The 40KWH Battery Topic

[LeftieBiker]

The histogram visually represents both the voltages of each module, and the differences between them. That "25mv" means that your cells, even though they look awful in the histogram, are pretty close together in voltage and capacity. The red just means that they were receiving charge at the moment the reading was taken. Don't worry about them unless you get odd symptoms at low states of charge. If so, take another reading at 10-20% charge

 

[cwerdna]

Not sure if anyone posted this already but https://medium.com/@eTaxidriver/aná...l-nissan-leaf-40-kwh-tras-5-años-d2080401ce1e is from Sept 26, 2023 of 40 kWh Leaf taxis in Spain. Unfortunately, it's in Spanish but you can have your browser or Google Translate translate for you.

There is a mention of this (translated):
"The only car in the study that had already lost two bars. Outside of the study we have 3 colleagues who have lost 2 bars, most around 180,000km."

 

[Bombastinator2]

Not sure if anyone posted this already but https://medium.com/@eTaxidriver/análisis-de-las-baterías-del-nissan-leaf-40-kwh-tras-5-años-d2080401ce1e is from Sept 26, 2023 of 40 kWh Leaf taxis in Spain. Unfortunately, it's in Spanish but you can have your browser or Google Translate translate for you.

There is a mention of this (translated):
"The only car in the study that had already lost two bars. Outside of the study we have 3 colleagues who have lost 2 bars, most around 180,000km."

So Spanish Spanish rather than Mexican spains? Iirc they read the same, though Spaniards sound like they’re lisping

 

[leafthesis]

Long shot, does anyone know what the name of the connector connecting the battery and the inverter? The complete harness has item number 297A6-5SA1A, but I'm looking for the name of only the connector connecting to the battery.

For example, the connectors and harness is seen here: https://www.ebay.com/itm/195804984466

 

[Bombastinator2]

Long shot, does anyone know what the name of the connector connecting the battery and the inverter? The complete harness has item number 297A6-5SA1A, but I'm looking for the name of only the connector connecting to the battery.

For example, the connectors and harness is seen here: https://www.ebay.com/itm/195804984466

“Battery cable”? More than 1 part, generally.

 

[leafthesis]

“Battery cable”? More than 1 part, generally.

Yeah, I found only the harness so far. I guess you're right, they only sell them in a package.

Another question if someone's into standalone use of the 40 kWh battery. I have only the battery (not the full car, so no VCM etc.) and I'm trying to get the BMS to balance the cells, but it won't do it. I read on many forums that the "Nissan Leaf 40kWh BMS is actively balancing the cells all the time, even during charging", however this doesn't seem to be the case for me. I'm reading the values off the CAN-bus on 0x7BB, which allegedely reports the status of the balancing resistors, but all the bits are 0s, confirming my suspicion that the BMS is not doing any balancing.

I'm wondering if somehow it refuses to do balancing if it can't communicate with the VCM? Maybe there's way to force the BMS to start balancing by sending some CAN-bus messages? Glad to hear any suggestions for what to try.

 

[Ronin78PL]

Hello community, I'm writing from Poland. I would like to show you the results of my car, which I have been driving since new, and ask whether I fit into the statistical average for the SOH Leaf 40? The car is 10 months old (10.000 mil / 16.500 km) and the average energy consumption over the entire distance is 13.1 kWh/100 km

 

[Bombastinator2]

Yeah, I found only the harness so far. I guess you're right, they only sell them in a package.

Another question if someone's into standalone use of the 40 kWh battery. I have only the battery (not the full car, so no VCM etc.) and I'm trying to get the BMS to balance the cells, but it won't do it. I read on many forums that the "Nissan Leaf 40kWh BMS is actively balancing the cells all the time, even during charging", however this doesn't seem to be the case for me. I'm reading the values off the CAN-bus on 0x7BB, which allegedely reports the status of the balancing resistors, but all the bits are 0s, confirming my suspicion that the BMS is not doing any balancing.

I'm wondering if somehow it refuses to do balancing if it can't communicate with the VCM? Maybe there's way to force the BMS to start balancing by sending some CAN-bus messages? Glad to hear any suggestions for what to try.

If it’s a bare battery you’re likely using it as a powerwall or something and it is likely something someone already pulled out of a car because it had problems. No telling what.

 

[leafthesis]

If it’s a bare battery you’re likely using it as a powerwall or something and it is likely something someone already pulled out of a car because it had problems. No telling what.

Thank you for your reply, I was actually about to give an update myself as I figured it out.

I was working on the reassembly and hadn't properly fixed the BMS to the battery structure. This probably resulted in the BMS reporting insulation-error and subsequently it goes into protection mode and stops all balancing (thanks to Wolf Tronix and his excellent Youtube-videos debugging the balancing chips).

After I secured the BMS properly everything works as expected!