BipedalPrimate
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Ghosty - what did your 'chap' (the mate of a mate
) advise?
Grid Tie Victron ESS with DIY LiFePO4 Battery in Australia - Regulatory Issues?
- Thread starter BipedalPrimate
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) advise?
BipedalPrimate
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Grakat,
Something like this?
There is some doubt whether a Grid Protection Relay would be required - but I think it would be.
Fronius Smart Meter tells Fronius Inverter to up/down regulate PV production to maximise 5kw grid feed in limit, .
Fronius inverter reports PV production to Cerbo.
Victron Energy Meter detects current flow from/to grid and (if Cerbo ESS is set up correctly) tells Multiplus to invert from battery when loads exceed PV production or charge battery if PV production exceeds loads.
Otherwise, excess PV above Multiplus invert/charge demand is fed back to grid.
Disadvantage is there will be no PV production with PV inverter on AC In when grid fails so it depends on how reliable your grid is.
Advantage is you are not constrained by the Victron 1:1 rule when PV is on AC In.
Yes this is similar to what I am thinking, except for figuring out the grid protection relay. There may also be an ~40m cable run between the Fronius and the Victron gear as the house will most probably get the grid connected stuff while the 14m x 14m shed and awning gets the offgrid gear.
New guy here (please be gentle).
I was under the impression a Multiplus II certainly "can" export (ESS mode 2 and 3) and thus very much interact with the grid.
Making it a "multiple mode inverter" under AS/NZS 4777.2:2020
Meeting CEC's "Multiple Mode Inverter - Battery Only" requires "AS/NZS 4777.2:2020" instead of "AS/NZS 4777.2:2020 APPENDIX M" (which, as you mentioned, it already has via SAA181339).
Not just that, but AS/NZS 4777.2:2020 also explicitly states:
To my ignorant eyes, both that CEC response and the entire CEC registration are off the mark.
Given those (publicly stated) requirements Multiplus II would qualify for CEC registration as "Multiple Mode Inverter - Battery Only".
Does it not have the right "flavour" of "AS/NZS 4777.2:2020" required for CEC's "Multiple Mode Inverter - Battery Only"? Or a finer point of such certification?
It seems unlikely that the wrong "type" was applied for with CEC (but I've seen stranger things).
BipedalPrimate
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I agree although there has been no advice from Victron nor CEC as to what is preventing registration.
Another trick for us all is this snapshot from the Rev 05 09/2022 version of the Multiplus-II 230v manual:
This little disclaimer is just below the table of symbols used on the enclosure - usually something I skip over.
So, remember to read 'generator' whenever you see 'grid', but the manual refers to 'mains' multiple times and even suggests you can feed back to the 'mains'. Try that with a generator and see how you go.
I think the main issue is not that the inverter itself is compliant but rather that Victron have not made any application to the CEC for approval for this inverter to interact with the grid. In my opinion the CEC is a body that really should be given a new mandate as they seem to offer opinions in some areas that conflict with established standards. Their interpretation of ELV vs the standard is a case in point.
KangaRooted
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I think you are spot on, and to this point, it will be a tall order to get any qualified electrician to sign off on the inverter knowing this (if it is not approved). Difficult - but I guess not impossible - again open to interpretation if you add 3rd party devices. The sparky doesn't want to be left stuck holding the ball. The Victron Multiplus II supports islanding mode when configured properly. The grid protection relay is advisable for a misconfigured system. Guaranteed someone would go to jail if they got the back feed bit wrong and electrocuted someone further up the line. It's probably the bit that matters the most.
I have given thought about the back feeding, and I do think that there is a bit of hype in regard to back feeding. For example, i have a 230V connection which comes direct from my Pole Transformer, and then the primary side of the PT is connected to an 11KV supply. I'm happy to be corrected if I am wrong in this regard, but I'm not thinking a Multiplus running at 230V would make very much 11000K on the primary side if it back fed the grid in an outage situation. The Multiplus would probably have its own significant emotional event and trip on over current as in essence I tried to power the grid from my Multiplus.
As the Multiplus is not allowed to see the grid here in Australia I will most likely put a changeover relay on the grid side of the Multiplus. That will then be compliant with our codes.
davidpb153
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I'm very interested in this setup. I was wondering if you ever progressed? Australian regulations seem seriously ott. Not allowed to install a light or a power point?
I was also wondering about a different way around the regulations.
Looking at my energy use, every day, there is a regular draw by the fridge and an external freezer (like 0.1 kW, but it is always on so over a day, it adds up and is the biggest user of electricity when the sun is down over a year). I try, but fail to always use my dishwasher/washing machine when the sun is up. The AC is fine in summer (it's on when the sun is on), but draws a lot in winter in the evening. So basically, if I could get a battery to power my fridge, it would cut most my usage. If it could power fridge, washing machine, dishwasher and split system, it could cut almost all use.
