Leaf Service EV System Adventures with P0AA6-1A and a Suspect 12V Battery

[knightmb]

You have a healthy 12V battery, so it's more difficult to use up so much power that the Leaf needs to top it off, which is a good problem to have.

You bring up a good point that I didn't think of. Way back when, my 2013 would sit in this mode "forever"; even taking cycles to charge up the 12V battery then stop, then if the 12V battery was depleted again, it would energize to charge it again. It may have been changed, perhaps at the 2018 year models to just turn off after 15 min no matter what you do; to conserve power? I've never just left my "newer" model years running before, so I guess that is an easy test I can do on both of them outside and report what I found here.

I may be wrong though, I think I remember reading that you have a 2015? Maybe this was changed much earlier in the model years?

 

[cornbinder89]

Yes, I have a 2015

 

[knightmb]

I had time to preform two test today on my wife's LiFePO4. The first is a capacity test to see what level the 12.8V battery was charged to while in her Leaf when I took it out. The test is a lot faster since Lithiums are drained over an hour instead of 20 hours.

To summarize, it took while to figure out a combination of small space heaters and fans to get the energy draw as close to 256 watts as possible. Also, this battery is considered depleted at 10.5V not 10V like a FLA / AGM battery. Regardless, the first test result was kinda not surprising given it's +9 years of age.
My test load was running at 230 watts (about as close as I could get this) until the voltage hit 10.5V. It only took 35 minutes to hit this voltage, so 35 min / 60 (1 hour) = 0.58 Hours. That works out to 230 x 0.58 = 133.4 watt hours. The battery is rated for 256 watt hours, so more math, 133.4 / 256 = 0.52 or 52% of the rated capacity.

LOL, only about twice as good as the FLA that replaced it.

I was curious though, would it perform any better if I "fully" charged it and then ran the same test. I doubt the Leaf is keeping it at 100% SOC all the time. So, charged it back up with a 12V charger, once it hits 14.6V is disconnects from the 12V charger and shows up immediately as "full", so I went with that rather than try to keep floating up the charge to 14.6V over and over.

Did the same test and was surprised it actually did better. This time I was about to 45 minutes (I always round down) of run time. So, run it through all the math again, 45 / 60 (1 hour) = 0.75 Hours, 230 * 0.75 = 172.5 watt hours, so this time it got 172.5 / 256 = 0.67 or 67% of the rated capacity. Interesting...

So my wife's 2018 Leaf is running it at around 52 / 67 = 0.78 or 78% of a full charge. That might explain why these Lithium batteries live so long, they never sit at 100% SOC all the time. Makes me wonder what happens to a FLA / AGM though if you were operate them the same way.

 

[knightmb]

I just finished my "power on to standby and just sit until it turns off automatically" test on both 2018 and 2020 Leaf. Both clock in at exactly 10 minutes. It does not matter if I leave the key fob in the Leaf or away from it where it can not be detected, it's always 10 minutes exactly. Quite a change from my 2013, you could leave it in this "mode" forever. Learn something new every day.

 

[boontis]

Very informative thread - I have been following this over the last several days learning - but after being stranded on the side of the freeway today I'm jumping in with related question:

Today I was driving uphill doing 90KMPH and all of a sudden my dash lit up like a christmas tree. I got turtled and managed to get over to the side of the road. (just barely) I was getting the "service 12v charge system apply parking brake" warning and "service EV system no power". The car would turn "on" but wouldn't let me put it into drive - it just kept bumping back to park. I have pics from Leafspy not even 2 weeks ago showing my 12v batter was at 14+ volts, but when I plugged in Leafspy on the side of the road it was showing between 8.5v and 11v. (kept swinging up and down)

When the tow truck arrived, I went to turn the car on and put it into neutral and the dash just clicked repeatedly. The tow truck driver had a battery booster and once he hooked that up, the car came back fully and after driving to the dealership I was still able to start the car and drive it off the tow truck. (the booster was only on the battery for maybe 5 minutes, and then the drive was about 15 mins, then I tried to start it again and it worked fine)

My question is: Once the vehicle is driving, can a bad 12v battery take down the car and strand me like it did? That seems crazy as I thought it draws from the main battery when driving? (as has been discussed in this thread?)

I am also monitoring some potentially weak cells - hence why I had leafspy and the dongle handy - so could that have played into this? I did notice that the SOC was 27% when my dash lit up, but immediately jumped back up to 44% once I stopped. (Nowhere near 0%.)

