Timecapsule 2015, dodgy battery troubleshooting

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Dala

Well-known member
Leaf Supporting Member
Joined
Oct 28, 2018
Messages
464
Location
Finland
Hi all!
Just bought a leaf that is properly messed up. It only manages a measly 15miles (25km) range. I really need some help.

Spec wise, USA model, 2015, 24kWh, 12bars, 3k miles (5tkm) [I am located in Finland]

Car has had one cell repaired according to service logs, since it has been sitting for most of its lifetime.

So I bought it, thinking it was gonna be OK once the cell was repaired. Oh boi how naive.

The symptom:
So when I started driving it the first time, dash says 12/12bars and 100miles (155km) range. After driving 5miles, dash still reports 11/12bars. After another 5miles, the GOM starts dropping fast, and the bars aswell. After managing the measly 15 miles, GOM is down to 29miles left, 5/12bars and I seriously doubt it will manage another 5miles due to how rapid the GOM goes down. It takes away a mile every other second!

So i fastcharged it. Rinse repeat, same story. Here is how little the fastcharge added back to the car. 2.89kWh.
QhDqt8W.jpg


After the third fastcharge that day, the car went into turtle mode with full battery. Also the "check engine?" light came on.
eWVB6GR.jpg


Whatafaak, I thought turtle mode only was supposed to come on with low battery?

So I had to leave the car in the middle of nowhere, ordered a tow, gonna wait a few days to get it shipped back home.

Help! I am gonna try to get leafspy and check the codes and battery. But something seems so wrong, surely 15miles out of a car with only 3000 miles on it is wrong? Anything similar happened to someone here? I am kinda stuck with the car, since I bought it from a private seller :/
 
You almost certainly still have one or more bad cells in the car. The voltage in that one or more cells is dropping much faster than the other cells in the pack, causing the car to go into "turtle" mode even though the rest of the pack is almost fully charged. A battery pack is only as strong as its weakest cell and you have at least one VERY weak one. You need to use LeafSpy on the car, to show which and how many of them are bad.
 
I've read here that Turtle mode comes-on when any one of the cells drops down below a minimum voltage. It is completely independent of the amount of energy in the battery.

In the USA , we have a law called the "Lemon Law," which allows a car buyer to return the car if there is a serious problem. I don't know if Finland has any similar protection, but you may want to return the car, if possible.

If not, the battery should be under warranty until 2020: Google "2015 Nissan LEAF | Warranty Information Booklet". I think the dealer could see if the problem if they run a "cell pair test."
 
Yeah I am still waiting on the flatbed to deliver the car. Should be here sometime this week.

I also booked a service appointment for the car at the local Nissan dealership. Not feeling very hopeful about it. The time is next tuesday.

As soon as I get the car, I will try to look at the codes with leafspy, and also check the battery health.
 
The bad news continue, just received this email

"Nissan Nordic Europe Oy has not imported this vehicle therefore responsibility lies on selling dealer / importer. As Nissan Nordic Europe Oy has not imported this vehicle we don't know what has been done to this vehicle, where and how it has been serviced.
Vehicles that have been sold in Europe have Pan-European warranty, this vehicle doesn't.
Unfortunately we can't help you in this matter and offer goodwill. I suggest you to contact the selling dealer or the person who has imported this vehicle."

What the heck do I do now? :( :cry:
 
LeftieBiker said:
Does EU law allow for suing a seller for fraud if they seriously misrepresent the condition of a vehicle they sell?

In Finland it is very rare to sue someone. The buyers protection has many steps to rectify the purchase of an used car, which goes something
like this,
1. Talk to the seller. Work something out
2. Get an estimate for how much the repair will cost.
3. Ask seller to pitch in out of goodwill.
4. If not successful, then try to reverse the buy and refer to the law paragraphs etc.

Not a single mention of suing :) Main focus is on getting the car back on the road as fast as possible.

I got a call saying that the flatbed will arrive tomorrow morning, already got Leafspy pro and an OBD2 dongle, so expect some screenshots tomorrow :)
 
After trying 3 different ELM327, I finally found one that works!

