I have read on the forums that it’s fine to mix batteries as long as they are the same chemistry. I am also assuming that I will keep the BYD’s BMS connected and “in charge” and not connect the data side of the new batteries. Is this correct? If so, would the system “just” work and simply charge/discharge at a slower rate, with the Victron components of the system being none the wiser of what is actually happening?
Also, I was also thinking about adding a contactor between the existing busbar and the new batteries, to be able to disconnect them based on a variety of safety-related criteria (though I presume the JK-BMS would disconnect the individual batteries if any of the current limits is breached). Is that overkill?
Yes, you can mix batteries of the same chemistry. No, you should not use closed-loop battery communication when using incompatible BMS’s. I would disconnect the BYD comms and use a Victron battery monitor to keep track of battery SoC, etc. You would also lose much of the DVCC functionality.
There’s nothing wrong with the approach so long as you use a Victron battery monitor and charging settings configured natively for each charging device.
With the serial battery, I would then see the DIY battery in Cerbo GX as it’s own device, alongside the existing BYD battery, is that correct? And I can then select the BYD as the “controlling” BMS to retain all the DVCC functions, right?
The BSC is also a very interesting project, it seems that it could be set up to monitor whether the BMS is alive and disconnect a contactor if it’s not, thus shutting off the entire new battery.
both solutions aggregate data from the batteries/BMSs and create a new virtual battery. In Venus OS you will see the aggregated virtual device, at least for the BSC.
The BSC can also merge data from Neey balancers, additional temperature sensors and create custom rules.
Interesting with BSC is the dynamic charge voltage feature keeping highest cell voltage in a save range by limiting CVL.
I am currently setting up such a system.
Yes, you cannot mix different cell chemistry and/or amount of cells. The solutions will merge data only.
I have just checked, the nominal voltage of the BYD battery is 51.2V, and it communicates via CAN a CVL of 58.4V and CCL 216A.
Both of the parameters seem quite in line with the standard 16 cell setup and also the defaults usually set in the JK BMS (in terms of CVL). Am I understanding it right?
I quite like the idea of the BSC - do you know if it is possible to purchase a kit to assemble one? I’ve checked the official page but they only seem to sell accessories, not the main boards
After the great links were shared, I did more reading, I concluded that I may be able to get away with not using the serial battery, as the JK BMS should be able to talk to the Cerbo directly via CAN.
So it’s “only” the matter of creating an aggregate battery in (ideally) software of the Cerbo, will keep digging
Hm, did not know that this feature was under development - would you be able to point me to more information re. Venus OS Virtual battery? I’ve tried googling but did not find anything but a few mentions in changelogs.