Based on this thread I'm tempted to call the dealership to tell them to just leave my car, and I'll come tomorrow with a new battery and swap it myself, but I'm curious if my situation could be something bigger with the main 40KWh battery? (I have a 2018 SL) Thoughts? They want to charge 4 hours at $160 per hour to diagnose the main battery for potentially weak cells...so I'm not eager to go that route if it's just a simple 12v battery issue...

 

[cornbinder89]

When driving, the 12 volt should be charging PERIOD. How it chooses what rate and voltage is done by the post temp and how much current is going into the battery.
Turtle suggest the traction battery crashed, it couldn't supply power to the traction battery or the 12 volt battery. I wouldn't say one or the other is a sure bet. This one needs some diagnostic time, either by you or the dealer. It is hard to sort out cause from effect at this point.
IF it were mine, I would charge and then test the 12 volt, clean terminals and record and clear codes. Then see what happens.
The jumping from low to higher, is a symptom, not a 100% of anything .
A 100% loss of the 12 volt should drop the car into neutral and not turtle, It may be hard in the spur of the moment to notice the difference.

 

[boontis]

When driving, the 12 volt should be charging PERIOD. How it chooses what rate and voltage is done by the post temp and how much current is going into the battery.
Turtle suggest the traction battery crashed, it couldn't supply power to the traction battery or the 12 volt battery. I wouldn't say one or the other is a sure bet. This one needs some diagnostic time, either by you or the dealer. It is hard to sort out cause from effect at this point.
IF it were mine, I would charge and then test the 12 volt, clean terminals and record and clear codes. Then see what happens.
The jumping from low to higher, is a symptom, not a 100% of anything .
A 100% loss of the 12 volt should drop the car into neutral and not turtle, It may be hard in the spur of the moment to notice the difference.

Interesting - here’s what my dash looked like when I got to the side of the road - so much going on maybe it wasn’t turtle?

 

[cornbinder89]

Just way to hard to tell with a snap-shot. With the car driving, the HV relays are in and the Dc-DC charger active for keeping the 12 volt up. Your dash seams to be saying that was not working and the system shut down.
Just as a dead cell or battery doesn't kill an alternator on a conventional car, the same should be true about the Leaf's system.
So was the low battery caused by an in-op system? why didn't the Dc-DC maintain the car until being shut down?
It is tempting to try and make it something simple, but without looking into the cause, and only jumping to conclusions without trying to get to the root of the problem will very likely come back to bite you.
A conventional cars alternator output is based on engine speed, and at low speed may be overwhelmed by the load. The Leaf's DC to DC converter can supply the same amount of power regardless of if the car is moving or stationary. The fact it came back and drove to the dealer, says it is an intermittent problem, and you may think you have solved it, but may not. SO before replacing any part, I would want to review DTC's and charge and test the 12 volt. A discharged battery is not a defected battery, and replacing a discharged battery with a charged one, may make the problem go away in the short term but have it bite you again when you least expect it.
The DC-DC looks at the current flow into the battery at the voltage applied. IF the battery terminal connection isn't good, the DC to DC is going to see low current going in and high charge voltage, and start scaling the charge back to float voltage, but the battery is not receiving anything. Sooner or later the system will crash. I am not saying this is what is happening in your case, just an example on how the 12 volt could become discharged.
If you want to diagnose it yourself, then take the car home, if you want to have Nissan do the diagnoses then leave it at the dealer. IF you want to throw a battery in an hope, do that, but know that it may not fix and you will be out the money.

 

[boontis]

@cornbinder89 Thank you for the level headed response. I appreciate you laying out some potential scenarios and the pros and cons. I asked the dealership to have the tech call me before doing anything so I’ll ask them to start with the diagnosis on the 12v battery and go from there. I don’t have the time to do it tomorrow myself due to work although I really wish I could!

 

[nlspace]

but when I plugged in Leafspy on the side of the road it was showing between 8.5v and 11v.

Those voltages are too low and indicate a possible issue with an old, weak or worn out and depleted battery.

The dash is showing that at the cold temperatures (-5C) your 12V battery is not up to the job. The chemical reaction inside the battery is reduced by cold temperatures, for both load and charge current.

What is age of your battery, is it the original? Then i'd say you got your money's worth out of it.

