SimpBMS Setup for Tesla battery modules in parallel

Hi Everyone

Bringing my SimpBMS configuration on line and having a couple of problems.

My target environment is a bus conversion motor home with:

1. Victron Color control head
2. Victron Solar charge controllers
3. Singineer Inverter/Charger 6KW Tesla model APC6024DT
4. Two Tesla Model S modules connected in parallel.
5. SimpBMS for Tesla

My SimpBMSconfiguration:

1. SimpBMS 2.3 board
2. NEXTION display
3.LEM CURRENT Sensor CAB300-C/SP2 (Read documentation, VCC is connected to 12V for this sensor).
4.OMRON CONTACTORG9EA-3-CA-M2 (not using at the moment.)

All the above SimpBMS items were purchased directly from secondlife-evbatteries

My current status:

1.NEXTION display works well
2. Connected a terminal emulator to Teensy 3.2 compute module and see output
3. It is reporting that voltage as 45.6 as if the modules are in series.

Modules: 2 Cells: 12 Strings: 1 Voltage: 45.615V Avg Cell Voltage: 3.801V Low Cell Voltage: 3.799V High Cell Voltage: 3.803V D
elta Voltage: 4mV Avg Temp: 18.754C



Module #1 22.81V Cell0: 3.80V Cell1: 3.80V Cell2: 3.80V Cell3: 3.80V Cell4: 3.80V Cell5: 3.80V Neg Term Temp: 18.86C

Pos Term Temp: 18.52C

Module #2 22.81V Cell6: 3.80V Cell7: 3.80V Cell8: 3.80V Cell9: 3.80V Cell10: 3.80V Cell11: 3.80V Neg Term Temp: 19.03C

Pos Term Temp: 18.61C
CANbus 0.00mA 67% SOC 67000.00mAh



4. I entered the setup menu and then debug and set the ESS mode to 1
5. I went back to the setup menu and selected "c" for current sensor calibration
6. I configured the sensor type and for LEM CAB series

Current Sensor Calibration Menu
c - To calibrate sensor offset

s - Current Sensor Type : Canbus Current Sensor

1 - invert current :0

2 - Pure Voltage based SOC :0

3 - Current Multiplication :1

7 -Can Current Sensor : LEM CAB series

q - Go back to menu

Calibrating Current Offset ::::: ....................5 current offset 1 calibrated
Calibrating Current Offset ::::: ....................5 current offset 2 calibrated



7. I then went to the Battery Settings Menu with the "b" letter command

Battery Settings Menu
r - Reset AH counter

f - Reset to Coded Settings

q - Go back to menu





1 - Cell Over Voltage Setpoint: 4200mV

2 - Cell Under Voltage Setpoint: 3000mV

3 - Over Temperature Setpoint: 65.00C

4 - Under Temperature Setpoint: -10.00C

5 - Cell Balance Voltage Setpoint: 3900mV

6 - Balance Voltage Hystersis: 40mV

7 - Ah Battery Capacity: 100Ah

8 - Pack Max Discharge: 30.00A

9 - Cell Discharge Voltage Limit Setpoint: 3200mV

0 - Slave strings in parallel: 1

a - Cells in Series per String: 12

b - setpoint 1: 3100mV

c - SOC setpoint 1:10%

d - setpoint 2: 4100mV

e - SOC setpoint 2: 90%

g - Storage Setpoint: 3800mV

h - Discharge Current Taper Offset: 300mV
j - Discharge Current Temperature Derate : 40.00C



I then attempted to use the command characters "0" or "a" to try and alter the values to setup for modules in paralleland got no response to the requests.

So at this point I have the following:

1. Reported pack voltage is incorrect
2. Charge or Discharge current is not being shown on the NEXTION display.

Thanks

Fred

Hello Fred,

when changing values, confirm with Q, Q to get back to main screen, this way it is written to memory
You can alter more than 1 value in same sub menu, but do need to confirm with Q,Q>>main screen,
perhaps try it.

1 caveat about the Omron contactor not suited for low voltage high current storage battery, you will weld the contacts
best Carel

Hi Carel

OK, I write terminal emulators for a living and did a download of Termite and used it. I see that this emulator uses a separate command line input box and sends that output as a string of characters, not individually as you type them on the keyboard.

So a bad case of RTFM and unnecessary hubris on my part, thanks for the assistance in this problem.

My understanding is that relays can handle high amperage at lower voltage. The Omeron contactor is rated at 60 amps at 400V and 100 amps at 120V. Here's a little blurb on the subject that I found online:

---------------------------------------------------------------------------------------------------------
Relay Ratings and Limits

This does not necessarily tell you what the limits of the relay are. For instance, a 5 Amp relay rated at 125VAC can also switch 2.5 Amps at 250VAC. Similarly, a 5 Amp relay rated at 24VDC can switch 2.5 Amps at 48VDC, or even 10 Amps at 12VDC.

Choosing a Proper Relay Amperage
---------------------------------------------------------------------------------------------------------
I would think it is the amount of energy being switch on and off. In my case I am ganging all three sections of the relay in parallel and on/off events are going to be rare in ESS mode, just when the battery needs to be protected.

Any thoughts on how to diagnose the LEM current sensor problem?

Again thanks for your assistance.

Fred
PS. With both emulators there seems to be problem in that you can only attach serially one time for each power cycle (at least under windows 10).

Fred,
I don't know if aware of github.com/tomdebree,
check for SIMPbms manual, and latest firmware.



best regards
Carel

CarelHassink said:

Fred,
I don't know if aware of github.com/tomdebree,
check for SIMPbms manual, and latest firmware.

best regards
Carel

Click to expand...

OK, I had a bit of a learning curve to bring this up especially the confusion of wiring up the LEM CURRENT Sensor CAB300-C/SP2, as there is a tendency to follow diagrams verses reading detail in the manual.

The diagram shows connecting the current sensor to J2, where as this sensor requires running wires to connectors J4 and J5.

My final step will be connecting the contactor and then I will have full functionality.

Fred,

J2 is for analogue shunt connection
J4/J5 for a can-bus shunt like LEM CAB300/500
as per manual,

Glad to hear I could be of help,
best of succes with your build.


regards, Carel Hassink

Tesla model S modules are 6s and you have 2 of them in parallel so in your battery menu you want

Option "0" = 2 (because you have 2 batteries in parallel)
Option "a" = 6 (Because you have a 6s 24V system)