So i currently have a 3 Phase setup with 3x Multipluss II Inverters. The system currently allows me to be completely off-grid. on the odd ocasion i will switch over to mains if the sun did not pop its head the entire day and i will end up using not more than 2kWh early morning.

My Main db board is configured for three phase, but my laundry and lounge is on one phase, meaning when Aircon is on the one inverter takes serious strain when the washing machine is churning.

I can re-wire the db board but i would prefer to leave it as is and instead link my 3 inverters in parallel and changing it to a single phase system. this will give me around 7.5kWh accross the three inverters and a bit more at peak.

Without spending a dime i am thinking of doing the following:

 

I will disconnect and terminate 2 of the incoming phases and take the remaining phase to my inverters in parallel. I will then remove the additional two live wires going to my main Db and bridge the single live wire to the other two terminals on my 3-Phase main breaker.

My question .... will this work? is one able to bridge on the main breaker like that?

Do i need to change any wiring on my Earth leakage if i do this, or can i leave it as is.

Side note... i am not feeding back, nor do i intend on feeding back.

 

@plonkster i believe i can just use the VE.Bus quick configure to re-configure the inverters from 3P to 1P parallel. Can i make a backup of the assistants and just reload them once the configuration is done, or does the 3 inverters in parallel require a different assistant configuration for charging batteries?

Edited March 6, 20197 yr by stoic

28 minutes ago, stoic said:

believe i can just use the VE.Bus quick configure to re-configure the inverters from 3P to 1P parallel. Can i make a backup of the assistants and just reload them once the configuration is done, or does the 3 inverters in parallel require a different assistant configuration for charging batteries?

I believe you did some things with relay assistants, if I recall, and if you did the best angle would be to look at the documentation. I cannot remember right now how that works exactly, the documentation usually tells you if the assistant should be on all the multis or just on the master.

2 minutes ago, plonkster said:

I believe you did some things with relay assistants, if I recall, and if you did the best angle would be to look at the documentation. I cannot remember right now how that works exactly, the documentation usually tells you if the assistant should be on all the multis or just on the master.

Not a biggy... i'm starting to find my way around the Victron firmware  . Will double check the manual

Wait... Wait... I am misreading the diagram? That doesn't look right.

What is your Grid feed? 3 Phase or Single Phase???

Back to the actual OP question:

If you reconnect your other two phases back to Mains, and then only use your system on a single phase (backup only, not grid feed!), then you will be ok. But that diagram (by joining the poles together), is wrong without any other context...

1. Please don't allow feedback to Grid on only one phase! - This will give you more headaches and possibly smoke than you need in a 3 phase setup!
2. You need a decent electrical guy to advise you on the feedback and phases, and a correct neutral point. Stuff can get easily out of whack when you isolate a phase without comoning the neutral and earths correctly. It seems simple, but if done slightly incorrectly you will have floating voltages as high as 110V AC at points. Your current setup negates most of that by either being isolated or common across phases.
3. Please don't wire this as your diagram suggests, rather replace your 3P breaker with the correct single breakers on each single phase, although it may be simple to you, any electrical bloke (especially government or inexperienced) could easily misunderstand the wiring. (Note: this is just discussing what you proposed above)
4. If you are prepared (which it seem you are from your responses), get a damn good Victron installer to work it all out (again you seem to like the Victron stuff which is awesome just pricey). I am a qualified electrician who dables in Solar quite deeply in my private capacity, but I still think that any 3 phase solution has to be evaluated properly. There is too much risk in making a mistake.
5. 3 Phase brings an entire set of challenges vs Single phase. Although we tend to treat it the same (each phase is a single phase, neh?). If you miss the common Neutral and Earth between these phases by bad isolation/commoning when trying to split up a phase you are risking your home possibly going up in flames if done wrong! (Yes, this is a horror story and not really likely, but I have seen far too many bad isolations go south enough to cause fiery ends). If there is a shorter route, no matter how improbable, Electrons/Electricity will find it!..

Now that I have put the fear of a flame ridden death into you... What you are suggesting is a great solution. Just get it double checked (especially if you think you are going to do it yourself). It is worth the call out to both a high end electrician and a qualified Solar installer to confirm your calculations. You are working with 3 Phase here, and even decent home DIY and qualified electricians make mistakes... It is worth it to double check that there can be absolutely no feedback or isolation that creates a dangerous voltage/current situation.
 

Mine is done like that, 3P to 1P but I had three separate EL units, one on each phase because I didn't have any 3P specific equipment. I now run a single Quattro on the converted 1P.

PS. The utility supplier probably did something on their side also, perhaps replace the 3P meter with a 1P meter, who knows.

1 hour ago, KLEVA said:

What is your Grid feed? 3 Phase or Single Phase???

3 Phase

1 hour ago, KLEVA said:

1. Please don't allow feedback to Grid on only one phase! - This will give you more headaches and possibly smoke than you need in a 3 phase setup!

I'm not feeding back, i don't intend on feeding back either

Quote

4. If you are prepared (which it seem you are from your responses), get a damn good Victron installer to work it all out (again you seem to like the Victron stuff which isawesome just pricey). I am a qualified electrician who dables in Solar quite deeply in my private capacity, but I still think that any 3 phase solution has to be evaluated properly. There is too much risk in making a mistake.