The whole point of this thread was to demonstrate how a failed battery can "appear" to be okay, but it is only an illusion.

Once you resolve your 12v battery issue, the other problems typically "heal" themselves.

 

[knightmb]

Very informative thread - I have been following this over the last several days learning - but after being stranded on the side of the freeway today I'm jumping in with related question:

Today I was driving uphill doing 90KMPH and all of a sudden my dash lit up like a christmas tree. I got turtled and managed to get over to the side of the road. (just barely) I was getting the "service 12v charge system apply parking brake" warning and "service EV system no power". The car would turn "on" but wouldn't let me put it into drive - it just kept bumping back to park. I have pics from Leafspy not even 2 weeks ago showing my 12v batter was at 14+ volts, but when I plugged in Leafspy on the side of the road it was showing between 8.5v and 11v. (kept swinging up and down)

When the tow truck arrived, I went to turn the car on and put it into neutral and the dash just clicked repeatedly. The tow truck driver had a battery booster and once he hooked that up, the car came back fully and after driving to the dealership I was still able to start the car and drive it off the tow truck. (the booster was only on the battery for maybe 5 minutes, and then the drive was about 15 mins, then I tried to start it again and it worked fine)

My question is: Once the vehicle is driving, can a bad 12v battery take down the car and strand me like it did? That seems crazy as I thought it draws from the main battery when driving? (as has been discussed in this thread?)

I am also monitoring some potentially weak cells - hence why I had leafspy and the dongle handy - so could that have played into this? I did notice that the SOC was 27% when my dash lit up, but immediately jumped back up to 44% once I stopped. (Nowhere near 0%.)

Based on this thread I'm tempted to call the dealership to tell them to just leave my car, and I'll come tomorrow with a new battery and swap it myself, but I'm curious if my situation could be something bigger with the main 40KWh battery? (I have a 2018 SL) Thoughts? They want to charge 4 hours at $160 per hour to diagnose the main battery for potentially weak cells...so I'm not eager to go that route if it's just a simple 12v battery issue...

First question, when it hit turtle mode, did you notice a loss of power steering or having to pump the breaks to stop? I only ask since those depend on the 12V system and at least if those were still working, there must have been some 12V power in the system at least.

Interesting, so it had power to engage park and neutral it sounds like. When you wrote "The car would turn on", did it actually light up the little green car icon with the arrows underneath pointing forwards and backwards?

Ok, so the 12V booster got the Leaf started and it appeared to function normally then? The voltage readings you were seeing on the side of the road with LeafSpy, my guess those were probably in standby mode (two start button presses to get the dash on, accessories active, etc.)? Depending on how many accessories were running, high power ones can drag the 12V battery voltage down. You might be seeing those 8V to 11V swings because the Leaf is trying to engage the traction battery to help / charge the 12V battery and system, but the battery doesn't have enough power to do it and it fails. Sounds like it was trying over and over to do this.

A bad 12V battery that can't hold a charge basically turns into a heater. Not the scary kind that will catch on fire and destroy the vehicle, but one that waste power. I'm sure with an extreme example with a high enough voltage and current you could probably get a bad battery to do bad things, but I wouldn't worry about that. In the case of the Leaf, it's limited to 2000 watts of power and that doesn't mean it is trying to force all of it into the battery anyway, physics still applies on the limits.

A bad battery that is basically just a power wasting heater will cause problems though and the Leaf 12V system does have safe-guards to prevent power overloads and short-circuits. It's possible something is going wrong in the 12V battery to trigger one of those or as stated by others, could be a symptom of something else wrong in the system.

Weak cells in the HV battery is a whole other universe away from the 12V system. I would focus on one of these at a time. If you have the tools, time and a 12V battery charger with an extension cord (just in case ), you could drive to any auto-store or battery store and let them test it to see if it can even get close to it's CCA rating? Have them do more than one test, heck try 4 in a row to see if the CCA rating is dropping rapidly after each test. If the battery fails even the most basic auto-store level kind of tester then I would consider a replacement that day.

Since you have LeafSpy, you can try a "rough" capacity test. Get LeafSpy connected, without starting the Leaf into drive mode, just start it in standby mode with two "start" vehicle button presses (no brake pedal) so you can power the 12V accessories with no help from the HV battery. While watching LeafSpy, starting turning on more and more power hungry accessories one at a time to see how much power the battery can handle before the voltage starts to tumble quickly. Start with everything off and then try the cabin fan, then the rear window defroster, any other heaters like seats and steering wheel, etc. If the 12V battery can't handle the cabin fan + rear defroster on max for more than a few minutes before the voltage starts to rapidly fall after the battery should be "fully" charged, then it's probably a dying 12V battery.