Would a sparky be willing to add a dedicated circuit (frankly I could wire it myself if it weren't for the regulations) to a 3 or 4 appliances from a diy battery (through a separate switch box). The battery would be charged through AC from the main house circuit as described by OP. I could easily program a raspberry pi to choose when to charge it taking into a account solar production and weather? It seems low risk for a sparky.
Basically can I have a home that has both on and off grid electricity?
I was also wondering about a different way around the regulations.
Looking at my energy use, every day, there is a regular draw by the fridge and an external freezer (like 0.1 kW, but it is always on so over a day, it adds up and is the biggest user of electricity when the sun is down over a year). I try, but fail to always use my dishwasher/washing machine when the sun is up. The AC is fine in summer (it's on when the sun is on), but draws a lot in winter in the evening. So basically, if I could get a battery to power my fridge, it would cut most my usage. If it could power fridge, washing machine, dishwasher and split system, it could cut almost all use.
Would a sparky be willing to add a dedicated circuit (frankly I could wire it myself if it weren't for the regulations) to a 3 or 4 appliances from a diy battery (through a separate switch box). The battery would be charged through AC from the main house circuit as described by OP. I could easily program a raspberry pi to choose when to charge it taking into a account solar production and weather? It seems low risk for a sparky.
Basically can I have a home that has both on and off grid electricity?
BipedalPrimate
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Multiplus II has two internal relays that disconnect the grid circuit in the event of grid falling out specs for the Grid Code selected so probably not a problem.
BipedalPrimate
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From what I can tell from regulations, that would work BUT:
- you will have to find a sparky that will do it - they tell me they are very busy in my neck of the woods.
- it may easier to get approval if you separate the charging device from the inverter as that way there can be no 240v connected to the grid even in the event of any device failure. You may want to consider a bypass switch that will power your loads from grid whilst isolating the inverter - just in case you need to work on inverter or batteries.
Approached 3 electricians so far. First two umm'ed and argggh'ed but declined after thinking about it for weeks - as mentioned they said they had too much work.
3rd electrician now having a serious look at it based on his questions. But it has only been 1 week
davidpb153
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Just wondering. Take this idea to the extreme:
Add a new switch box. Have 1 circuit that is tied Solar - Grid with feedback as per a normal house setup with existing solar (what I currently have). Except that switch box only has 1 output - one plug (plus perhaps one connection to an automatic transfer switch if possible). From that plug, you can charge the multiplus.
The multiples now feeds the old switch box, which feeds the house.
(Perhaps separate charging device and inverter as you suggest)
The sparky has to do almost no wiring. It's a quick job, single day at most (install one switch box and one plug, re-route solar and grid feed through the new switch box). Maybe a sparky can find time for a shorter job. Ideally, they would be to add an automatic transfer switch, so it can choose to power home from the grid if there is a problem with the inverter.
Add a new switch box. Have 1 circuit that is tied Solar - Grid with feedback as per a normal house setup with existing solar (what I currently have). Except that switch box only has 1 output - one plug (plus perhaps one connection to an automatic transfer switch if possible). From that plug, you can charge the multiplus.
The multiples now feeds the old switch box, which feeds the house.
(Perhaps separate charging device and inverter as you suggest)
The sparky has to do almost no wiring. It's a quick job, single day at most (install one switch box and one plug, re-route solar and grid feed through the new switch box). Maybe a sparky can find time for a shorter job. Ideally, they would be to add an automatic transfer switch, so it can choose to power home from the grid if there is a problem with the inverter.
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KangaRooted
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Still the same issue .... is it within 'the (stupid) regulations' and even if its a 50/50, can you find someone to sign off on it and ratify it with the electrical wholesaler in your area. Getting a multiplus to work on the grid is not hard; it's all those regs.
Look at the options for the sparky:
Sparky does the job and can't get the ESS system certified - Sparky in danger of you not paying them - massive headaches.
Sparky does the job and doesn't get the ESS system get it certified - his ass is in a sling by you (even if you say it wont be) and the electricity wholesaler - massive headaches.
Sparky doesn't do the job and says they are busy or its too hard or it wont meet regs - Sparky goes onto the next paying job - Sparky not in trouble with the wholesaler, you might hate on him, but he still avoids his ass in a sling - not a massive headache.
I know I'm missing the obvious other (nice to have) option:
Sparky does the job, sparky gets it certified and all goes well. But he's thinking about the top 2 scenarios REAL hard and doesn't even get this far because he knows what's ahead of him - especially if they gotta sign off on something they didn't do themselves - i.e. building your own battery, etc, etc.
I don't mean to sound negative about it - I want to see this succeed as much as everyone else here, but we're certainly up against it.
Regs are the reason so many electricians baulk at the task - even though it's not overly hard on the grand scheme of things.
Maybe do this: Install the solution, get a big fence, 2 even bigger dogs, lock the gate and put a "beware of the dogs" sign up. It could take years for someone to come and check on you lol
BipedalPrimate
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I have managed to at least get a quote for the installation that includes inspector approving.
