BMS Ready for Deployment
I now have four (4) BMS units built up and tested and ready for deployment I machined the front panels for the CINCH enclosures to fit the DB25 and M12 round connectors. Below is an image of the four units. I still need to make up more M12 cable sets, to connect all four units together in the car. I have the shielded cable, just need to get more M12 connectors. Just like any electronic component the connectors go out of stock at Digi key and then I have to find an alternative source. I also have to make up DB25 cables to connect the BMS units to the batteries. All batteries have the DB25 connector that was used to connect the DC2260A BMS demo board to measure the cell voltages, one battery at a time. Now the cell voltages of at least the first four batteries can be monitored together, at the same time. The BMS units will be mounted on the side of the battery box and none of the battery DB25 cables can reach that, so new cables need to be fabricated. I think connecting to the existing DB25 cables would be better for testing than creating a cable that goes between the BMS and the BMS connections on each battery.
I have to use a different enclosure for the first BMS PCAs that I built up. At that time, I was not sure the Arduino Nano Every processor board should be directly soldered to the BMS PCA. The Nano is connected via SIP connectors on the bottom side of the PCA, so that it can be removed, if necessary. I have three PCAs that were assembled that way. That extra 3/8" of height means the PCA cannot fit in the CINCH enclosure. I will be using a plastic enclosure made by Jameco. See the image below. You can see the SIP connectors on the bottom side and see how much that offsets the Nano from the PCA. The PCA has standoffs in the corners to raise the board to the correct height for the DB25 connector. You can see in the image how the front of the enclosure is machined to fit the DB25. The side of enclosure, opposite the DB25 side will have the circular M12 connectors (not yet machined). These BMS units will be connected to the batteries under the rear seat, so they will be inside the passenger compartment. The Jameco enclosure does come with a gasket for the lid. Not as moisture tight as the CINCH enclosure but should be good enough inside the car.