The video I posted on page two, the whole video was only 3 minutes long, I trimmed it to the relavant section, but that battery could not power the cabin fan + rear defroster for more than 3 minutes before it died and had to be "boosted" by the HV battery. If your 12V battery is depleating that fast like the bad one I'm working with, then I would suspect the battery as the cause of your 12V system problems.

 

[knightmb]

Interesting - here’s what my dash looked like when I got to the side of the road - so much going on maybe it wasn’t turtle?

I do recognize the "Service 12V charge system Apply parking brake" message. That comes up when the 12V battery voltage gets low enough to trip a warning but not enough to completely die. If you check LeafSpy and gather all the DTC info, you should see a DTC for the "14V under-voltage" error I think.
I can't remember exactly how it is worded, a screen-shot would work better I guess if I can find one.

 

[cornbinder89]

I do recognize the "Service 12V charge system Apply parking brake" message. That comes up when the 12V battery voltage gets low enough to trip a warning but not enough to completely die. If you check LeafSpy and gather all the DTC info, you should see a DTC for the "14V under-voltage" error I think.
I can't remember exactly how it is worded, a screen-shot would work better I guess if I can find one.

The biggest question is why that happened while he was driving? All 12 volt loads should be carried by the DC-DC at that point. A dead short in the 12 volt system could cause it to loose power under those conditions but should also trip the 12 volt main fuse, which it didn't.
There is a big difference between a system that doesn't have enough power to go into ready mode and drive, and one that once is there can't stay in ready mode and drive.
If the 12 volt power supply isn't working or isn't working correctly, you can replace the 12 volt battery and within a few days or a week at most be right back where you are now.
The 12 volt "undervolt" error trips at 12. 4 (not exactly sure on the 1/10 of a volt) while in drive mode, this is what happened indicating a lack of DC-DC charging while underway. The trips and safety system worked as planned, the hard part is tracking down what the cause is, and not focusing on the symptoms.
He may have stayed in gear and the aux boost stayed active because the warning is triggered at a point they should still function for a limited time.
Focus on the undervolt while driving and not a discharged battery to get to the root problem. You should never be able to trip that if everything is working.
Edit: I'll add that it looks to be an intermittent problem as well, making it hard to pin down. If it were all the time, the car would not have been driveable once the booster was removed from the 12 volt, or at least not for long.ou
When you add in the drop and SOC and recovery of it, I think there is more going on than just a 12 volt charge problem. My guess is it will take some diagnoses time to solve., and may take driving until the problem come again to pin down exactly what is happening.

 

[boontis]

Thank you all for your insights! I agree that I think I have two separate issues going on that may have come together to create this weird situation:

1 - my 12v battery is toast. I just bought the vehicle last May but have no idea if it's stock or had been replaced, but as I sat waiting for the two truck with the vehicle on, the lcd screen started flickering at one point, and then after turning it off and trying to turn it on again it stopped turning on at all (black screen and clicking by the time the tow truck driver arrived and asked me to put it in neutral) So the 12v was dying fast and hard over that 20 minute time.

2 - potentially weak cells in the main 40kwh battery. I can see in leafspy that under load (accelerating) I have several cells that drop voltage significantly. My guess is that when under load up the hill it reached a point where it wasn't able to provide enough power to drive + keep the weak 12v system charged and that's why I ended up on the side of the road.

Plan is to check step 1 first, then keep exploring! I'll update later today once I have the 12v system tested.

To answer the questions above - I didn't lose power steering, and since I was trying to get it off the road I didn't hit the brakes until I was almost at a stop and there was pulsing and stuttering - almost felt like the regen was trying to engage but couldn't. It only lasted maybe 5 seconds as I was almost at a stop.

 

[cornbinder89]

You must be able to distinguish between a 12 volt that is discharged and one that has failed. I see nothing but the fact it was discharged being shown. It may be faulty, but that is not yet proved to be true. Any battery placed under load and not recharged will show what you saw. We know it wasn't being charged for long enough to trip the warning, what we don't know is how long it wasn't being charged before that warning happened.
Charge the battery test it separately, install it and check the charging system in the car. It should, when placed in ready mode be able to hold a load placed on the battery of quite a few amps, 60-70 and still hold voltage above rest volts.

