Friday, August 30, 2013

Inverter off again

29 Aug 2013: After a day, I had to turn it off as the Inverter was making an alarm call, the TV was off, and the web-router off too.... seems that the battery doesn't hold enough charge to survive even a day. I don't know what to do now... the PV panel is bought and installed... so is the next thing to buy a conventional lead acid battery?

Tuesday, August 27, 2013

Inverter running now

27 Aug 2013: I have, very cautiously connected the battery to a load. It has had three days of charging slowly from the single PV panel, days of mixed cloudy bright conditions. The battery rose from a starting voltage of 11vDC to 13.6vDC.
   I have started using it by running the water pump that operates the evacuated tubes, 72W power consumption. This consumption occurs when there is sunlight or brightness in the sky, so the 200W PV panel should be able to meet this load.
   If the battery is happy after a couple of days, I will add more load by connecting more appliances, e.g. another of the waterpumps.
   The regulator is quite good in displaying the current battery condition, and it allowed the battery to rise in voltage to 13.6vDC which is something the car charger did not allow. Once it is working under load, it levels to an equilibrium of 12volts.
   One thing I have added to the group of appliances is the TV aerial amplifier in the loft. This means that when my wife complains that the TV signal has suddenly gone weak, I know that I need to go into the loft and see what is happening...


Perhaps in winter, I will need to connect the appliances to the mains, as before.

Monday, August 26, 2013

August 2013 Reports

26 August 2013: Weather continues to be warm and dry, so different from a year ago.
  • House annual 5,407, biennial 5,223 kWh. 
  • GSHP annual 3,420, biennial 3,206 kWh, triennial 3,243 kWh. No change.... steady... 
  • PV annual 3,133, biennial 3,093 kWh, triennial 3,176 kWh. Slowly improving change.... 
  • Sunbox annual 3,120, biennial 2,839 kWh. Sunbox energy capture still improving, I wonder what the new top line will be. It is the combined figure for the two sunboxes, and does not include the tubes. 
  • Ground Temperature 13.5ºC. This seems to be a consistent summer temperature. 
12 August 2013: The nights are getting cooler and we have had hints of Autumn already! It's been a good summer though, compared with 2012. The days have been a mixture of overcast with sunny spells, but not much rain.

  • House annual 5,417, biennial 5,210 kWh. No change..... 
  • GSHP annual 3,427, biennial 3,202 kWh, triennial 3,244 kWh. No change.... steady... 
  • PV annual 3,102, biennial 3,096 kWh, triennial 3,166 kWh. No change.... steady... 
  • Sunbox annual 3,024, biennial 2,789 kWh. Sunbox energy capture is improving (with the help of the ETFE front panels), it has now gone past the magic 3,000kWh point! 
  • Ground Temperature 13.6ºC. This seems to be consistent temperature, there's been no significant withdrawal from the borehole store, but there must be some diffusion of the energy outwards.... until the heating season starts!

Sunday, August 25, 2013

PV Panel connected up

24 Aug 2013: I've been back to Maplins for the more powerful regulator and that is now up and running - charging the bank of Nicad cells.
A double light switch is used as an isolator for the panel and for the line to the battery. It is super important to get the positive and negatives correctly wired up - check, double check before starting it up!There are 80 1.2 volt NiCad cells riveted together in lines, and in parallel to form a 12volt battery. Let's hope this works.
I will not draw any load off this yet, until it has had another day of charging from the panel.

Saturday, August 24, 2013

PV Panel up but not regulated

23 Aug 2013: The PV Panel for the house extension is now mounted and the DC cables are threaded through the vertical duct. It is not working yet because the regulator I got for it is not up to the job, and I should have realised this as it was a cheap Maplins one. This one is for a low powered device like a caravan solar panel or wind turbine. At the moment, it is 40v DC in, and 40vDC out.... should be 40vDc in and 12v DC out for the connection to the battery.
     Maplins also do a regulator for solar panels up to 500w. This panel is only 200W, so I now need another trip to them to get the more powerful one.

Getting the PV panel ready to lift - it is only 15 kilos, so the biggest worry is how to avoid scratching the surface while handling it.The PV panel in place. Held down with only 3 clamps, I need one more M8 50mm bolt to hold down the fourth.
The panel is delivering a healthy 40 volts plus, but I can see that there is room for improvement, already even though it is not connected. The photograph shows two shading hazards straight away.

  • The solar-thermal panel next to it is 200mm higher so there is a shading hazard as soon as the sun moves to the West after 2pm.
  • The garden fence is an open grid, but that is enough to cause a shading hazard in Winter. The roof angle is 15º, and the maximum winter sun angle is 15º the other way, so there isn't going to  be much gain. With the shadow from the fence it will be even worse. 
However, I could build four aluminium legs and elevate the whole panel by 200mm. Another little building project on the way. It will also improve ventilation underneath the panel (marginal improvement in performance in hot air temperatures).

Sunday, August 18, 2013

Another PV panel coming

17 Aug 2013: There is one more space on the east end of the roof of the extension. Today, I had delivery of a single PV panel, 800 x 1600. It has to be narrow to fit the space remaining. It's been delivered by Chris Wheelwright of Solarheat UK, a Nottingham installer, but as it is not going to be Grid-connected, it's going to be my job to install it. 

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