EcoDIY sub-urban self-reliance

10 panel solar PV generating system

We have recently upgraded the batteries with the old lithium-ion batteries from our Citroen C1 Evie electric car.  Even second hand these batteries are much better than the old lead acid ones.

We built our first Solar PV system in 2011 so prices quoted are not current.   We used:

 12 100AH deep cycle gel batteries (at £45 each from EBay) total £540

10 160 Watt Solar panels (From a contact found on EBay) cost £4000

A100C Import /Export meter (OFGEM approved) Cost £42 from Universal Meter Services

Morningstar charge controller SR740TL with remote digital display - (to charge the batteries from the solar panels)  from cost £246.

APC su3000rmxli3u rack mount UPS (un-interruptible power supply) from EBay to use as an inverter (a cheap way of changing the battery DC to 'mains'  240volt AC cost £187 (including delivery) highly recommended seller email:

I am using galvanised steel C studs to fix the panels to the roof saving about £400 on using aluminium section.  The brackets are table leg fixing brackets from a hardware store

I am a little disappointed in the efficiency of the battery based system which seems to be about 60%,  Systems which feed into the mains should be much more efficient (over 90% I believe)

The generating system we created is more economically justifiable because we are customers of Good Energy (electricity supply company) which is at this moment the only electricity company that uses only renewable energy sources (as far as I am aware).  Good Energy will pay us 9p a unit for all electricity we produce from our PV system plus 3p as a notional amount of 50% exported even though we are using the electricity ourselves and not exporting to the grid! They will also pay for solar thermal (water heating) per kilowatt hour if you are gas customers of theirs.  We missed out on the higher government FITs payments by installing before the payments came in.

 I have ended up a system costing a little over half what a mainstream company would charge for a similar sized grid connected setup.

A good helpful supplier for solar and wind components is Aire and Sun

I did have trouble finding DC connectors to fit those on the panels and ended up buying a different make from eBay and changing half of the connectors to the new ones (using a crimping tool from B & Q) by changing half the connectors I gained some spares to connect to the other half.  I found in line crimp connectors at a local electrical wholesaler useful to join cables together.  I sealed the joints with heatshrink tubing over each one.