Shed solar on a budget

[Joeboy]

Absolutely excellent, great read!

[AGT]

Update time.

1600w of longi panels on the shed roof, one panel left to be set up. I've reconfigured the westwards array to be flat on the roof of the other sheds down the side of the house. Shaded until after 1300, currently 1500w of panels connected to a £60 G83 Sunny roo inverter from ebay.

My hot water is now very hot thanks to the immersion running off the solic 200. We've had the washer on twice alongside baseload and my input CT showed 300w while the sun was shining.

I think I'm pretty happy. However I still have the other 410w of new panel and 750w of the older ones that aren't connected to anything yet. Sadly I think my old 700w microinverter has died, but I have two enecsys things and a 20A charge contoller that could play with some batteries....

Oh and I'm showing 100 kWH generated on the ketotek meter! £30 on our current tariff.

Great to hear it’s a success!

[drjim]

Just need to add up the cost so far for the solar payback target!

[nowty]

Update time.

1600w of longi panels on the shed roof, one panel left to be set up. I've reconfigured the westwards array to be flat on the roof of the other sheds down the side of the house. Shaded until after 1300, currently 1500w of panels connected to a £60 G83 Sunny roo inverter from ebay.

My hot water is now very hot thanks to the immersion running off the solic 200. We've had the washer on twice alongside baseload and my input CT showed 300w while the sun was shining.

Great feeling isn't it when you realise this stuff actually works, you have done it yourself and paid very little for it.

[drjim]

My growatt has done 8.1kw today, it has the fifth 410w panel on an optimiser connected, sun hits it around 9AM but cloud/haze and very intermittent today so only hit 2000w once. 8.1 is best yet.

The flat 2kw of old panels on the shed down the side of the house is shaded until about 2PM, but according to the inverter managed 5kw this afternoon. In the summer it will have less shading into the evening, so hopefully won't drop off as early - about 1730 today. Bear in mind this is £100 secondhand panels, a £60 inverter and mounted on bits of wood, £200 total cost.

All that pumped itself into the hot water tank, I bravely checked the programmer for the C/H. It was originally set up by British gas when they installed the boiler in 2010, I don't think we have changed the hot water side since then. It was running from 0600 to 1000, and again from 1500 to 2300, which guarantees a constantly full tank of hot water but suddenly helps me understand why our bills are so high. Set it to do 45min in the morning around getting up for work/school time and turned off for evening. Interestingly we still had hot water for showers at 10PM although my Wife said it wasn't hot enough!

Looking at my emonPi graphs, I can see when the solic is feeding the HWT the CT shows about 3-400w as import, I think/hope it's calibration and 300w is probably near nil. Just as I was leaving to go to work this morning the solar arrays were putting about 1600w into the house, we had the washer going, the immersion light was on and the power line on the graph sat at a steady 3-400 for hours. Dropped to around 150w in the afternoon when the sun hit the flat roof array and that cranked up over a kW. Dropped into negative for a bit after 4PM before the light tailed off.

So I think I have successfully heated my hot water tank from sunshine.

Only way I have to access the meter details is the loop app, which does seem to show us pulling in 300w plus. I will reset the solic on a day when the sun is actually shining for more than 5 minutes at a time and see if that changes. However our baseload is about 500w with multiple fridges, TV computer etc, so if I was pulling that while doing the washing and heating the water tank, it's OK

[Joeboy]

We use a solariboost unit and a switchbot remote finger (no joke) to time demand or spot demand on HWT charging. It has been an excellent combo allowing us a controlled use of large volume solar or letting the ct clamp sense the out going power and diverting to tank. Good for about 12kWh on a static day or up to 20kWh if kids are here.

Resonated with me reading this!

"All that pumped itself into the hot water tank, I bravely checked the programmer for the C/H. It was originally set up by British gas when they installed the boiler in 2010, I don't think we have changed the hot water side since then. It was running from 0600 to 1000, and again from 1500 to 2300, which guarantees a constantly full tank of hot water but suddenly helps me understand why our bills are so high. Set it to do 45min in the morning around getting up for work/school time and turned off for evening. Interestingly we still had hot water for showers at 10PM although my Wife said it wasn't hot enough!"

[openspaceman]

We use a solariboost unit and a switchbot remote finger (no joke) to time demand or spot demand on HWT charging. It has been an excellent combo allowing us a controlled use of large volume solar or letting the ct clamp sense the out going power and diverting to tank. Good for about 12kWh on a static day or up to 20kWh if kids are here.

I have had a bit of time with my Willis heater (Stinsy pointed me to it) as a way of utilising the surplus power from my 1800W of panels that charge my battery. The Victron charger has a relay that can be triggered by voltage and a timer which can hold the contacts closed to avoid short cycling. I supply 12V DC from a wallwart via the Victron relay and a bell wire to the Willis jacket. Currently it has a 2kW immersion element. The 12V from the bell wire triggers a 240V single pole relay which is in the feed to the immersion . The immersion master switch is a double pole.

It works well after a number of teething problems but the water is rather hot and it's a faff to extract the immersion element to alter the temperature as the element is at the bottom. To prevent the whole tank getting filled with over hot water I fitted a pipe stat on the feed to the Willis heater. I anticipate having to de scale the Willis at the end of the summer if not before. It is noticeably noisy and I wish I had fitted a 1kW element. I set it to trigger at 54.4V and stay on for 6 minutes. Today it triggered 10 times between 10:30 and 14:40 when the pipe stat was satisfied at ~40C. I had all the bits so it didn't cost any extras apart from the 16A pipe stat.

Scale and kettling are the drawbacks ( Willis are not recommended for hard water) and part of the reason is that the water at the top of the Willis is constantly being pushed up by cold water from the bottom of the DHW tank which cools the thermostat, hence the water gets above the temperature the thermostat is set at (70C). I am considering putting a 20A rated diode in the feed but not sure how the inverter would cope with that, else I will look out for a 110V site transformer.