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catraz avatar image
catraz asked

SIMPBMS and Tesla batteries

Hi Folks. I'm looking for some support or guidance from the brains trust. I am using 8 Tesla Model S battery Modules with a SIMPBMS in a 48V system. The SIMPBMS is connected via CANBus to an EasySolar II (Multiplus II GX effectively). I'm using an ESS Assistant and DVCC. It all works well, other than the depth of discharge. The Multiplus reports Low Battery on L1 and starts drawing from the grid once the battery voltage falls to ~40.6V, or 33% SOC (6S battery). The firmware is all current and shouldn't have the old limitations. I can't see how to draw deeper in the battery. Please note, this isn't shouldn't be inverter start/stop issue with the known limitation of inverter restart voltage as the load on the inverter is constant.

Thanks

MultiPlus Quattro Inverter Chargerlow battery warning
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2 Answers
Meine_Energiewende avatar image
Meine_Energiewende answered ·

There is no possibilty to change this. It is firmware related in the Multiplus. 40.6 Volts is btw in a 12s System. The energy you would get below this point is marginal as the voltage drops rapidly -> see attached graph. In Terms of service life you should even not go deeper. The packs will last a lot longer if they are not discarged to deep and not charged over 49.2 Volts.

Jens


tesla-module-charge-curve-850x478.png (375.4 KiB)
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freds avatar image
freds answered ·

You need to set SimpBMS to report charge based on battery voltage level.


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 :1

3 - Current Multiplication :1

7 -Can Current Sensor : LEM CAB300/500 series

q - Go back to menu

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