Hi I am creating an off grid equipment testing unit, I have worked out for the capacity need and the BYD 15.4kwH unit is the correct size.
My main question is around VE communication methods - as I’m an not having an inverter with any AC in the system, I am unsure whether I need a Cerbo GX to interface between the MPPT (Smartsolar 150/35) and the BYD BMS, therefore controlling the charge output from the MPPT charging the lithium battery or is the standard settings from the MPPT enough?
Would really appreciate any examples of similar systems?
Thanks.
You will need a GX, there is no other way for the BMS to manage chargers via CAN as DVCC is driven by the GX. Else you need to use a shunt for old school metering. Well, you can get away without a shunt but it is the best way for accuracy and be used with smart networking.
Given the cost relative to the battery, I’d go for a Cerbo.
The byd will switch off without a connection to the GX. So you need a way to keep it alive.
Hi is this from personal experience? Or am I able to find it in a datasheet somewhere? Cheers
Yes personal experience.
Also the victron online guide mentions it too.
See 1.2
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You are building a pure DC system right?
So the MPPT can be set to generate a certain voltage and forget about it.
This because the BMS, using that voltage should control its battery by its own.
That 150/35 by no means will have the ability to “harm” the 15kW BYD battery, even at its maximum current once you proper set the output voltage.
So the question is how to keep alive the BMS and the battery.
And that is by sending a certain frame with a certain ID over the CAN bus with a simple device capable of communicating over CAN bus.
Are you able to do this?
If not, a Cerbo-like device is the way to go…