[kennybobby]

Nissan uses "LBC" as the term for what almost everyone else calls a BMS.

This thread will be a placeholder for electrical schematics and details for a Gen 1 unit, there are 4 "Types" identified in the Factory Service Manual (FSM). Types 1 and 3 have no pack heater, whereas 2 and 4 do have heaters. The difference is related to the Service Disconnect device.

Maybe some firmware, or it might have it's own thread depending upon what breaks loose.

There is an eeprom that i suspect contains VIN related info, but haven't read the contents yet.

Please start a separate thread to discuss problems, troubleshooting and repair activities--trying to keep this thread focused on just the tech info and discussion of the circuits, etc.

INDEX to go here.
Reserving a couple of spots for schematics, to be added as available. i may post the hand drawn and later sketch them up with kicad.'

 

[kennybobby]

reserved for schematics

i know these are crude but they will be replaced with kicad sketches as i get them drawn up.

Power supply trace notes

Insulation Resistance Check Circuit trace notes

 

[kennybobby]

reserve for photos too

 

[kennybobby]

Power Supplies and Connector Overview:

There are three 12VDC power feeds into the LBC low voltage side on connector LB11 which plugs in to CONN1 on the pcb. This is on pins 5,6 and 12, where pin 1 is in the upper left corner when looking into the right-angle header soldered and screwed to the board.

CONN2 is also on the low voltage side holding wiring for the 4 temperature sensors.

Along the bottom edge are 4 connectors for the high voltage section, the cell taps are routed to these on LB13-16.

 

[kennybobby]

The board was built by Calsonic Kansei, and likely designed by NEC Energy Devices. i'm finding a few problems with reversing this board:

1. The board is coated with a hard brittle clear coat that must be removed to make any measurements, trace out circuits and vias, or read marking codes, etc. It is tedious and time consuming to remove the coating without damaging solder junctions, pins and components.

2. Several chips have been etched to remove the marking code, so it is difficult to determine the device and function.

3. There are 25 BMS chips on the board, 24 used for the cell voltages and 1 for insulation check, etc. These chips are marked NEC D15110, but don't seem to have any data sheets information available. One website identifies these as Analog Front End chips that interface with the micro controller, IC1, which appears to be an NEC/Renesas V850ES/FG2 processor, μPD70F3236(A). There are 2 sets of empty connector locations marked CONNFLASH and TARM1 likely used for programming as the traces run to IC1.

 

[zepol_wube]

You should check out

WolfTronix

I suspect they have a lot of the information you seek.
Here is a starting point to trace back from

He has reprogrammed, rewired, and repurposed the Nissan Leaf BMS systems

 

[kennybobby]

Thank you, i had not seen his progress in some time. His board is a different version from the one i'm reversing, e.g. no Insulation resistance check circuits are populated on Wolf's board, and neither are those related to the pack heater (the Type 2 or 4 versions have pack heaters).

i think his pack is a newer version from a late model 2013 or early 2014 since the main power casting was made in May 2013, and the B24 connector has 35 pins instead of 22.

 

[zepol_wube]

For as cheap as you can find a 2013 BMS it may be worth your time to get a newer one and build off his work rather than start again? We have extensively copied his work to create lopified.blogspot.com. We used all 48 modules as when we had started he had not yet figured out how to reduce the module count. Pulling out 4 modules sure would have been a time saver.

 

[kennybobby]

That's an interesting blog, looks like i have alot to read and videos to watch, to get up to speed on all this work.

My motivation with this board is to troubleshoot a fault of the Insulation Resistance sensing that is throwing DTCs in the OEM cars. There have been several reported on the laef forum recently and wanted to determine if the LBC could throw false flag or if insulation is breaking down. How is the measurement made, what does it really measure, what does it mean, etc.

The extra D15110 chip, IC38, is powered from cells 93-96, and it is reading the pack voltage on pin 11 thru a resistor divider network. It seems that the μcontroller can drive 5V into the top of the 3 electrolytic caps (in series to bottom of pack) thru two paths with different time constants (0.45 and 2.25 s). Optocoupler PC5 is used to turn ON IC38 but i haven't traced what does that yet.

Do you have a pinout for the D15110/15120 chips, or know what they are, has anyone figured that out yet?

 

[zepol_wube]

We did not need to alter our BMS internally at all. We rewired our pack to look identical to the BMS and use the standard BMS pack outputs to inform our monitoring systems. The BMS does everything autonomously, we tell it nothing. I do not know how Wolftronix is set up to share information about schematics or the financials of his business, you can see from his videos that he is willing to share knowledge.