However, after me having agreed to go ahead with the quote, sparky has gone quiet for a few days.
KangaRooted
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Fingers crossed for you that you can (legally) get it across the line!
KangaRooted
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@BipedalPrimate, any update on your sparky? Has he come back to you yet?
On a separate note I spoke with a designer here in Australia and was advised that setting up a Victron ESS system with a Multiplus was achievable here in Australia. They advised having the grid tie inverter at the end of the chain and then the Multiplus with a grid connection. The objective was not to export anything whatsoever, which is fine with me.
The grid tie inverter needs to be able to derate using frequency shifting so that it can dump load. Fronius, SMA and Fimer inverters are capable of doing it. There is also the 1:1 rule which means if you have a 5KW offgrid inverter then you can only have a 5KW max output grid connected inverter. I think this is so the Multiplus is able to shut down the grid inverter completely.
To kick all of this off I will put a 5KW grid tied inverter onto the house and put an offgrid system into my shed. Then once the shed system is running and reliable I will join the two systems together with a cable run. House is still being built so i am in limbo at the moment. My shed system is a baby 12V system running a DC water pump and a fridge only.
The grid tie inverter needs to be able to derate using frequency shifting so that it can dump load. Fronius, SMA and Fimer inverters are capable of doing it. There is also the 1:1 rule which means if you have a 5KW offgrid inverter then you can only have a 5KW max output grid connected inverter. I think this is so the Multiplus is able to shut down the grid inverter completely.
To kick all of this off I will put a 5KW grid tied inverter onto the house and put an offgrid system into my shed. Then once the shed system is running and reliable I will join the two systems together with a cable run. House is still being built so i am in limbo at the moment. My shed system is a baby 12V system running a DC water pump and a fridge only.
BipedalPrimate
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@KangaRooted Installation is scheduled for 26 June.
KangaRooted
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Unless the plan is to completely turn off the grid connection altogether, I don't understand why you couldn't/shouldn't/wouldn't have the inverter on the incoming line of the Multiplus. Afterall, the rule is that the Multiplus can't backfeed into the grid - not the grid tied inverter. The inverter charges your battery then continues to feed into the grid after the battery is full - (Disclaimer - I've NFI why you'd actually want to do this as the retail provider is stealing that feed in from you at 5c a Kw - but for the sake of the discussion... lets just pretend it might be a good idea
) This would mean you don't need to consider the size of the grid tied inverter as much too.Was there any feedback from the designer on why one option might be okay and not the other? I'm keen to understand the thinking behind it.
Also, what did the designer say about "build your own battery"?
BipedalPrimate
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I assume you will have the Grid Tie Inverter on the AC Out of the Multiplus.
With Victron ESS & Fronius you do not need to use frequency shifting - see the Fronius Zero Feed-in option in ESS. It uses a direct communication connection between the Cerbo/Venus & Fronius for the Cerbo/Venus to control Fronius PV generation.
The 1:1 rule only applies when the PV inverter is connected to Multiplus AC Out. This is so the max output of the PV inverter does not overwhelm to max output of the Multiplus.
AS @KangaRooted mentioned, there is no limit on the PV inverter size when it is connected to the Multiplus AC In. In this case you do not need to worry about frequency shifting/limiting PV inverter output.
What communication standard would the PV and Multiplus be using to control the PV inverter? if it can't control on the AC out by frequency shifting then that will be a challenge to me as the PV and Multiplus will be ~40m apart in my desired installation.
I would like to have the capability to utilize the Fronius in a grid outage or isolated arrangement. If I end up going to Amber as my provider there are times I wont want to use the grid at all, and other times where I will utilize the grid connection.Unless the plan is to completely turn off the grid connection altogether, I don't understand why you couldn't/shouldn't/wouldn't have the inverter on the incoming line of the Multiplus. Afterall, the rule is that the Multiplus can't backfeed into the grid - not the grid tied inverter. The inverter charges your battery then continues to feed into the grid after the battery is full - (Disclaimer - I've NFI why you'd actually want to do this as the retail provider is stealing that feed in from you at 5c a Kw - but for the sake of the discussion... lets just pretend it might be a good idea
Was there any feedback from the designer on why one option might be okay and not the other? I'm keen to understand the thinking behind it.
Also, what did the designer say about "build your own battery"?
BipedalPrimate
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It uses Modbus via TCP over ethernet from Cerbo
See 4.3.13. AC-Coupled PV - Zero and Limited Feed-in with Fronius AC PV
So I will have to provide a direct connection between the Fronius and the Cerbo. Might have to pull some Cat6 when I do the cable runs to my shed.
KangaRooted
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Do yourself a favor and pull 2 or 3 runs. You never know when those extra ones may come in handy and you dont wanna have to dig up again if you drop it in a trench....
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