2014 nissan leaf high voltage battery.

[otsija86]

Hey, i have question about 2014 leaf high voltage battery.

1. High voltage BMS always balances 0,5A per cell battery, even if car is turned off, it was true or not? Under this current is safe charge car hv battery directly hv pins?

2. High voltage battery negative terminal, it was isolated car body and 12V battery negative terminal or it was connected together?

3. High voltage battery data connector, what this pin-s doings there? If some cell is overvoltage or undervoltage, can i take a signal somewhere there and drive my solar panel controller and turn it off when battery is fully charged or turn off load power when battery is too low and bms send shutdown command car or something? And maybe i can take this signal there too? (s0rry 0-level english)

 

[nlspace]

Hey, i have question about 2014 leaf high voltage battery.

1. High voltage BMS always balances 0,5A per cell battery, even if car is turned off, it was true or not? Under this current is safe charge car hv battery directly hv pins?

2. High voltage battery negative terminal, it was isolated car body and 12V battery negative terminal or it was connected together?

3. High voltage battery data connector, what this pin-s doings there? If some cell is overvoltage or undervoltage, can i take a signal somewhere there and drive my solar panel controller and turn it off when battery is fully charged or turn off load power when battery is too low and bms send shutdown command car or something? And maybe i can take this signal there too? (s0rry 0-level english)

Howdy and welcome to the forum, where are you located?

1. The balancing current is only 10mA (0.010 A) per cell, and this is a bleed-off current to lower the voltage of a cell that is too high. The balancing is done while plugged in to charge, but it may have been reported to also occur at other times when the car is OFF.

2. The pack is isolated from the car chassis; chassis is only connected to the 12V negative.

3. Are you talking about the round connector into the Pack, or the multiple connectors with wires from each cell into the Lithium Battery Controller (LBC)? The LBC wires are inside the pack and are used to measure and balance the cells. This diagram may help show the connections of the round connector.

 

[otsija86]

Hey, i m from east europe, i have one old 24kWh leaf here, battery health is 70%(old and i want safe charge) and I think it would be a cool project add roof 200W solar panels and charge directly high voltage battery. I've been experimenting here 18V solar panel to 300-400V DC fully isolated converter and it looks work well 90% efficiency. 10mA is low balancing current per cell, then is still some risk if i put 400V and 0,5A uncontrolled power directly there? I mean this big power cable, connecting there some tiny cables(adding fuses and then moving trunk this cables). And data connector i mean this https://evsenhanced.com/wp-content/uploads/2020/07/BattCompareBlankwconn2236v6-768x368.jpg battery outside round connector, maybe there some pins send some signal to car or something, when some cell voltage is too high or too low and i can use this ?

 

[nlspace]

Do you have a whole car, or is this for just a main battery pack?

 

[otsija86]

I have a car, but i want add some flexible panels roof and charge directly hv battery. If i cant take some useful signal data connector, how bad idea is then just push 200W power directly battery? I see that youtube videos some people doing that https://www.youtube.com/watch?v=UcGoSO_uRXs .

 

[nlspace]

Might want to take a look at some other videos and pictures of range extenders too,
leaf range extenders

 

[otsija86]

I know it can be dangerous, thats why i try find more information this data connector pins and what information moving there. Or maybe somebody know other forum, where i can find maybe this hv battery data connector information?

 

[nlspace]

Did you not see the diagram i posted? Look at connector LB1, the pin numbers are shown for the wires going into the Lithium battery. Data is sent over the CAN buss. What are you looking for?

 

[otsija86]

Yes i see it but i am not sure if i can find out everything what i need. If all this data runs through this canbus language, then I can't just take that overvoltage / undervoltage signal from there? There are a lot of pins and i was hoping that maybe there is an overvoltage / undervoltage(or something) directly analog signal there what i can use easily.

 

[nlspace]

All the data is digital over the CAN buss, there are no analog data signals such as you are looking.

Inside the pack is the LBC which measures the 96 cell voltages and reports the data to the VCM over the CAN buss.

 

[otsija86]

Okey, thats bad news. if anyone has a good idea how to get this bms error signal it can publish it, but probably this plan was out now :/. The only idea at the moment is to set a voltage limit 4V per cell (384V) and not charge higher voltage output directly for HV battery. There is risk that some element error can be dangerous, but how big that risk is?