Here are the results:
e7cH7IZ.jpg

MeBFusn.jpg

yafyswl.jpg

R2v6iyH.jpg


So it seems like the monkeys who replaced the cell in the car did not pre-balance it. Guess the next step is to open up the pack, and charge it manually up to 4.1V like the rest of them with a LI-ion CC/CV charger. Wow the Leafspy Pro is a great tool!
 
Dala said:
After trying 3 different ELM327, I finally found one that works!

Here are the results:
e7cH7IZ.jpg

MeBFusn.jpg

yafyswl.jpg

R2v6iyH.jpg


So it seems like the monkeys who replaced the cell in the car did not pre-balance it. Guess the next step is to open up the pack, and charge it manually up to 4.1V like the rest of them with a LI-ion CC/CV charger. Wow the Leafspy Pro is a great tool!
The weak cells (module) may charge to 4.1v but may not hold their charge under load, if you have any success let us know
BTW very low km's given the year and amount of charges, something funny there.
 
My guess is the two weak cells were not replaced. If they really were replaced, then they may get balanced by driving gently to get the other cells discharged as much as possible and then charging at a slow rate. It may take several charge/discharge cycles (at low charge/discharge rates) to get the pack balanced. I suggest driving as much as you dare and then running climate control until car shuts down (after parking in front of a charging station).
 
I too think it's more than the cells not having been pre-charged. I'd expect them to be closer to being charged by now - maybe 60% - and slowly improving.
 
Dala said:
So it seems like the monkeys who replaced the cell in the car did not pre-balance it. Guess the next step is to open up the pack, and charge it manually up to 4.1V like the rest of them with a LI-ion CC/CV charger. Wow the Leafspy Pro is a great tool!

No. Charge the car to full, and get a LeafSpy screenshot. Then drive the car and use climate controls right by the charging station to get down to near turtle again, and get another LeafSpy screenshot. Then charge the car to full again, get a third LeafSpy screenshot. Then with the car at or near full charge, wait a few days, get another LeafSpy screenshot.


Is it because the BMS or something else is always discharging these cells (57 and 58)? If so, then it might improve during a charge discharge cycle, but will get worse with time.

Or will it improve over a charge discharge cycle and stay that way (aka a "pre-balance" issue)? If so, then it might be fixable by just cycling.

Opening up the pack is something to approach with a lot of caution. Find out as much as you can first. Then make sure you have the correct tools and do things the correct way.
 
The guy I bought it from seemed to somehow think 25km range was acceptable for an EV. He had been using it in this state for a few months. Only with slowcharger, constantly topping it up to 100%. So I doubt it will get better with more cycles.

I have now personally racked up 6 charges, with range staying the same on each run.

There are some things I still wonder;
-When I picked up, he had the supposedly broken cell in a box. (no clue who replaced it)
-What if the replaced cells were preLizard? (or just not replaced at all)

I mostly lean on that the cell was replaced, but someone did a poor job of pre-balancing it. I also googled around, and it seems like hoping for it to balance out over time is a pipedream, taking several months due to the balancing circuits in this pack is just heaters, that barely pass any mA thru them

So I've decided to open the pack up. That way I can visually confirm that the cell is a lizard cell, and also try to bump it up manually. With no warranty I have nothing to loose. One of the reasons I sprung for a leaf is that it seems to be one of the few EVs that you can actually tinker with.

Stay tuned for pictures.
 
Question,
If someone actually installed one pre-lizard battery cell, would that mess up the charging?

I think I've seen some data that pre-lizard charged to 3.9V, and lizard batteries charged to 4.1xV Can anyone confirm this?
 
Lesson to learn... If a car has unusually low mileage it probably is because it was not drivable. I recently saw a several year old Leaf on ebay with only 100 miles on the clock... I would never touch that...

Also, Cars are sold AS-IS, this is the poster's burden, unfortunately.
 
Dala said:
Question,
If someone actually installed one pre-lizard battery cell, would that mess up the charging?

