Second system extension extension.

Stan
Posts: 377
Joined: Fri Jun 11, 2021 10:45 am

Re: Second system extension extension.

#121

Post by Stan »

You’ve got a serious amount of PV there Tinbum, not to mention battery storage. Are you earning FITs on that or even just on your house?
My mind wanders to having another array, a big one with storage. At present I don’t know enough about how it would island alongside my domestic system and whether I would be risking the existing FIT payments.
Tinbum
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Joined: Mon May 31, 2021 9:55 pm

Re: Second system extension extension.

#122

Post by Tinbum »

The pylon have still to be connected so just running on the lead acid at the moment. I need to concrete a floor first for the batteries but I'm still suffering from Long Covid and haven't had a day when I could contemplate doing it. Fits are just on 2 arrays of 4Kw and the rest I keep separate and off grid. I've another 16Kw to go up but the old roof needs new sheets first. The plan is to be totally self sufficient in energy in the end.
85no 58mm solar thermal tubes, 28.5Kw PV, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, 8kWh Growatt storage, 22 x US3000C Pylontech, Sofar ME3000's, Brosley wood burner and 250lt DHW
Stan
Posts: 377
Joined: Fri Jun 11, 2021 10:45 am

Re: Second system extension extension.

#123

Post by Stan »

That’s what I don’t understand yet. How do you use the power from the off-grid system without affecting the domestic system?
Tinbum
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Joined: Mon May 31, 2021 9:55 pm

Re: Second system extension extension.

#124

Post by Tinbum »

Use the off grid system all the time for pretty well everything and then use the on grid for specific things eg heating DHW, dumping to central heating and then battery chargers to charge the off grid system.
85no 58mm solar thermal tubes, 28.5Kw PV, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, 8kWh Growatt storage, 22 x US3000C Pylontech, Sofar ME3000's, Brosley wood burner and 250lt DHW
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nowty
Posts: 5793
Joined: Mon May 31, 2021 2:36 pm
Location: South Coast

Re: Second system extension extension.

#125

Post by nowty »

I was similar to Tinbum, I used to have roughly half my system as an off grid system to get around the max 3.68kW rules and I would switch selected house circuits between grid and off grid using a patch panel of plug and sockets (no suicide plugs !) and a change over contactor based upon battery SOC. It got pretty complicated, so eventually I re-designed it with the newer G100 export limitation technology when I upgraded to a newer SMA Sunny Island. The system is now far simpler and I can edit settings with a webpage, shame my thread had to die on the old forum with details of all the changes.

The Octopus Go, Go Faster and now the Octopus Intelligence tariffs have made my life even easier as it rivals gas cost on even resistive storage heaters overnight and running my small heatpump on the batteries during the day.
18.7kW PV > 109MWh generated
Ripple 6.6kW Wind + 4.5kW PV > 26MWh generated
5 Other RE Coop's
105kWh EV storage
60kWh Home battery storage
40kWh Thermal storage
GSHP + A2A HP's
Rain water use > 510 m3
Tinbum
Posts: 1119
Joined: Mon May 31, 2021 9:55 pm

Re: Second system extension extension.

#126

Post by Tinbum »

Using something like a Lux or Growatt can make it really simple as they could divert all the AC from the grid system to the off grid system batteries. No need for any AC loads on the grid.
85no 58mm solar thermal tubes, 28.5Kw PV, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, 8kWh Growatt storage, 22 x US3000C Pylontech, Sofar ME3000's, Brosley wood burner and 250lt DHW
Stan
Posts: 377
Joined: Fri Jun 11, 2021 10:45 am

Re: Second system extension extension.

#127

Post by Stan »

Thanks Tinbum, Nowty. I hadn’t realised how radical it would be but it makes sense.
What is the G100 export limitation technology?
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Stinsy
Posts: 2852
Joined: Wed Jun 02, 2021 1:09 pm

Re: Second system extension extension.

#128

Post by Stinsy »

The interesting point is that even if you have an off-grid setup, you can still charge the batteries from the grid on days when there is perilously little solar.
12x 340W JA Solar panels (4.08kWp)
3x 380W JA Solar panels (1.14kWp)
5x 2.4kWh Pylontech batteries (12kWh)
LuxPower inverter/charger

(Artist formally known as ******, well it should be obvious enough to those for whom such things are important.)
Tinbum
Posts: 1119
Joined: Mon May 31, 2021 9:55 pm

Re: Second system extension extension.

#129

Post by Tinbum »

My grid charge last night at 8A per phase.

Image
85no 58mm solar thermal tubes, 28.5Kw PV, 3x Sunny Island 5048, 2795 Ah (135kWh) (c20) Rolls batteries 48v, 8kWh Growatt storage, 22 x US3000C Pylontech, Sofar ME3000's, Brosley wood burner and 250lt DHW
User avatar
nowty
Posts: 5793
Joined: Mon May 31, 2021 2:36 pm
Location: South Coast

Re: Second system extension extension.

#130

Post by nowty »

And my setup yesterday 18th Oct, the Solar generation was forecast to be very bad so I set a 2kW charge for the batteries from the grid during my 5p / kWh 23:30 to 05:30 cheap slot. Also during cheap slot, ran the storage heaters, heatpump for hot water tank and heated floor in kitchen. The regular spikes during the day were for my heatpump running the house heating from the battery bank and a bit more around 18:00 cooking the roast chicken dinner.

Image


And my Octopus Smart meter import for the same day from my Octopus account, out of the total imported leccy of 40.906kWh, only 0.095 kWh was at peak rate. I note there is a slight difference between my SMA energy meter reading and my smart meter reading, don't know why but happy that the smart meter total is lower. :mrgreen:
Image
18.7kW PV > 109MWh generated
Ripple 6.6kW Wind + 4.5kW PV > 26MWh generated
5 Other RE Coop's
105kWh EV storage
60kWh Home battery storage
40kWh Thermal storage
GSHP + A2A HP's
Rain water use > 510 m3
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