 

[Stanton]

2 - potentially weak cells in the main 40kwh battery. I can see in leafspy that under load (accelerating) I have several cells that drop voltage significantly. My guess is that when under load up the hill it reached a point where it wasn't able to provide enough power to drive + keep the weak 12v system charged and that's why I ended up on the side of the road.

You can speculate until the cows come home, but if/when #2 happens...all bets are off. And yes: hard acceleration (or high speed) and cold temps exacerbate these issues.
These battery packs are only as good as the weakest link (cell/module/whatever), so the BMS essentially "pulls the plug" when a cell (only takes 1) dips below "turtle" voltage.

 

[cornbinder89]

I agree, and think it may be the root cause. Testing will need to prove it so.

 

[CaptLarry]

Very informative thread - I have been following this over the last several days learning - but after being stranded on the side of the freeway today I'm jumping in with related question:

Today I was driving uphill doing 90KMPH and all of a sudden my dash lit up like a christmas tree. I got turtled and managed to get over to the side of the road. (just barely) I was getting the "service 12v charge system apply parking brake" warning and "service EV system no power". The car would turn "on" but wouldn't let me put it into drive - it just kept bumping back to park. I have pics from Leafspy not even 2 weeks ago showing my 12v batter was at 14+ volts, but when I plugged in Leafspy on the side of the road it was showing between 8.5v and 11v. (kept swinging up and down)

When the tow truck arrived, I went to turn the car on and put it into neutral and the dash just clicked repeatedly. The tow truck driver had a battery booster and once he hooked that up, the car came back fully and after driving to the dealership I was still able to start the car and drive it off the tow truck. (the booster was only on the battery for maybe 5 minutes, and then the drive was about 15 mins, then I tried to start it again and it worked fine)

My question is: Once the vehicle is driving, can a bad 12v battery take down the car and strand me like it did? That seems crazy as I thought it draws from the main battery when driving? (as has been discussed in this thread?)

I am also monitoring some potentially weak cells - hence why I had leafspy and the dongle handy - so could that have played into this? I did notice that the SOC was 27% when my dash lit up, but immediately jumped back up to 44% once I stopped. (Nowhere near 0%.)

Based on this thread I'm tempted to call the dealership to tell them to just leave my car, and I'll come tomorrow with a new battery and swap it myself, but I'm curious if my situation could be something bigger with the main 40KWh battery? (I have a 2018 SL) Thoughts? They want to charge 4 hours at $160 per hour to diagnose the main battery for potentially weak cells...so I'm not eager to go that route if it's just a simple 12v battery issue...

I went to use our 2016 SV last week, and the dash was completely wonky, showing myriad errors, and there I was in the rain with the window down. After all manner of worrying and trying to decode faults from owners manual.. I remembered all the stories from the early days of folks leaving thier leaf at the airport for a month and returning to a dead car ( flat 12v battery). So yes, everything will go to hell once the cheap wet cell 12v battery dies. I remember from old threads that the 12v battery only charges while the car is being driven ( or at least ON) but NOT while it the propulsion battery is charging! Our car gets little use ( we are old). I truly believe that a Sealed AGM deep cycle 12v battery is right for this application, because the computer is ALWAYS discharging the battery...and low voltage kills the typical "starting" type wet cell fast! The battery tray is big enough for large AGM, but the holder is designed for the skinny ( honda starting group 51) thing.

 

[CaptLarry]

This is more of documentation of my experience diagnosing an issue with a relatives 2018 Nissan Leaf. Hopefully this can provide useful information for anyone else in the future that runs into this dreaded error and left stranded.

It started with a call from a panicked relative early in the morning. They tried to start their Leaf in the early hours and got the dreaded "Service EV System No Power" screen. I wouldn't have time to take a look at until around noon, but what choice did they have short of towing it to Nissan and paying a diagnostic fee?

Anyway, fast forward to around noon, I arrive and bring all my equipment and tools with me. The first thing I noticed was the cabin light looked very weak, hmm.
So this is what LeafSpy was able to tell me about their issue (screen shot below). Yeah, that does not look good. But then I noticed the 12V system voltage, it was really low for just getting the dash switched on in standby mode so I could run LeafSpy. 11.44V with only a 24 watt load? I'm starting to suspect the 12V battery. But I don't want to seem like I'm being bias against the poor 12V battery. So I open the hood to take a look at the 12V battery itself. Well, it's an original Nissan factory battery!
Going by the thick later of dust and dirt, no one has probably touched it in years.

