After considerable discussions, we have decided to take the plunge and invest in some Green Energy solutions. We have ordered seventeen electric solar panels, measuring 2metres by 1metre high, rated at 405Watts per panel. This power rating isn’t set in stone as you can imagine when we got something like our Sun that keeps moving around, hazy skies, rain and the occasional solar eclipse producing shadows and affecting what power we can generate. The solar panel manufacturers all have to measure their panels using a standard 1000Watt testing rig but they also have to quote a so-called realistic figure as if we only got 800Watts per square metre, so these ratings that they have printed on the panels are only a guide and we could indeed, on rare occasions, get more!! But, big sigh, our Good Old British climate, we will likely only get 300 to 350Watts per panel on a very very clear blue sky day.
So with our seventeen panels, seven on the P roof (overlooking our Patio) and a further ten on our M roof (overlooking our swimming lane), we could be producing 5 or even 6kiloWatts on a good bright sunny day when the Sun is right overhead. Otherwise, we would generate about 2kiloWatts on our P roof in the morning times and then 3kiloWatts later on in the afternoon and evening. We expect to generate about 10,000kWh per year.
We ordered the panels from a UK stockist because the country now imports so many panels that it is not cheaper to buy direct from China these days. Hopefully, we will get those in a week or so.
Another collection of items that we have ordered, is the mounting brackets and bars for fixing our solar panels on our roof, going through the slates but maintaining a waterproof seal etc. That is quite complicated shaped pieces of steel & aluminium and it costs almost as much as the solar panels for that mounting hardware.
Next, we did go direct to a Chinese supplier for our batteries. It is not so common .. yet .. in this country, or rather, the batteries are being packaged into a single product and sold including installation fees added on top and it is many thousands to get hold of that type of batteries and the associated electronics. But, we like to do things ourselves but also, mostly, because we are wanting a much larger battery capacity and no one does a bigger system for a sensible price. So we are ordering 36 “cells”, each rated at 280 Amps Hour at 3.2Volts, measuring 72mm thick, 225mm high and 174mm long. They are about a third of the width of a typical car battery with both of them having about the same power capacity, which is amazing especially considering that they are much lighter and also have very good number of discharge and charge cycles. We are building two 50Volt battery sets, each having 16 cells, giving us about 30kiloWattHours capacity and one 12Volt set with four cells giving us nearly 4kiloWattHours. Each set will have a management computer overseer, to keep an eye on each separate cell and also the whole overall performance as well, protecting the batteries from any short circuits and other faults that may develop and shut the whole set off just in case. These computers are rated at 200Amps. The shipping will take six to eight weeks so sometime in late August or September.
Another piece of equipment we ordered is a 5Kw hybrid inverter that takes two strings of electric solar panels and transforms those strings into both mains electricity to use generally and 50Volts to charge the two battery sets.. The box will take the power from the solar panels and either provide it as 240V mains electricity for general use and when the house is not using all of the power it will charge the batteries. If the house need more mains electricity than the solar can provide then the box will use the batteries to add extra output. It can be programmed to respond in various ways, depending on our requirements. This box will also act as a battery backup and will power our critical mains electricity usage (up to 5kW) if we have a power cut
This is a major step for us to be taking right now, but, we really need to do something to help us avoid much of the enormous price increases we all are facing! But, we had always had plans to install solar panels, it is just coming much sooner than we thought, and the batteries have become much more affordable these days and be able to pay off the investments quite quickly.
Spending less than £10,000 now will give us enough free power to mean that yearly electricity bills will be tiny for 20+ Years to come!