Lothsahn
Posts: 550
Joined: Thu Apr 05, 2018 4:35 pm
Delivery Date: 04 Jan 2018
Leaf Number: 007797

Re: Leaf range after battery module replacement

Thu Oct 17, 2019 9:56 am

On a 2011, the CVLI (Cell Voltage Loss Inspection) test requires that the battery be at 3.712v or less to work. That corresponds to approximately a 7% SOC for a 24 kWh battery pack. See here: https://pushevs.com/2018/01/29/2018-nis ... eal-specs/ (The graph is near the bottom of the post, above the comments. Do not look at the top graph--that's for a different chemistry).

I don't know what % is required for the 2018, but if the dealer didn't drain the car to approximately a 7% SOC, the CVLI test cannot be performed. If they just looked at your car and said "It's not throwing any codes", that's not sufficient. The car's BMS (battery management system) may throw a code at higher voltage levels, but without a CVLI test, you cannot rule out a mismatched or bad cell. A full CVLI must be performed to know for sure that cells are good and balanced. You know, via LeafSpy, that yours are not. The trick is getting their tools to indicate a code so they stop arguing that your car is OK.

From the service manual:
P33E6 CELL VOLTAGE DEVIATION DIAG
1.CHECK SELF-DIAGNOSIS RESULTS OF LI-ION BATTERY CONTROLLER
2.CHECK FREEZE FRAME DATA (FFD)
3.PERFORM CELL VOLTAGE LOSS INSPECTION
4.DISCHARGE OF LI-ION BATTERY
(essentially turn on the high beams, heater to full, AC to full, defrost, etc)
Check “DATA MONITOR” and let the Li-ion battery discharge until the “MINIMUM CELL VOLTAGE”
reaches 3,712 mV or less.[/b]
5.CHECK CELL OF VOLTAGE LOSS


I would also ask if they performed the module charge balance, as required in the service manual, when replacing your cells. That specifically says to balance the charge voltage of the cells with a module charge balancer.

From the service manual:
MODULE CHARGE BALANCE
1.CHECK ADJUSTMENT VOLTAGE VALUE
2.CHECK MODULE VOLTAGE
3.DISCAHRGE OF MODULE VOLTAGE (spelling intentional--it's wrong in the service manual)
4.ADJUST VOLTAGE WITH A MODULE CHARGE BALANCER
5.CHECK MODULE VOLTAGE
6.CHECK CELL VOLTAGE
2011 Silver SV, purchased 2018, lives in Missouri (previously in CA)
LeafSpy Pro + BAFX Products OBDII dongle
Battery swap 2019/04/24 (87% SOH, 12 bar)

GerryAZ
Gold Member
Posts: 2297
Joined: Mon Nov 22, 2010 6:47 pm
Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: Leaf range after battery module replacement

Thu Oct 17, 2019 11:57 pm

Don't count on the car failing the CVLI test even at or below VLBW. My 2015 had several weak cells that were rapidly getting worse (all located at the front of the pack if cell numbers in Leaf Spy match service manual). Leaf Spy performs the CVLI calculations when battery voltage is low enough and it would flag some or all of those cells as weak under certain SOC conditions, but show them as normal at other SOC levels. In particular, the cells would be flagged as weak near VLBW, but show as normal after further discharge. The car never set DTCs related to this issue even though I drove as much as a mile after Turtle to get to a charging station a few times.
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015; traded 8/10/2019 at 82,436 miles
White LEAF 2019 SL+ purchased 8/10/2019

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