New Bolt EV Batteries and no BMS, one year observations.

Darren Orange

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About one year ago I purchase and set up about 13.5kWh useable Bolt EV batteries that where new from batteryhookup. For this year I have operated without a BMS. I actually have two batteries technically in parallel a 14S2P setup. My new Chevy Bolt EV battery modules(for my home power system) after about 1 year of near constant use mostly in the range of 3.357V to 4.071V (47V to 57V). I have found that even to this day at the lower range of the voltage I only see about ~.03V variance with no BMS. I don't know for sure but I am pretty sure that is well below a BMS or balancer to actual do any balancing. What is more impressive that many of the cells have nearly or exactly the same numbers in example today most of the pack was either 3.428V or 3.351V. I don't know if anyone else has experience with new extremely high quality batteries but is this typical behavior or perhaps something to do with how high spec the battery is? I have BMS to install on the batteries and while I know they offer extra protection and such I find this hard to believe it has managed to stay this balanced without any actual balancing based upon others experience with other batteries. Anyway Just my observations. I figure someone might find this information useful.
 

toms

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If you have well matched cells to begin with, that is normal behaviour. I have a BMS, but the balancer often goes years without operating.
 

Dr. Dickie

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If you have well matched cells to begin with, that is normal behaviour. I have a BMS, but the balancer often goes years without operating.
Yep, same here.I haven't gone a year, but about 6 months. I have my solar system set so it quits charging just before the by-pass voltage for the packs (I built the packs from LG M-26 cells myself). And the packs are within 10 mV, as they have been from the start.
 

A.Justice

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EV batteries are one of the few ways a consumer can get genuine grade A+ matched cells at a reasonable price. They may be used, but are most likely perfectly matched from the factory.
 

NwCali

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It might go great for years...

But in the event a BMS was needed and you didn't have it......

No doubt though eventually a BMS will cause a problem/fire..
 

toms

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No doubt though eventually a BMS will cause a problem/fire..

If you are patient enough, every electrical item in your life will cause a problem/fire. My BMS isn’t close to the top of things most likely.
 

400bird

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If you are patient enough, every electrical item in your life will cause a problem/fire. My BMS isn’t close to the top of things most likely.

Yeah, I've got to think his post you are replying to was a typo?

Maybe, "no BMS = eventual fire"?

I 100% agree. Backup/safety systems are important.
 

ed209

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FYI:

All Bolts are up for recall.
 

Cheap 4-life

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My battery bank is used gen2 Chevy volt batteries from several different vehicles combined into one large battery. They stay very well balanced within 25mv. Bms hardly ever balances
 
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400bird

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I'd have to say that GM/LG would be working really hard at fixing it with "BMS and balancing" if they thought it was at all possible.

Oh wait, they tried that and they still had some catch fire!

I've got an 2019 Bolt in the driveway and about 1/2 of a 2020 pack in the battery box.

The car in the driveway has a build date right in the two month build date range that Electric lists as the most problems.

At least my battery box is in the backyard, 5' from the house and the box is steel.


Not excited about either battery right now.
 

400bird

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I have used gen2 Chevy bolt batteries from several different vehicles combined into one large battery. They stay very well balanced within 25mv. Bms hardly ever balances

Do you mean "Volt" batteries?

Two Bolt packs would be 120kwh and I've never heard of any reference to gen 2 Bolt packs.
 

ed209

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At least my battery box is in the backyard, 5' from the house and the box is steel.


Not excited about either battery right now.
Good luck with that. Hopefully it’s just their BMS setup and not the cells themselves, since they specifically mention not discharging them low.
 

Darren Orange

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BMS are being integrated now. So far results have found that the batteries after this time have remained in spec. ~.02V difference. I'll be adding the second BMS tomorrow and actually hooking them up to allow them to cut off the power later this week. I guess it might do some sort of balancing once the cells are above 4V but not much, the default setting in the BMS is .015V so I'm not sure what to expect. I almost never end up charging them that high except in winter.

I am aware of the Recall I own a Chevy Bolt EV that was originally part of the recall I currently have a loaner car from Chevy a rental car. I have reached out to Battery Hookup where I purchased the battery packs and I am waiting to hear back from them. They where not aware of the recall but are looking into what to do or how to handle the situation.
 

