Hi! And potential new owner question

Hello everyone

I am on the train about to go and look at a leaf and requested the dealer sent me some leaf spy data. I have just received it and although the soh is showing as 97% at 47% soc one cell is significantly lower than the rest - 3.70v rather than 3.75 and showing as blue also.

Apologies for the ignorance but my question is basically is this a fatal issue which should trigger me to either heavily negotiate / walk away or will the bms perform some magic to resolve this after a period of time?

Thanks in advance!
Rob

Here is a screenshot if it works

OK, link to drive! https://drive.google.com/file/d/10Nm2zicLXsJP_gBwwwoa4_pYz_oRsNFR/view?usp=drivesdk

It's not good. I don't know enough about bad cells to know if this might be balance-able, or if it's definitely a bad cell. I don't like that the rest of the pack looks reasonably well balanced. Someone should have an answer of more use shortly.

I think it's a bad module. To me, that's too big an imbalance for that % SoC. I can't recall a time I've seen an imbalance on my Leaf that large, esp. at that high an SoC.

Can you get a Nissan dealer to replace the bad module under warranty? Google site:mynissanleaf.com cvli for more threads on this.

http://www.mynissanleaf.com/viewtopic.php?p=457982#p457982 was an example where the new owner BiggieJohn was successful in getting his dealer to fix it. The previous driver, JeremyW didn't have such luck.

I would go look at the car in person and look at the cell voltage graph with the car in READY mode. Since the screenshot shows 0 miles on the odometer, it was taken without having the car in ready mode so the cell voltage data is not accurate. If the readings are confirmed with the car in ready mode, then I would consider that cell pair to be somewhat weak. It is not bad enough yet to get Nissan to do anything under warranty.

Thanks all.

So I just viewed the car and walked away, for now. The car was fully charged and in ready mode and showed a variance of 48mv (from 68mv yesterday) so it was heading in the right direction. I said to the dealer if he can show it having a variance of 25 or less after a few cycles of use then I'd definitely be interested.

Does that sound like the right thing to do?

Thanks!

LeafRob said:

Thanks all.

So I just viewed the car and walked away, for now. The car was fully charged and in ready mode and showed a variance of 48mv (from 68mv yesterday) so it was heading in the right direction. I said to the dealer if he can show it having a variance of 25 or less after a few cycles of use then I'd definitely be interested.

Does that sound like the right thing to do?

Thanks!

Click to expand...

Good job in my opinion. Shows the dealer you are concerned about the battery, the single most important part of an EV and the one that Nissan, again in my opinion, has really not stepped up to the plate. You are likely also educating the dealership that (a) not all buyers are stupid, (b) the traditional knowledge that they have about vehicles has to broaden for EV’s, and (3) in a perfect world the dealership or Nissan would fix such issues before trying to foist the car onto someone who is buying a very likely problem. If this happens enough, i.e., not being able to sell a vehicle with such an issue or having to discount it heavily, there is an infinitesimal but greater than zero chance it could change things upstream with Nissan and their hands-off approach to battery issues and service. It is a bit like trying to sell a car with a V-6 engine, one of the pistons of which is missing.

Side note: I tried to use the letters a, b, and c above but putting the c in parenthesis reverted it to © every time. So the new math is a, b, and 3.
Oh dear Lord, where is that coffee this morning?

Thanks for the reply!

Now I understand leaf spy after watching bids all day this screenshot may also be handy, note the soc and gids are close, but the dte is waaaaaayyyy down!

https://drive.google.com/file/d/10eUAnQmEz095JRoyNTOII5kH7tZggHsQ/view?usp=drivesdk

I take it this is down to the dodgy cell and is a bad sign?! Is this recoverable by the bms?

Thanks

LeafRob said:

Thanks for the reply!

Now I understand leaf spy after watching bids all day this screenshot may also be handy, note the soc and gids are close, but the dte is waaaaaayyyy down!

https://drive.google.com/file/d/10eUAnQmEz095JRoyNTOII5kH7tZggHsQ/view?usp=drivesdk

I take it this is down to the dodgy cell and is a bad sign?! Is this recoverable by the bms?

Thanks

Click to expand...

You need to look at the cell voltage display to see cell balance and SOH. The display you referenced looks normal for a battery that is about 50% charged.

Hi,

I think that may have been my first attachment earlier in the post (apologies, I can't get the images to show on the posts).

It showed 1cell way out at around 50% soc, with a 62mv difference.

Does that shed some more light?

Thanks

The way it stands now, the car appears (strongly) to have one weak cell and also maybe one slightly weak cell. Unless they are willing to replace the worse one, I'd pass.

LeafRob said:

I take it this is down to the dodgy cell and is a bad sign?! Is this recoverable by the bms?

Click to expand...

It is recoverable only by the dealership replacing the dodgy cell prior to selling it to you or anyone else. Make that a condition of the sale, and offer whatever you were going to offer less a "customer-concerned-about-the-dealer-negotiating-in-bad-faith" discount of, say, another $500 or so.