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Topic starter
February 10, 2025 10:19 pm
I have an EG4 Wallmount battery working with a Victron Inverter/charger. I would like to know what determines the minimum battery state of charge (SOC cutoff) level, and how it is set. Does the battery BMS set this, or is it the inverter? If it's the BMS, is it changeable? Can I make it 10%? How is this done?
Also, the battery is capable of supplying 200A continuous output and has a 200A circuit breaker on the output. Does the BMS also have an electronic current limit? If for instance the output cables were shorted and the circuit breaker failed, would the BMS limit the output to 200A? Is the BMS current limit settable? Can I lower it to 100A?
Thanks
Dave
Topic starter
February 11, 2025 9:44 pm
What do you mean by through the inverter? I suppose if the battery is connected to an EG4 inverter, and has CAN bus communication, then the SOC cutoff is programmed at the inverter front panel, but is it then programming the battery BMS via the CAN bus, or is it programming the inverter to read the battery SOC and stop charging at the cutoff point? I want to know because I'm not using an EG4 inverter.
Is there a document available that describes in detail what the BMS actually does in the Wallmount battery and how to program it, if indeed it's programmable? I want to program the SOC cutoff and the discharge current limit if possible and I'd also like to know what its charge algorithm is, if it has one. My system has a mode available where the charger is controlled by the battery BMS and in that case I'd like to know what the battery charge algorithm is ie; Bulk V, Absorb V, Float V, currents, etc. Thanks.
February 13, 2025 7:29 pm
I’m not familiar with the wall mount batteries. All the settings you are talking about are programmed in my inverter. I believe most BMS’s look at voltage, so if the battery is taken to 50 volts and the charged to only 55 volts at some point the battery is 0% at 50 and 100% at 55. If it’s taken down to 46-47 volts and charged to 56 it will the recognize that 46 is 0 and 56 is 100. I think most new batteries are supposed to be cycled down to 47 or so and up to 56 around 7-8 times to establish good accuracy for SOC. I make sure mine are drawn down to 46-47 and the recharged to 56 a couple times a month
