“Applies to the Inverter RS”, which already supports parallel
Parallel WITHOUT grid was already possible with the RS6000… (but never mentioned in the manual?)
I’m waiting for parallel wiring with grid, because I don’t need 3 phase or 3 RS units, and I don’t have the mounting space for a third RS6000.
“Is possible” and “Is officially supported” are two different things, just to add. It’s not considered a supported setup because there is no synchronization between two standalone-RS.
I would not encourage anyone to run two inverters in parallel, if they don’t talk to each other.
There is even a certain risk, when they have a dedicated ACOut, but shared neutral - if they fall in sync on their AC-signal and coincidently deliver their maximum power at one point, the shared neutral of any downstream branch could be hit with 2 times of its supported current.
I’m not asking you to share any trade secrets, but why does the RS/HS line not support parallel capability? Is it simply that all the magic that happens with VE.Bus and the firmware in the Multi/Quattro line hasn’t been ported to work via VE.Can? Thanks!
I think because its safer (and smarter) to start smaller when launching a new product, it limits liability. Especially with the more enthusiastic diyers (and those professionals who are closer to diy) who usually jump in with 2 feet before the professionals do.
Recalling of course that the larger models use and external relays to synchronise grid connection rather than all their internal ones like the older units.
Hasn’t the RS line been around for more than three years already? They’re not available at all in North America, so it’s a rather moot point here, but I was just curious why. Thanks.
Now all the supporters and die-hard fans of the red flag will start singing the same old tune: “Why do we need an external transfer switch when our beloved red brand already comes with the full all-inclusive package? No need to spend any extra money!” 
High voltage 5 minutes… So far all the HV stuff i existing installs is in a controlled testing environment.
The RS line isn’t the high-voltage line. The HS is the high-voltage line. But the RS line has been around for several years (I just don’t know how many) and yet also doesn’t support parallel installation. That’s what I’m asking about and why I suspect it’s more about the functionality not being ported over from VE.Bus systems.
I believe it’s the fact that with current HW/SW you can’t disconnect and/or connect all inverters’ relays in the same time (millisecond range).
Even with 2 devices, the 50A internal transfer relay will be at the limit (11.5kW), when the inverters are capable of up to 2x9kW for short period of times, so someone could have installations and loads with over 11.5kW.
And if one relay is slower the difference will be on the remaining one which can end up with welded contacts…
I was thinking along these lines and with some imbalance in parallel set ups this will be an issue.
And then different speeds of opening and closing even if you got wiring perfect (if that is even possible) then you have hardware tolerances/variances as well.
3 relays per unit, 6 on a phase of there are just 2 units in parallel, plus then the other 2 phases… Hmmm
Thanks @alexpescaru and @lxonline. That’s good information. The datasheet for the HS19 says “Future hardware revisions will support parallel operation.” The RS datasheet just says not possible. I dug a little deeper and also asked Claude. It seems that VE.Bus is a real-time, synchronized, deterministic bus. CAN-bus isn’t any of those. So, will future versions of the HS line add VE.Bus or a separate bus between units to maintain synchronization? Place your bets! haha. No, don’t gamble. It doesn’t end well in the long run. 
VE.Bus is a master/slave communication bus. The RS485 standard.
It’s easy for one from many to “draw the short stick” and become master and then all will listen.
But CAN bus is no less.
Has the same speeds, or bigger, have native hardware error corrections, automatic arbitration and some more…
Also the CAN ID values, that must be assigned for each node, play a big role in who “talks” and must be let to talk and who “listens”.
So, the same things can be done with CAN… Pardon the pun… 
If you ask anyone involved in today HW and SW industrial environment, CAN bus wins on 95% aspects versus RS485. The sole thing I am thinking where RS485 could win is distance. Over 1km distance between devices, but this is not the case here…
That because the RS485 is a master/slave communication and the master must talk sequentially with all slaves. By the time some slaves receive the data, the AC phase angle may be already shifted, resulting in a possible catastrophic phase mismatch.
On CAN, because CAN is a hardware-arbitrated broadcast bus, the master can broadcast a single synchronization frame. All slave inverters receive this frame at the exact same physical microsecond, so they can instantly lock their PLL simultaneously.
But the beauty is when an error appears, for example an inverter failure.
On RS485, the faulty inverter must wait until the master polls it to report the error. During those milliseconds of delay, the remaining healthy inverters will dump massive amounts of current into the failed unit, compounding the damage.
With CAN, the faulty inverter instantly broadcasts an emergency message on a high-priority ID, which will override all other network traffic. The other inverters read it instantly and isolate the faulty unit within microseconds.
Most products intend to support parallel use. Certification tends to be the biggest initial requirement for a new device, to drive adoption. When there is adoption parallelism is the next obstacle which in turn affects certification and may or may not need hardware changes to work reliably.
I seriously doubt victron haven’t considered this in R&D, but then, large scale systems haven’t exactly been their wheelhouse, scaling with small increments comes with challenges.
