Solar PV design advice

[cbk]

Hi, I'm looking for design guidance and recommendations for best Inverter & storage options for a DIY install as part of a new house build.  Im not looking for an MCS FIT approved system but just to get maximum benefit from solar PV at lowest cost and would like the capabilitty to run off battery power during the evening and ideally during a power cut.   I have a qulaified electrician ready to connect up the system, but I'm a  bit confused by all the options. So far I have purchased 24 x Canadian Solar 370W panels (Model: CS3L-370MS-MC4-F30), which is the maximum I can fit on the south facing roof arranged as a 3x8 array.  Roof is being tileds now so need to finalise the design asap to allow panels to be installed.  Mains supply is single phase and I have checked with my local network provider that they are OK with me connecting a 9Kw array to the grid. Budget is tight so need the option to add additional batteries at a later stage.  Any suggestions on best combo of Hybrid Inverter and storage would be really helpful.

[Dillsue]

If you dont know the system design/inverter model, are you sure you have approval to connect a 9kw system to the grid? Even for informal "approval" I had to email and discuss the system I had in mind to get informal agreement before I put in the formal G99 application.

 

If youve already agreed some aspects of the design such as export limitation you probably want to post the details

[Nickfromwales]

13 minutes ago, Dillsue said:

If you dont know the system design/inverter model, are you sure you have approval to connect a 9kw system to the grid? Even for informal "approval" I had to email and discuss the system I had in mind to get informal agreement before I put in the formal G99 application.

 

If youve already agreed some aspects of the design such as export limitation you probably want to post the details

Just spoken to a DNO to arrange 3ph for a client. No need for specific info at that stage, other than expected loads / combined max microgeneration output etc, and were awaiting a decision currently.

[Dillsue]

1 hour ago, Nickfromwales said:

Just spoken to a DNO to arrange 3ph for a client. No need for specific info at that stage, other than expected loads / combined max microgeneration output etc, and were awaiting a decision currently.

No doubt thats the case for you but the OP is somewhat different in that hes still looking for concept design.

 

If DNO is only considering a 9kw array and no batteries then DNO may have given informal approval without considering a potential doubling of export with AC coupled batteries?? Maybe the OP has agreed an export limitation system or exporting via one or more G98 inverters?? Be good to know the basis of the "approval" for a 9kw connection.

 

[SteamyTea]

4 hours ago, cbk said:

Roof is being tileds now

Shane, you could have gone for a roof integrated system and saved on tiling.

[joth]

1 hour ago, SteamyTea said:

Shane, you could have gone for a roof integrated system and saved on tiling.

not to mention you would also save on anti-pigeon netting and long term maintenance costs, and get better aesthetics and improved resale value....

 

[cbk]

For info panels are in roof intgegrated type and the informal approval was for PV only and suject to a G99 approval once system design was complete.  Ive only recently considered the option to add batteries so can see this will create more issues.  Hence the post on here for some recommendations.

[joth]

13 minutes ago, cbk said:

For info panels are in roof intgegrated type and the informal approval was for PV only and suject to a G99 approval once system design was complete.  Ive only recently considered the option to add batteries so can see this will create more issues.  Hence the post on here for some recommendations.

Nice.

 

In terms of invert/battery recs:

- I have solaredge (HD-Wave with micro-optimisers) and I'm so happy with it, I've got their new Energy Bank on back order. Will report back on how that goes when it turns up. However I know some people on here are vehemently against both SolarEdge and micro-optimisers, so to avoid making this a battle: the above is in no way a recommendation, just a statement of fact about my personal N=1 experience.

- @Nickfromwales is a strong supporter of the Solarwatt battery & BMS. That seems to work with Fronius inverters? I honestly can't find any useful tech info on www.solarwatt.com though - like it doesn't even state if it is AC or DC coupled. Presumably you need to be in the trade to get their install manuals / application notes, which doesn't bode well for a DIY install 😕

 

Installing the battery now saves on VAT so makes sense.

 

But whatever you do, expect supply chain delays.

 

[Nickfromwales]

1 minute ago, joth said:

But whatever you do, expect supply chain delays.

Yup, 12-15 even 18 months is about correct.

 

2 minutes ago, joth said:

- @Nickfromwales is a strong supporter of the Solarwatt battery & BMS. That seems to work with Fronius inverters? I honestly can't find any useful tech info on www.solarwatt.com though - like it doesn't even state if it is AC or DC coupled. Presumably you need to be in the trade to get their install manuals / application notes, which doesn't bode well for a DIY install 😕

The info is out there alright....  I've even posted links to it on here showing the sleep function. They do both AC and DC versions, just to confuse you even more lol. The DC is my favourite, as it allows you to load it up to the hilt without incurring the wrath of the DNO, eg allowing you to go to max allowance on PV kWp.

 

For completeness, I am personally going with Iconica Hybrid inverters with AGM batteries, as any "brand name" battery is overpriced / unrealistic economically in terms of RoI vs useful lifespan ( IMHO ).