I have a Victron system consisting of a Multiplus 2 48V 5000 and two Pylontech US5000-1C 4.8kWh batteries, ESS, Cerbo gx, and a Dynamic Energy Contract. This system is connected to phase L1, and it works fine.
Problem: My old Omnik 5 PV inverter is connected to two sets of eight 270Wp panels. The system is connected to phase L2. My mains voltage on a moderately sunny day is 238 volts, with a return current of approximately 6 amps. This works perfectly.
When the sun comes out, the mains voltage and the return current rise to 10 to 12 amps. The mains voltage also rises to 245 volts, but then the Omnik inverter switches off. The mains voltage drops again. The inverter waits 20 seconds, then restarts and switches off again at 245 volts. This repeats itself continuously throughout the day. Question:
I want to replace the old Omnik PV inverter with a Victron easySolar 2 GX 5000, which I can connect to the two solar panel arrays and the existing battery array. This allows me to both charge the batteries and feed power back into the grid on phase 2.
Question: Can I connect the easySolar to the existing Cerbo inverter on the Multieplus 2?
I see both have GX inverters. Is this possible?
If there are other options, please let me know. I might add one or two more Pylontech US5000-1C 4.8 kWh inverters to increase the storage capacity.
Does the voltage also rise when your Omnik is switched off? Or does it remain around the 240V mark? If it stays low without the Omnik, it could mean the wiring inside your house from the PV inverter to the fusebox is too small.
One way to find out is measure the voltage with a multimeter both at the terminals of the Omnik and on the terminals of the breaker. There should be a minimal difference (max. 1 to 2Vac)
Thanks for your response, I did an investigation of the cabling which is different than I thought.
From the main group box go two cables 5x4 squared and a 5x6 away from the connection box Omnik comes a 5x4 power cable.
Now it turns out that the Omnik cable does not come from the main group box but from a box that is fed with the cable 5x6 of which a three-phase group 5x4 runs to the connection point to which the Omnik is connected, last piece a phase is approximately 2 meters 2.5 squared
Mains voltage in the main meter cupboard (measured with a Flux meter) is now 233 volts on each phase
Measured on the Omnik connection, it is also 233 volts
The Omnik now supplies approximately 1.2 Amp when the supply returns increase, the mains voltage also rises on that phase
Also in the main meter cupboard, the mains voltage on summer days is higher on the three-phase approximately 238 to 243 volts
Up to 6 AMP feed-in it goes well, it goes wrong with more sun if the feed-in goes to 12 amp the mains voltage then rises to 245 volts then the Omnik switches off and the mains voltage drops again.
I have already connected the installation to a different phase but the same thing happens.
That means the wiring will not be the issue. Unfortunately.
Judging by your name, I would say you reside in the Netherlands. Our grid code allows the solar inverters to supply up to 253Vac grid voltage. I could mean your Omnik is set to the wrong grid code if it curtails at 245Vac. Maybe there is a setting for that, but it might need a installers code to be able to change that.
The actual voltage coming in from the grid is well within specification, so the grid operator will not do anything.
I found the manual, but it doesn’t answer my problem. Settings can’t be changed either. The manufacturer no longer exists.
My supplier from 10 years ago blames the problem on excessively high mains voltage. Given its age, he advises me to replace the inverter with a more modern PV inverter, which can handle the higher voltage better. I’m seeing these messages more often online. I think there’s no other option than to replace the Omnik. The question is: what’s the best solution?
I already have a Victron MultiPlus 2 system with Cerbo and two batteries.
I already have two sets of eight PV panels, each 270 Wp, and I’d like to reconnect them.
One solution is two MPTTs, but then I can’t feed back into the grid, or a MultiRS Solar48-6000.
The two sets of PV panels can be connected to this, and I can connect them.