HRTKD

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It will be interesting to see if there is any recourse for Bolt batteries that have been removed from the vehicle. My guess is that Chevy isn't going to do anything about them. Battery Hookup is a different matter. The liability involved, once they know that Chevy is recalling them, has to be significant.
 

electric

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I find this hard to believe it has managed to stay this balanced without any actual balancing
Why is it hard to believe? Battery is designed to last 8-10 years, so you operated it for 10%-15% of its life, it's still like new, so no need for any maintenance. There is never a need for balancing on a healthy battery. Balancing is a crutch, and a very poor one at that, designed to try and prolong a life of a battery with some inherent problem. In most cases it can't fix it, just trying to postpone the inevitable.
Real use of the BMS is to prevent charge/discharge of a battery which is experiencing either internal ( cell failure ) or external ( equipment failure ) fault. Since you haven't experienced such faults ( yet ), the lack of BMS wasn't notable. Since you use the battery with very conservative operating voltages ( good idea ), you might run for years without trouble, but some day you might regret it. Just like not buying insurance for a car or a home.

BTW, all the talk about BMS failing to prevent Chevy Bolt fires is nonsense. No BMS can prevent a fire caused by cell manufacturing defect, which can't even be detected until it happens, at which point it's too late to do anything. The best BMS can do is blaze the horn, so people can wake up and run from the house, while garage is burning. They tried to update BMS software to better detect the issue, but it's futile, so now they are replacing all batteries. Worst situation possible. Thank you LG for ruining EV market. All because of shitty QC on the production line.

In case I sound too pissed off, it's because I own a 2018 Bolt and cross my fingers every time I charge it, until my number comes up for battery replacement. Otherwise I love the car, it's such fun to drive and costs half of Model 3.
 

Darren Orange

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Why is it hard to believe? Battery is designed to last 8-10 years, so you operated it for 10%-15% of its life, it's still like new, so no need for any maintenance. There is never a need for balancing on a healthy battery. Balancing is a crutch, and a very poor one at that, designed to try and prolong a life of a battery with some inherent problem. In most cases it can't fix it, just trying to postpone the inevitable.
Real use of the BMS is to prevent charge/discharge of a battery which is experiencing either internal ( cell failure ) or external ( equipment failure ) fault. Since you haven't experienced such faults ( yet ), the lack of BMS wasn't notable. Since you use the battery with very conservative operating voltages ( good idea ), you might run for years without trouble, but some day you might regret it. Just like not buying insurance for a car or a home.

BTW, all the talk about BMS failing to prevent Chevy Bolt fires is nonsense. No BMS can prevent a fire caused by cell manufacturing defect, which can't even be detected until it happens, at which point it's too late to do anything. The best BMS can do is blaze the horn, so people can wake up and run from the house, while garage is burning. They tried to update BMS software to better detect the issue, but it's futile, so now they are replacing all batteries. Worst situation possible. Thank you LG for ruining EV market. All because of shitty QC on the production line.

In case I sound too pissed off, it's because I own a 2018 Bolt and cross my fingers every time I charge it, until my number comes up for battery replacement. Otherwise I love the car, it's such fun to drive and costs half of Model 3.
If you call and complain to GM/Chevy EV hotline they will put you in a loaner car free of charge and pay for your gas. I'm currently also working on a buy back on my 2019.
 

electric

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I have reached out to Battery Hookup where I purchased the battery packs and I am waiting to hear back from them. They where not aware of the recall but are looking into what to do or how to handle the situation.
Your packs are from Volt, which never had a battery recall AFAIK. Even though Volt packs were also made by LG, it's a completely different module design, likely made on different production line, where drunk or blind QC team wasn't allowed in :rolleyes:
Many DIY batteries were made with Volt packs, quite successfully, so your aren't alone in the happy camp. Just treat it well and it'll serve you for many years. EV batteries are supposed to get a second life in solar storage, so you are doing the ring thing.
 

electric

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If you call and complain to GM/Chevy EV hotline they will put you in a loaner car free of charge and pay for your gas. I'm currently also working on a buy back on my 2019.
I'm a true EV nut, would never settle for a gas loaner. Even though my Bolt has a risk of battery failure, probability is very low, plus I treated my battery well since day one ( being a battery engineer for a living helps ), so risk on my specific battery is even lower than average. I think I'll ride it out until replacement comes.
I'm actually more worried about replacement process. I read that batteries will not be replaced as a whole unit, but rather taken apart and cell modules replaced, to save costs on BMS/box/wiring replacements. This is great for bean counters, but I hope the work won't be done at a local dealer, as it requires special skills and QC to avoid new problems. Packs should be sent to GM factory where highly trained team would fix them, test them and return to dealer.
On a positive side, we'd be getting a new battery on a 3 year old car. I usually keep my cars for many years, so this works well for me.
 
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