Bars vs LeafSpy "weak cells"

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khbkhb

New member
Joined
Jun 20, 2022
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3
Looking at a used 2017 Leaf S, there are 10/12 bars which isn't bad ... but using LeafSpy SOH is 74%, and cells 1, 3, 5, 20, 24, 25, 27, 33,36, 39, 41, 43, 79, 81 and at least one more show up as "weak cells" during our short test drive. The pack wasn't fully charged before our test ride (LS says 94.6% SoC). Just how bad is this? Anyone have any luck with taking a used leaf with such a pack to a dealer for a factory replacement or does the warranty only start kicking in at 8/12 bars or some catastrophic failure?
 
First off, anything ~95% SoC should be considered "fully charged".
You don't specify the size of the pack, but with a 2017 I'm going to assume 30kWh...which are known to be problematic. A warranty replacement is only triggered by 8 capacity bars...or something much more catastrophic than a few "weak cells" (requiring a cell-level test).
You simply need to determine if the range and cost (you didn't mention the latter) is attractive at this time.
 
First off, you don't need to specify the pack on a 2017 since there was only one option.

You didn't mention the mileage? You realize you can get a replacement pack free if less than 100,000 miles or 8 years? That gives you time to lose those few bars and kinda sounds like you might be dropping #3 relatively soon.

FYI: replacement WILL BE a 40 kwh.
 
Some people have gotten new packs because of bad cells, but they have to be bad enough to cause the car to shut down, or at least enter "Turtle" mode, and they also have to cause hard error codes to appear. Dealers are also very reluctant to go that route, even with cars that clearly qualify for the cell defect warranty.
 
LeftieBiker said:
Some people have gotten new packs because of bad cells, but they have to be bad enough to cause the car to shut down, or at least enter "Turtle" mode, and they also have to cause hard error codes to appear. Dealers are also very reluctant to go that route, even with cars that clearly qualify for the cell defect warranty.

Too true. One LEAFer took it another step by capturing video evidence of the issues he was having as the shop when they claimed it could not reproduce the issue. After seeing the video evidence, the tech did a ride along with the customer and sure enough, took less than 10 miles for it to happen. He was going from 50% SOC to turtle in that time on a 40 kwh pack.

My thought; The shop isn't road testing these cars. Simply running a scan and everything is fine...when the car isn't moving
 
... using LeafSpy SOH is 74%, and cells 1, 3, 5, 20, 24, 25, 27, 33,36, 39, 41, 43, 79, 81 and at least one more show up as "weak cells" during our short test drive...

What mV spread was showing for those weak cells? A small mV spread among cells is normal, especially if the pack hasn't recently been charge to 100% SOC. If some/all of those cells are substantially lower than the rest of the pack, I would walk away unless you want to try for the replacement pack lottery.
 
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