Reprogram BMS to use full cell capacity of 2014 LFP pack

[two20142lts]

Both my 2014 sparks are aproaching 100k miles and are down to 55 miles on the guess o meter at full charge. These A123 cells are rated for 3.6 volts at full charge and 2.5 volts empty. But I've noticed both cars only charge the cells to 3.35 volts. Is there a way to change the GM BMS programming so the cells will charge and balance to the A123 specs ie 3.6 full to 2.5 empty? My warrantee is almost up and I was thinking I could get some range back.

I have found a source for LFE pouch cells of the same physical size with better amp hr ratings so as far as I can see it would possible to rebuild the pack and get better than new range of around 115 miles even without being able to change the BMS parameters. It's a long but interesting diy project.

I am also looking to buy a complete used pack for a 2014 spark if anyone has one.

 

[Infinion]

Hey,

a bit late to this reply but Ingenext has a the battery pack from a salvage 2014 spark using the A123 cells here:
https://ingenext.ca/collections/chevrolet-spark/products/chevrolet-spark-ev-battery-spark-95381721

You could attempt to email them and ask about how they have maintained the pack SoC, current state of the cells, capacity, etc.

If the odometer is indeed 71,000 km, that means there has been roughly 645 charges. LIFEPO4 should be able to do a couple thousand charges before losing significant (20%) capacity compared to LG's lithium cobalt chemistry, but ofcourse leaving fully charged or discharged would change that a lot, so driver habit would be a big factor, and the battery doesn't contain any comprehensive logs :?

 

[NORTON]

I have found a source for LFE pouch cells of the same physical size with better amp hr ratings so as far as I can see it would possible to rebuild the pack and get better than new range of around 115 miles even without being able to change the BMS parameters. It's a long but interesting diy project.

This is awesome to hear!
Please keep us posted! Could you share this info on the cells?

I'm not needing anything now. On my '14 I still see 68-72 mi. on the GOM. And this is mostly 70-80mph on a 50mi a day commuting.
Of course winter is much less....

 

[gnafuthegreat]

I can create a new topic if it makes more sense, but I figured I'd piggyback off of this old one to start. My questions are in the same vein, and I'm also curious what upgraded cells two20142lts found back in 2021 ;-).

I recently purchased a 2014 Spark EV that is running well but has definitely seen some degradation. However, how much depends on which numbers I believe. I've seen the following claims on this forum:

• Depth of discharge is 81% giving you ~17.3 kWh usable capacity out of a 21.4 kWh pack

• Depth of discharge is 93% giving you ~19.9 kWh usable capacity out of a 21.4 kWh pack

I've seen users reporting a capacity of 18-19 kWh in their 2014 Sparks, so it must be possible that some did ship with either a higher DoD or a larger capacity pack. However, I have seen others that seem to confirm the 81% figure. Lastly, my own seems to be 81% based on OBD readings and the energy usage screen:

• 41.6 Ah translating to 16.64 kWh at 400 V

• 13.5-14 kWh usable capacity

• 16.64*0.81 is 13.48

Do I have ~78% of my original capacity and an 81% DoD, or ~68% with a 93% DoD? It seems I have 16.64 kWh of real capacity and 93% of that could be close to 15.5 kWh. That would give me a lot more range!

This leads me to the same question as the OP: Does anyone know what it would take to reprogram the BMS to expand the DoD on a 2014 Spark EV? Is it possible to obtain some kind of update based on later 2014s that had a 93% DoD? What kind of equipment is needed, and has anyone on this forum tinkered with reprogramming the BMS?

I love this little car and I hope to drive it for many years to come. Its current usable capacity is enough (I get 60-64 miles on a full charge with air conditioning during the summer), but I dream of a day when I can either unlock more of what's there or swap out the cells for modern higher-capacity ones.

 

[gnafuthegreat]

Okay, I came across this slightly older thread:

https://mychevysparkev.com/forum/viewtopic.php?t=9213

And it seems maybe a bulk of the reserved capacity is at the bottom rather than the top (fully charged is 98% actual?). I guess if that's true there isn't much or really anything to "unlock" safely. (Though maybe that doesn't apply to the 2014s...)

That said, I'm still interested in higher-capacity LFP cells to do an upgrade someday ;-).

 

[NORTON]

..That said, I'm still interested in higher-capacity LFP cells to do an upgrade someday ;-).

Are you going to wait for the original A123 LFP pack to degrade to an unusable state?

You may be waiting a long time!
Mine is going strong at 98k miles!

 

[gnafuthegreat]

..That said, I'm still interested in higher-capacity LFP cells to do an upgrade someday ;-).

Are you going to wait for the original A123 LFP pack to degrade to an unusable state?

You may be waiting a long time!
Mine is going strong at 98k miles!

I'm very encouraged by your experience, that's for sure! I do wonder whether it's going to level off now that it's seen around 20% degradation or if I have to expect it to continue to slowly get worse. I'm trying to be prepared for an eventuality where the usable capacity is below my needs but I'm not ready to give the car up. It also seems like it's not so much the miles but the calendar life because mine only has ~38,000 miles on it so far.

There's a large part of me that wants to keep this car long enough to get collector plates for it and take it to classic car shows ;-). It's such a quirky little piece of automotive history!

EDIT: I've only had the car for just short of two months, so I have no idea how much of this degradation happened with the previous owner vs. the one before him. The guy I bought it from knew EVs and seemed to take very good care of it, so any outright mistreatment of the battery likely came from the owner before him.

 

[NORTON]

.....
There's a large part of me that wants to keep this car long enough to get collector plates for it and take it to classic car shows ;-). It's such a quirky little piece of automotive history!

EDIT: I've only had the car for just short of two months, so I have no idea how much of this degradation happened with the previous owner vs. the one before him. ...

Have a sign at this future car show in front of your Spark EV:
The Father of the Bolt.
Chevy's 2nd BEV!

It's also hard to find the original '14's claimed kWh rating for the pack, which is needed to state % of degradation.

 

[Porsche]

]Have a sign at this future car show in front of your Spark EV:
The Father of the Bolt.
Chevy's 2nd BEV!

How timely. I may be showing my 2015 at a car show tonight. Maybe I'll make a quick sign just like that. Hmm, maybe I'll say "1st PRODUCTION BEV", or "1st BEV sold by Chevy", or something. The EV1 was more of an experiment than an actual production car.