Tips

Tips for using the BMS

Low profile connector on prismatic cell boards

The negative and positive end cell boards normally include a right angle, 2-pin connector. This connector extends above the barrel of the ring terminal, making it the tallest component. In applications where that is a problem, you may move the connector off the board, so that it sits lower and it no longer cause an interference.

Cell board connector off the board.

Having the connector off the board is not as secure, so adding some epoxy may be a good idea.

Alternatively, you may want to consider using 2 short wires to move the connector offthe board all together.

Performing an isolation test on request

A Lithiumate with HVFE can be configured to perform a test of the pack's isolation from chassis just before turning on the contactors.

This test has some limitations: it is only performed once before turing on, and it lasts just 10 ms, which will make it fail if there is a significant capacitance between the battery terminals and chassis.

An external controller can force the HVFE to perform an isolation test through PID messages on the CAN bus, at any time, and make it last as long as required to charge up the capacitance between the battery terminals and the chassis.

To do so, follow the steps listed in the table "To test pack isolation, contactors off" on the 3rd sheet of the PID list spreadsheet.

Backing-up and retrieving settings

For older rev BMS controllers (Rev 0.96 and older), you can use a programmer and a Windows computer to read and write the settings from your distributed BMS' EEPROM. (Newer BMS controllers have a built in back-up function, so there's no need for a programmer to do a back-up.) This can be useful as a back-up, or to quickly duplicate settings from one BMS controller to others.

• Get a PicKit II programmer
• Install the PICkit 2 software on the Windows computer
• Prepare a programmer adapter cable
• Connect the programmer to the BMS controller with the adapter cable
  • programmer side: 6 pin connector, yellow wire on pin marked by a triangle
  • BMS controlelr side: 5 pin connector, red wire in pin 1 (closest to white connector)

PICKit 2 programmer connected

• Run the PICKit 2 application

Uncheck the "Enabled" checkbox below the "Program memory" label. If you don't, you'll erase the entire memory, and you'll make the BMS controller useless.

PICKit 2 programmer window

• MAKE SURE THAT THE "Enabled" CHECKBOX BELOW THE "Program memory" LABEL IS UNCHECKED!
• Make sure you see the text "Write and read EEPROM data only", in red, towards the bottom
• Click the "READ" button to read the EEPROM contents
• Click the "Read device and export" button to read the EEPROM contents, then save it to a file, naming it something like "back-up.hex"
• Select the "File / Import Hex" menu to open a previously stored hex file with settings, and load it
• Click the "Write" button to write the data into the EEPROM
• Note that the box at the bottom of the window shows the EEPROM contents, as read, or as about to be written