• close and put back the battery

    mb0dm3r01/17/2021 at 16:30 0 comments

    Using the dismantiling guide again, I've put back the battery. A bunch of work again, sweating. But finally the car works and charges again, like new!

  • test replaced board

    mb0dm3r01/17/2021 at 16:28 0 comments

    I've attached all the cables of the battery to the car, except the orange high voltage cables. This allowed to test the BMU and observe the cell voltages using OVMS again.

    Be aware, this triggered an airbag warning, wich needs to be reset by the garage. The warning is due to powering the car (attach the 12V battery) with disconnected airbags. The airbags are disconnected because I've taken out the drivers seat to gain access to the HV plug of the battery.

  • fix BMU

    mb0dm3r01/17/2021 at 16:25 0 comments

    I've actually had the plan to replace the LTC6802, but unfortunately it had a very small pin pitch and I am not so good at soldering. That's why I've odered some secondhand BMU PCBs found on Ebay. They unfortunately did not have the correct ID (01 and 12, I need 06) that's why I've decided to move the EEPROM from the original PCB to a new one.

    On this occasion I've pulled a dump of each EEPROM using an Minipro EEPROM reader. See the *.srec files in the project documentation.

  • Take down battery

    mb0dm3r01/17/2021 at 16:20 0 comments

    It would  be easiest to use a car lift to take down the battery, unfortunately I don't have access to one. So I've helped myself using stacked euro pallets and a forklift. The Mitsubishi dismantiling guide I've found on the internet also helped a lot to take down the battery. It's quite some hours of work.

  • diagnostics and research

    mb0dm3r01/17/2021 at 15:32 0 comments

    First I've installed an OVMS (https://www.openvehicles.com ), which has a great diagnostic interface for the BMS. There, I could see the voltages of all 4 cells of BMU6 floating around, having values clearly out of any sensible range. If this happens too long the BMU will issue an error and hence charging will be stpped.

    Having researched online I've found others also have similar problems. There are some good threads in forums:

    There I've found some schematics and pictures of the BMS PCB, showing the IC LTC6802, looking up the datasheet reveals it's a battery cell monitor. Thats's probably the defective chip.

    In some forums I've found great schematics of the iMIEV's battery. They later helped me a lot.