Before I start giving the 12V battery the evil eye, I need to check if that P0AA6-1A code is a real concern. Grabbing my socket set and HV gloves I disconnect the 12V battery from the Leaf. I then find a good grounding spot on the frame and then I remove service disconnect from the center of the pack. I use my multi-meter to check both contacts down in the plug to see if any voltages appear between both sides of the pack and vehicle ground. After a long wait for the capacitance to finally zero out the voltage, I am about to confirm that no voltage leaks were found while testing the battery pack. Something interesting I did see after waiting for 0 volts was that the wind blowing across the Leaf was able to generate some Milli-volts of potential from what I can only guess is static build-up. It was weird to see it detected on the meter, but I am pretty certain that some Milli-volts of static potential would not be enough to set off the safety system for that. Nissan must have coding safe guards from something like that.

So I carefully put the service disconnect plug back in, bolt everything back together, snap the plastic cover back on the center, etc. My focus will be on the 12V battery now. I measure the voltage of the 12V battery since it's been disconnected from the Leaf for a while now. Low and behold, I seem to get a solid voltage reading of 12.62V. The weather is warmer now than it was in the morning, so maybe the 12V battery just appears to be ok?

Regardless, I'm going to hook a charger to the 12V battery and top it off before connecting it back to the Leaf. Since it appeared to be mostly dead before, I figured it was going to be a long wait to charge it back up before I re-connect it back to the Leaf. Nope, only took an hour to fully charge it.
Well I knew something was wrong then because I was using 1.5A charger and putting 1.5AH back into a battery rated for 43 AH in no way means that it was fully charged at that capacity. It just means the voltage might appear fine, but once a serious load is applied it will probably quickly fail.

So, I hooked it back into the Leaf anyway to see how it would perform. The voltage appeared to be much more stable now and I was about to clear out all the DTC issues with LeafSpy. I then shut it off, took a 15 minute break, came back to fire it up to see if any more DTC issues arise. Everything appeared to be fine now, not a single DTC, nice!

Final conclusion, I blame the 12V battery. Not that it's impossible that if the internal battery was touching the case somewhere, maybe the warmer temperature fixed that? I highly doubt that, so I think this dying 12V battery is making weird things happen. So, I talk with my relative about options, mainly about replacing this +5 year old Nissan OEM battery with something better. I could be wrong of course, but my next step is to do some load test on the 12V battery from various auto-shops to see what they think and finally I will do a full charge/discharge capacity test to see how much capacity the battery actually has. My guess would be it's so low as to be useless when actually called on to produce a lot of power for any extended amount of time. For now, they want to go the route of "please fix forever", so I'm going to have to do some research to see if I can find any 51R LiFePO4 size batteries (so I can drop-in replace it without having to do custom wiring), but not in the full AH size they don't really need 100AH of capacity for the Leaf but more like maybe 25AH to 30AH to avoid spending a fortune on it. For now, I told them I would not trust it drive around very far away if the 12V fails again and just leave the Leaf "on" and turn off all accessories if parked; if they need to run any errands until they get home and then shut it off at home just in case. I also left them my trickle charger and showed them how to keep the 12V battery topped off until a new replacement can be swapped.

At least I saved them a tow truck fee and Nissan diagnostic fee which could have probably resulted in the dealership charging them a fortune to replace the OEM 12V battery with another Nissan generic.

My next topic update will be when I can get a hold of that 12V battery, inspect it for damage or other issues and run it through more detailed testing of it's capacity.

 

[CaptLarry]

I will NEVER use some stupid Lithium battery to replace a Lead Acid in a vehicle designed to charge lead acid batteries.
The system is set up to properly charge a Lead Acid Battery... LiPos or whatever rando
thing you want to put in there.. has different charge voltage/current requirements. Clearly the computer is very sensitive to battery condition... It CAN and It WILL disable the car if it isn't
seeing the expected battery conditions.
The smart thing is to use an AGM Deep Cycle Sealed 12v battery.
The dumb thing is to think some Chinese BMS built into your lithium thingus is safe, adequate, compatible, or reliable. Unless you believe in fairies. then do it ~!