I am no sparky  and i knew nothing about solar, this forum guided me to my current three phase self install. Yes, wires needs some trunking, but the system is holding pretty well. 

 

1 hour ago, KLEVA said:

5. 3 Phase brings an entire set of challenges vs Single phase. Although we tend to treat it the same (each phase is a single phase, neh?). If you miss the common Neutral and Earth between these phases by bad isolation/commoning when trying to split up a phase you are risking your home possibly going up in flames if done wrong! (Yes, this is a horror story and not really likely, but I have seen far too many bad isolations go south enough to cause fiery ends). If there is a shorter route, no matter how improbable, Electrons/Electricity will find it!..

I'm trying to move away from 3 phase . the image on the left is current three phases coming to inverters, and then to DB. The picture on the right is how i think it should be changing it over to a single phase system.

Thanx for your feedback, there are definitely a few things i'll consider.

Oh, and those blue things are inverters... not appliances maybe i should have marked that clearly.

 

Edited March 6, 20197 yr by stoic

Just now, Ingo said:

Mine is done like that, 3P to 1P but I had three separate EL units, one on each phase because I didn't have any 3P specific equipment. I now run a single Quattro on the converted 1P.

PS. The utility supplier probably did something on their side also, perhaps replace the 3P meter with a 1P meter, who knows.

I have 3 phases coming from pole outside, each with there own meter, and ... no equipment running from my house DB is three phase. The rest of the plot i will leave on 3 phase but they all have their own db's

And the best part is that AC Out 1 feeds the old, but now combined, P1 and P2 and I have AC Out 2 feeding the old P3. My heavy loads are on the old P3 feed and drops out once the power goes out leaving the combined P1 & P2 to run from the inverter. Works a treat!!!

3 minutes ago, Ingo said:

And the best part is that AC Out 1 feeds the old, but now combined, P1 and P2 and I have AC Out 2 feeding the old P3. My heavy loads are on the old P3 feed and drops out once the power goes out leaving the combined P1 & P2 to run from the inverter. Works a treat!!!

Yeah ... that is the benefit of having a db wired in three phase  except, if you are like me, and lights is on one phase, ALL PLUGS on second (including aircon) and geysers and pumps on third, in this scenario i will always need a light and a plug

 

12 minutes ago, Ingo said:

And the best part is that AC Out 1 feeds the old, but now combined, P1 and P2 and I have AC Out 2 feeding the old P3. My heavy loads are on the old P3 feed and drops out once the power goes out leaving the combined P1 & P2 to run from the inverter. Works a treat!!!

Wait ... you actually gave me a great idea here ... geysers and pump can go on non-critical loads... and plugs and lights go on critical ... then again ... i never use mains, it is solar during the day and batteries at night, so non-critical loads will never have power  

But, in bypass you will charge batteries and Will feed loads with only one phase. Is It enough?

2 minutes ago, Javi Martínez said:

But, in bypass you will charge batteries and Will feed loads with only one phase. Is It enough?

The inverters are not set up to charge batteries on bypass, so it will only feed loads

Edited March 6, 20197 yr by stoic

7 hours ago, stoic said:

Wait ... you actually gave me a great idea here ... geysers and pump can go on non-critical loads... and plugs and lights go on critical ... then again ... i never use mains, it is solar during the day and batteries at night, so non-critical loads will never have power  

My own final design (not done yet $$$) will use a GTI on AC Out 1 which will feed power to both AC Out 1 and AC Out 2 during the day and use normal grid power at night. If grid power fails during the day I am sorted, if it fails at night P3 drops out and I run on batteries alone. Perhaps this could be a possible solution in your case.

So i finally did the switch from 3P to 1P on main building only. The image i drew out above was the right configuration. I had an electrician look over it and he also looked at my current setup.

@plonkster, just a note on VE.Bus configuration. If there is no ESS assistant set up for my pylons then the inverters displays "Battery Low" in order to set up an ESS assistant i need to enable feedback for South Africa (I cant have it set to None, it wont allow me to add an assistant). So i have to enable feedback then create the assistant, then disable feedback again. It seems a bit odd that i have to enable feedback to add an ESS assistant. Maybe its something that the devs can look at.

oh, and once again... thx for making my Solar Dream come true with all your help. I really appreciate it.

4 hours ago, stoic said:

, just a note on VE.Bus configuration. If there is no ESS assistant set up for my pylons then the inverters displays "Battery Low" in order to set up an ESS assistant i need to enable feedback for South Africa (I cant have it set to None, it wont allow me to add an assistant). So i have to enable feedback then create the assistant, then disable feedback again. It seems a bit odd that i have to enable feedback to add an ESS assistant. Maybe its something that the devs can look at.

ESS cannot work unless it can tie with the grid. The current implementation is correct. Disabling it in yours is wrong 🙂

If you want to run with the relay-assistant self-consumption thing I showed you, remove the ESS assistant completely and use only the flag+relay assistants+ignore AC config.