Mismatch of SOC values ZOE battery GEN1

[valentzoe]

Expected Behavior

The SOC calculation requires a significant correction for Battery ZOE GEN1.

Actual Behavior

I noticed that the SOC calculated by the emulator is: -70% and the real SOC is 93%, -20% and the real SOC is 55%, etc. On the photo: charge-discharge curves of real Li-Ion, NMC 36 Ah.

• Software version: 7.5
• Battery used: Renault ZOE GEN1
• Inverter communication protocol: CAN
• Hardware used for Battery-Emulator: HW_LILYGO
• CONTACTOR_CONTROL: yes
• DUAL_CAN: no
• WEBSERVER: yes
• MQTT: no

[dalathegreat]

We use the SOC% sent by battery, does this mean that the battery itself is not sending the correct SOC% when discharging?

[valentzoe]

Hi! Probably not. It probably sends this data to the ECU ZOE. Here is a picture.

[valentzoe]

[dalathegreat]

What is the lowest you can discharge the battery to?

[valentzoe]

Did as you requested today and discharged it until it was completely cut off by the inverter. And this is what I got.

[valentzoe]

I discharged the battery at your request. And this is what I got:

[dalathegreat]

Okay so at 20% SOC left the voltage was 3600mV/cell. This sounds like quite common thing on EVs, on the Nissan LEAF it is not normal to go under 3500mV/cell, there is barely any capacity left there

I suggest removing the "Rescale SOC%" setting, and trying to use the battery all the way down to 0-5%. This should correspond with anywhere between 3000-3500mV. Do note that the furthest discharge point is also based on temperate, and SOH%. I really dont think we have any bug here.