Brusa

Installing and programming a Brusa charger with a Lithiumate BMS.

The Elithion BMS is compatible with a Brusa charger out of the box. But a Brusa charger needs to be programmed to work with a BMS.

Brusa NLG5 wiring (pdf)

• A simple terminal application is sufficient to monitor the Brusa operation (password is "MONITOR")
• To program the Brusa, you need to install the ChargeStar application on your laptop
• ChargeStar can only work out of COM1 port, so you'll need to reassign the com port you're using to be COM1, using your Window computer's Device Manager
• Unless you specified "CAN mode" when ordering the charger, out of the box the charger is set for Automatic Mode (stand-alone charger); you'll want to reprogram it to CAN mode to work seamlessly with the BMS
• Program the max output voltage high enough so that it doesn't interfere with the BMS
  • The BMS controls the voltage, but only up to the max voltage setting in the charger
  • You will want to set the charger above the max pack voltage
  • The charger has a 1% tolerance, so if you set it just 1 V above the max pack voltage it may stop charging too soon
  • There are 2 approaches, based on what you want to achieve:
    • If all you want to do is limit the charger voltage in case of open circuit, then set the charger max voltage at some 30 V above the max pack voltage
    • If you want a backup safety measure in case the BMS doesn't control the charger, then program the charger for the max pack voltage; then, measure the unloaded output of the charger and tweak the voltage setting to actually get the desired voltage
• Out of the box, the charger is set to look at a thermistor (out of a possible 3 thermistors); if you don't use any thermistor, you'll want to turn that test off

Some troubleshooting hints:

• Is the HLIM LED on the BMS controller lit?
• Is the FLT LED on the BMS controller lit?
• Any errors in the Brusa Monitor display?
  • "SDT Batt VoltHi: ERR" error: check the can settings operation mode: "Switch off immetiately if: / Battery voltage above"; Set that value ot about 25 % more than the max pack voltage
• Are there exactly 2 terminations on the CAN bus, physically at the farthest 2 points of the bus?
  • The Brusa doesn't have a termination
  • The Elithion BMS has a termination that can be switched in and out
  • With the power off, use an ohmmeter to read the resistance across the 2 wires of the CAN Bus: it should be 60 Ohms
  • With the power on, use a voltmeter to read the voltages on the 2 wires of the CAN Bus. with respect to ground: about 2.5 V on each
  • With the power on, use a voltmeter to read the voltage between the 2 wires of the CAN Bus: CANH line must be more positive than the CANL
• After fixing any problems, cycle the Brusa off and on

We have discovered a bug in the Brusa software, which results is an "SDT Batt VoltHi: ERR" error.

Usually, this error is not seen, but can happen if the BMS is powered by a separate 12 V supply that can be on even if the Brusa is unplugged, in the following sequence of events:

1. Brusa unplugged; BMS powered and telling the Brusa that it can charge
2. Brusa plugged in

The error is avoided if the BMS is powered by the 12 V output of the Brusa:

1. Brusa is unplugged; BMS is unpowered because the Brusa is not plugged in
2. Brusa is plugged in, which then powers the BMS
3. By the time the BMS sends the Brusa a message to start charging, the Brusa is ready for it

If the BMS is powered by a separate 12 V supply that can be on even if the Brusa is unplugged, the error can be avoided in either one of these ways:

• Solution A:
  1. Brusa unplugged; BMS power turned off
  2. Brusa plugged in
  3. BMS power turned on
• Solution B:
  1. Brusa unplugged; BMS powered and telling the Brusa that it cannot charge (for example by forcing the HLIM: Home / Test / Force outputs / HLIM / Yes)
  2. Brusa plugged in
  3. BMS tells the Brusa that it can charge (for example by releasing the HLIM: Home / Test / Release outputs)