above is from a GM related presentation.
To get the longest life possible balancing is always a good idea. Is it dangerous not to have it? It depends.

Does Tesla have balancing? How many cells are balanced per wire? GM is 2-3 cells per wire.
 

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Discussion Starter #13 (Edited)
Wonder if this software bug will ruin some Volt batteries or change their lifespan.
Too bad they couldn't fix this potentially dangerous situation with an OTA update.
This looks right, and with an unbalanced pack, and assuming all cells have equal performance capability, the pack won't charge to 100%, and you can't discharge it fully either. Balancing occurs on a trickle "discharge" basis. Tiny resistors are switched across the high cells to bring them down to match the rest of the pack. It requires time and cycles to bring the pack into balance. This is not an instantaneous thing.
 

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To get the longest life possible balancing is always a good idea. Is it dangerous not to have it? It depends.

Does Tesla have balancing? How many cells are balanced per wire? GM is 2-3 cells per wire.
Many discussion on Tesla balancing over the years. More on Model 3 recently.

I have two apps that I can use to watch my Tesla 'live' charging / balancing.

Highlevel overview numbers (vs breakdown of each group) from my Tesla X a short while ago. I'd say it's balancing works with 0.007 difference of min and max :)

 

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Has anybody found PIDs that shows Cell Max Voltage and Cell Min Voltage?

I want to see if my 2013 Volt cells are balanced.
 

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My 2013 is on the recall list too. It is an early build, a PEP/Special Event manufacturer's vehicle put in service 8/29/12. It was never registered to a private owner until I bought it. Car only has 30K miles on it, screen shows 10.4 -10.5 battery usage before the ICE comes on, so I am assuming that the battery is still healthy. I'm just waiting for the formal notification and availability of the reprogram info.

I have an ebike with a 36v, 12Ahr LiFeP04 battery pack with a built-in battery maintenance module. It will charge up, stop charging, and then in a few minutes start charging again. This cycle repeats a few times. One time I noticed the Volt doing the same - is this the balancing process?
 

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Can those with access to GDS2 confirm what HPCM2 software they have and whether or not they are on the recall list?

My 2013's HPCM2 has the current latest calibrations, 23206093 (operating system) and 24281683 (calibration). But I updated them myself so I wonder if GM is referring to the original software or the newer version. Can GM even tell when a vehicle is updated vis SPS?

The TIS2Web page for the HPCM2 was down for the past week so I had assumed GM pulled access to it to avoid anyone else updating to the faulty software. But now its back up with the same software so perhaps the bug was only on older versions and GM just pulled it temporarily while the confirmed it was not on the newer software too. But thats just a guess.
 

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Do you suppose this is just balancing between the 3 sections? Most cells would normally balance with other cells within their group and then there would be balancing again within the series/parallel and then again between the sections? If it were far out of balance I would think it would throw codes. We are probably lucky we are charging within the middle available storage and never taking the battery too high or too low.
 

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