I think I've seen some data that pre-lizard charged to 3.9V, and lizard batteries charged to 4.1xV Can anyone confirm this?

The Gen1 (Canary, pre-lizard) cells charged to 4.0V. See here:
https://qnovo.com/inside-the-battery-of-a-nissan-leaf/

The maximum voltage at the pack is 2×4.2×48 = 403V, though it is widely known that the Leaf only uses about 80% of the pack’s capacity (20 kWh out of the 24 kWh to preserve cycle life) making the maximum cell voltage closer to 4.0V

I'm pretty sure that the voltage characteristics remain unchanged for ALL 24kWh battery packs. However, the voltage characteristics DID change for 30 & 40 kWh battery packs:
https://pushevs.com/2018/01/29/2018-nissan-leaf-battery-real-specs/

The maximum voltage remains roughly the same, but the discharge curve changes dramatically. A 30/40 kWh cell charged to 50% SOC will be at 3.6v, where 3.6v is nearly dead on an original 24kWh cell. This is one of the primary reasons you cannot install a higher capacity cells into a 24kWh pack--the old BMS will believe that it is nearly out of capacity when the pack is below 50% SOC.

So I'm pretty sure it should be theoretically possible to mix pre-lizard and lizard cells together in a single pack, but don't do it. This is because there are likely to be subtle differences between the discharge curve that would cause significant BMS shunting and lower range. It'll also become a big issue as the pack ages because the pre-lizard cells will likely age more quickly and thus you'll end up with an unbalanced pack.

Who did the cell replacement? Was it Nissan or a 3rd party? If it was Nissan, I'd take it back to them and tell them it's covered under warranty and should be fixed. The pack has both a 60k mile, 5 year capacity warranty, and an 8 year failure warranty. I would get them to fix the car. if you (or a 3rd party) open it up and start messing with it, they'll rightly claim that it's no longer warrantied. Note: If the battery was stored at zero or near zero SOC for more than 14 days, it may not be warrantied anyway:
https://www.greencarreports.com/news/1073334_nissan-leaf-battery-warranty-what-you-must-do-to-keep-it-valid
 
So I started taking it apart.

Got it into the garage, was a wet day
gICey9v.jpg


Disconnected the 12V battery
WbuV0eH.jpg


Found the fuse
2AOcA6z.jpg


Disconnected the fuse, gonna stick to HV gloves each time i'm remotely near orange cabling
GKGcC7Y.jpg


Started propping up the car high
kHh4xxP.jpg


Removed splash plates
rKj3L4Q.jpg


Found the battery connections and CAN cabling, disconnected them
2WdC7TG.jpg


Put pressure on battery, started loosening bolts
3tpzdam.jpg


Built a dolly to be able to slide the pack around
v42e3Z7.jpg


Lowered battery onto dolly
qN4h1rn.jpg


Battery out
CQvyI8B.jpg


Started to pry the glue apart
8tsiBci.jpg


Cover off
SUzFU25.jpg
 
So yesterday I started the charging process. Decided to take it slow due to not knowing much about the Li-MnO2 cells (I'm more of an 18650 guy)

Since the cellpair 57&58 was at the absolute bottom of the stack, they will be extremely hard to get to. I don't want to dissassemble the pack, so I improvised some sticky leads with harddrive magnets inside alligator clips. That way I can just lower them down into the pack, and they will stick to the terminals.
0RLVMMH.jpg


I then hooked up a bench supply, set it to 8.4V and connected it to the outer terminals of the 2S cell. I am lucky that the rest of the pack is at 4.00V cell average, so I wont have to worry about CC/CV switchover, just CC charging up to 4V (8V effective due to 2S). As charge current limiter, I set it to 0.3Amps, to keep temps and everything nice and smooth.
qhiNijT.jpg


I also disconnected some of the BMS leads, don't know if this was necessary, hope I don't break the BMS by piggyback charging this way.

After 18h of charging, the cells are up from 3.60V -> 3.95V, so just a few more mV to go!
 
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