There is a different between what the HW theoretically can and what is officially supported.
As long as it’s not in the manual/datasheet (or announced in a news) I consider it as unsupported.
A beta test is a test if the HW and software really can do it and if it is reliable over a longer time before it gets officially released for everyone.
Yes, the Multi RS Hardware always was able to work without a battery, but the official release of that feature was just a few months ago. Before that it was in beta test and not officially supported.
So without committing to any official firmware release date (even beta release…) to support parallel operation, can you at least say whether the current Multi RS hardware is theoretically capable of supporting this or whether new hardware will be needed?
Thanks Matthias. Any chance of asking the development team? (private answer if public is unacceptable).
I’m going to have 2 Multi RS installed on my boat early next year; if they can be paralleled that’s great, if not we will have to change the boat wiring to separate out the cooker from the ring main, which is a PITA because this means splitting the consumer unit into two and dragging another feed cable through, which is not going to be easy…
WIth two Multi RS with AC inputs and battery connections in parallel but AC outputs separate, I assume they have to be defined as a pair (master/slave?) in system setup, since you can only have one inverter/charger controlled by a Cerbo and accessible via VRM? Otherwise things like input current limiting don’t work properly…
In this case, are the relays separately controlled for each unit?
The reason for asking is with the Quattro I use one relay for generator start/stop and another for external fan control (cooling fans for electrical cabinet which come on when the internal fans do) – is this still possible with two Multi RS?
I also have an immersion heater connected to ACOUT2 which is turned on and off by an assistant to act as a solar dump when the batteries are full, I guess I’d have to find another way to do this with the Multi RS since there’s no controllable ACOUT2 relay inside?
I have a Cerbo GX, so I assume this can do generator switching and use the Multi RS relay(s) for fan control.
This is why last week I had another software/hardware feature on my desired testing list when I find time. In above discussions I read a similar feature request. Using two MRS with AC-out coupled… than only one MRS connected to grid and somehow make it work despite the official narrative… Use firmware 1.26 and VC beta. Configure each MRS as “single phase” and set it L1 for example. Following error too many units with explanation will be showed and AC-in relay stays open.
Very clear error. But now switch off the “slave MRS” and within 30 seconds the “master” MRS will connect to the grid and start charging your battery bank.
This is a great solution for offgrid installations where 95% of the time the installation relies on solarenergy and the battery. Only in the rare occasion of generator or grid being needed you can than supply the customer with 50A transfer and also charge your battery.
This solution also works with threephase system… Thus allowing 6MRS or 9 or 12 etc… for the normal offgrid operation. While only using 3 MRS and the grid to power the load and charge battery when really needed. Not ideal situation, but enough for some.
Can we automate above scenarios? Yes you do not have to physically switch off the “slaves”. With the 1.26 firmware it’s enough to “open” the wire loop H/L switch (pin 5/6 on the black/orange connector) in combination with pin 7/8 on the same connector you can than switch off MRS’s that you do not want to be on at a certain battery SOC.
Just setting to switch the “slave” inverter off by a certain battery percentage in the VC menu does not work as that generates a switch off command to all MRS with the same “system instance” That’s why I came up with above solution.
Now if you don’t like the alarm #74 all the time, than also automate when you connect grid voltage to the MRS a simple relay and or Nodered using K2 on CerboGX for example can arrange that for you.
You see while not having a very simple MRS parallel firmware yet creative solutions can be made to tailor to certain applications. Wish you all the fun with your creativity.
No the Cerbo GX can handle many Stand alone MRS even when they are on the same battery. You can set “system instance” to separate which MRS and inverter RS are working together as a group.
For example I have an office system where 3 MRS are running only all the airconditioning and those MRS switch off when the battery is below 40%
The other 3 MRS are running everything else on the compound. Both systems are accessible through a single CerboGx. Look in the “system” configuration page of MRS and you find many more options than you used to have with VE-bus inverters.
