+1 on that! 
instead of getting rid of the 3kva …Can one install a 3kva and a 5kva inverter together?
Not in parallel, no. Units have to be identical.
And what Plonkster means here is actually buy them at the same time, as in that identical… Not a year apart, as even different production runs have minor differences that causes “unknown gremlins”
G
Well, if you know what you are doing and you understand what might be needed to add a little bit of extra resistance (ie cable length) to the one side, I would not exactly call them “unknown”. But that’s why paralleling is a task best left to an experienced installer, because to the average sparkie this stuff is often dark voodoo, and the best way to avoid weird issues is to… well… avoid them from the start.
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Not that bad. On the 5kva MP 2 there use to be a hardware version before the 16th week of 2021. (If my memory serves me well) and a new version after that date. Before and After has a gremlin cage somewhere inside. All the production runs before that date works together well and all after that date does well. We often add units to instalations 2-3 years old without any issues.
3kva units does not have that issues and we have added a new one to a 3 year old unit without any issues whatsoever.
12 posts were split to a new topic: Inverters in Parallel: Impedance Discussion
I split this discussion off to here: Inverters in Parallel: Impedance Discussion - #11 by vlanone
My cousin in Pta, sold him 3 x 3kva’s for parallel setup. Reason, he wanted the redundancy.
Whilst still under warranty, think like ±3years in, Eskom woes blew one.
To keep paralleling, he had to to replace the other two. As per Victron, or find a older model to put back up. In that time, a newer firmware 3kva came out, no old stock around.
He now has 1 x 15kva beast.
In that same period, guy in Cpt wanted to add more 3kva in parallel to his 3kva. His firmware, older, nowhere to be found at the time. Put the two in contact, Pta sold him 3 x 3kva’s. Both problems solved.
So I think it is timing. If there are niggly issues, or Covid and part shortages, and stuff is upgrade/fixed quietly going forward, that at times it can have a ripple effect for backward compatibility.
There are 3 kva units pre 2019 if I’m correct on a different chip than post 2019. Those can not work together.
The 3 kva’s on the new chip number does not have the same issue as the 5 kva’s on the same chip number after the new hardware version has been released.
My answer above was based on same chip number versions. We have experienced 0 issues with adding 3 kva units using the same chips even with a 2-3 year difference in manufacturing date.
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