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Help my planning for a 3ph hybrid roadmap


Jakes Louw
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OK, I now have a money reserve to "play" with.

I want to start as 3 phase grid-tied and a small PV panel array (for obvious reasons), let's say 6 x panels for the minimum DC input voltage that appears to be around 192VDC on most 3ph solar inverters, and then expand the PV to a point where I can handle daytime peak load on PV (usage is around 50kWh between 08h00 and 16h00 but at this stage, an undetermined peak load, although simple maths indicates around 7kW ), but have the option of grid feed as I have a suspicion that my roof area is going to be too small for potentially 20 x 440W Canadians. Later on I want the option of mostly off-grid with grid in emergencies. So this I understand implies a hybrid..........but I'm struggling with my roadmap.

Any advice and guidance is appreciated (I am talking to Steve at the Powerforum shop but it's not fair that he does my architecture without consultation fees).

 

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32 minutes ago, Speedster said:

Do you have specific need for 3 phase?

Yes, our supply is from a 400VAC transformer. It is just easier and better to feed all 3 phases straight off the bat and let the inverter manage the balancing. I think running 3 x 1ph inverter feeds would require a lot of control anyway, which is built into the 3ph inverters anyway as far as I know. I also have 3 x 1ph old style meters that can apparently run backwards 😀 😉  

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16 hours ago, Speedster said:

Their 5G inverters are 3ph hybrid, yes. Downside is they work off of high voltage battery, so you need to fork out a pretty penny for that.

True. Anyway, I contacted Livestainable about the Sunsynk and they pointed me at the Solis..........

So the question is:

How much work is it to start with a cheaper Grid Tie and migrate/convert the infrastructure to a Hybrid further down the line?

 

 

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39 minutes ago, Jakes Louw said:

True. Anyway, I contacted Livestainable about the Sunsynk and they pointed me at the Solis..........

So the question is:

How much work is it to start with a cheaper Grid Tie and migrate/convert the infrastructure to a Hybrid further down the line?

 

 

The price differential between a grid-tie and hybrid isn't that big. Personally, I'd suggest you get the hybrid inverter now and wire it as a grid-tie. You can then pretty easily add batteries at a later stage. Switiching out the inverter later is much more effort (and I think more expensive) than starting with the right hardware. 

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Just now, Speedster said:

The price differential between a grid-tie and hybrid isn't that big. Personally, I'd suggest you get the hybrid inverter now and wire it as a grid-tie. You can then pretty easily add batteries at a later stage. Switiching out the inverter later is much more effort (and I think more expensive) than starting with the right hardware. 

I wish it was so. A Solis grid-tie is almost half the cost of the Hybrid. 

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Just now, Jakes Louw said:

I wish it was so. A Solis grid-tie is almost half the cost of the Hybrid. 

Ah, I forgot you're commited to the 3-phase situation. That really does drive the hybrid prices up quite a bit. Not only on the inverter, but on the battery side too. My home is currently wired 3ph, but I'll be switiching to a single phase when I roll out the solar install.

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I understand that you have a 380V connection at you farm but I don't think that obligates you to using all three phases. 

I am not 100% convinced that you even need a 3-phase solution, a single phase solution would be much cheaper. 

I have a 3-phase connection from Eskom at my house and it was converted it to single phase when I switched to solar. Easiest way to do it is to just have all the phases to the DB Board going to one phase on the supply from Eskom,  then you don't have to rewire everything on the DB Board

I have a 3-phase pressure pump that I run using a VSD which converts single phase to 3 phase for the pump so even if you have some 3-phase requirement can still be done.  

 

 

 

 

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3 hours ago, Sc00bs said:

I understand that you have a 380V connection at you farm but I don't think that obligates you to using all three phases. 

I am not 100% convinced that you even need a 3-phase solution, a single phase solution would be much cheaper. 

I have a 3-phase connection from Eskom at my house and it was converted it to single phase when I switched to solar. Easiest way to do it is to just have all the phases to the DB Board going to one phase on the supply from Eskom,  then you don't have to rewire everything on the DB Board

I have a 3-phase pressure pump that I run using a VSD which converts single phase to 3 phase for the pump so even if you have some 3-phase requirement can still be done.  

 

 

 

 

I'll have to see if I can run all the load on a single phase. As far as I know that is 100A or 23kW?

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2 minutes ago, Jakes Louw said:

I'll have to see if I can run all the load on a single phase. As far as I know that is 100A or 23kW?

Do you have any equipment that actually runs on 3 phase? Have you measured your load to determine the actual current draw of your single phase appliances. 

3 phase for a purely domestic installation is normally not required and simply there because the house was initially setup as 3 phase. 

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1 hour ago, Achmat said:

Do you have any equipment that actually runs on 3 phase? Have you measured your load to determine the actual current draw of your single phase appliances. 

3 phase for a purely domestic installation is normally not required and simply there because the house was initially setup as 3 phase. 

Yes, I have a borehole on 3ph. I live on a small-holding, I have cold-rooms and various other items that use over 100kWh per day. 

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3 hours ago, Jakes Louw said:

Yes, I have a borehole on 3ph. I live on a small-holding, I have cold-rooms and various other items that use over 100kWh per day. 

Borehole can easily be converted to single phase, speak to Neels at https://cfptechnologies.co.za/ and he will advise as to what you can use, he has gear to run up to 4kw 3 phase motors on a single phase 220V supply.

Not sure about the other stuff but he should be able to advise, worth investigating as it could be a better/cheaper option. 

I would stick an Efergy Engage on it for a month so you can see what your peak power requirements are, is relatively cheap and very handy to have in any case. 

Preferably get the internet attached cloud one so you can get all the data (if you have wifi available on the farm)

 

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On 2021/04/09 at 6:52 PM, Sc00bs said:

Borehole can easily be converted to single phase, speak to Neels at https://cfptechnologies.co.za/ and he will advise as to what you can use, he has gear to run up to 4kw 3 phase motors on a single phase 220V supply.

Not sure about the other stuff but he should be able to advise, worth investigating as it could be a better/cheaper option. 

I would stick an Efergy Engage on it for a month so you can see what your peak power requirements are, is relatively cheap and very handy to have in any case. 

Preferably get the internet attached cloud one so you can get all the data (if you have wifi available on the farm)

 

Shopping for the Efergy 3 phase kit right now.........thanks

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I see Hoymiles also have a 3 phase 1800/2250, recently launched - not available in SA yet? I have installed APSystems 1.1kw 3 phase balancing Micro inverters - but sadly no agents in SA anymore/currently. I do like the move towards 3 phase Micro inverters, much simpler - pro's and cons vs. the considerably more versatile hybrid String inverters. Also wondering whether it will not be cheaper in long run - replacing smaller Inverters as they fail vs changing a big inverter?

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