I guess most houses these days that install solar panels are already wired for mains electricity (240 volt AC in Australia) and therefore have to install a big inverter to power their house. I built my house from the ground up and chose to install low voltage cable throughout, and intended to run everything straight off 12 volts from the solar panels and a battery bank. I did not intend to put $20,000 or $30,000 worth of solar panels in, but the bare minimum – I have three 100 watt panels and nine 120AH batteries (and a wind generator).

Initially I installed 12v halogen downlights because they are already 12v – but they draw a huge amount of current which flattened my batteries fairly quickly. Particularly in winter when there is less sun anyway (shorter days) and the lights are being turned on much earlier each evening. At one stage I had one light on, and used half a dozen candles around the room to provide more lighting – these yellow candle lights did give a nice warm glow to the room, but you really couldn’t read or do much till the next day when it was daylight.

Then a year or so later I found some 20 LED replacements for the halogen lights – I think they were about $20 each. If you sat directly under one of these it was just barely good enough to read by. About this time I also found some 18 LED kits to build and I made a few of these and used them in various bed and table lights.

  From this to this   

A 50 watt halogen would draw over 4 amps at 12 volts, and a 20 watt would draw over 2 amps. The 20 LED would draw 0.1 amp – a huge improvement in saving power, but not very satisfactory for good lighting. So where-ever I had one halogen, I put three of the 20 LED lights in.

   Bedlamp.

Then another year or so went by and I found a 36 LED replacement for the halogens fittings. These gave much better light than the 20 LED lights, but were $40 each. Why would you spend $40 per light? Well it was either that or put two more solar panels in, and maybe more batteries, to be able to run halogen lamps. A one hundred watt solar panel is $1,000. So spending a few hundred dollars on lights was still cheaper than more panels. These lights were a vast improvement, and you could read a newspaper directly under them – they were quite narrow beam.

 36 LED

If lighting never improved past these, this would have been just satisfactory.

However, I have now been buying a new light. It is 1x MR16 bulb with 3 x 1 watt CREE LED that can fit your 12 volt halogen fixture. These put out as much light as a halogen globe – as far as the eye can tell, and they are wide beam. They draw just under 0.3 amp at 12 volt. These are the answer to my prayers – a light as good as a halogen, but a 20th the current. One slight problem – they are $70 each from Jaycar. Just a while ago they were $60 each – so much for solar stuff getting cheaper. But I had to have some, quite a few actually. I found them online in the USA for A$41 each – much better –almost half Jaycar’s price. Which is a bit strange because they come out of the same factory in China. I got 10 of these from the USA for A$27 postage, which makes them about A$44 each, still way ahead of Jaycar. They were here in 7 days.

 3LED CREE

So if you want to get some absolutely brilliant halogen lamp replacements try
http://www.ledwholesalers.com/store/index.php
They have a huge range of other LED lighting.

I did email them first to ask about postage, because their website only has expensive UPS delivery on it. They quoted me US$20 first class mail, and said they would refund the difference. I got $71 refunded within 24 hours of ordering (the UPS was US$94).

I also bought from them some bedlamp replacement LEDs.
        

You would not believe how bright these are – far brighter than my 18 super brite LEDs, and a much wider beam as well. These are 6 surface mounted LEDs, and they also have the same thing with 10 surface mounted LEDs if you want more light.

One note of warning about using the CREE lamps – they have an aluminium body. Some of my fittings used these connectors:-

Part of the metal bits come up above the top of the base, and will short out on the aluminium part of the CREE.

You need to make sure the fittings are this type, or cut a small rectangle of cardboard and poke the pins through.

I have a workshop, and a garage, that as yet do not have any lighting whatsoever, so the lights that have been replaced will eventually go into these areas just to give overall illumination.

The other thing I have found recently are compact flourescent globes that run directly off 12 volts. The only trouble was that I couldn't get any mountable sockets to screw them into. This called for some modification. I smashed the glass out of an ordinary light globe to get the bayonet fitting from it. Drilled fine holes through the two contacts, and soldered two wires onto the small screw base of the compact light. These poked down through the holes in the bayonet fitting and were soldered. The bayonet fitting was then partly filled with epoxy glue to secure the screw compact into it.

Then I attacked the halogen downlight fitting, and mounted a normal 240v bayonet socket in it at just the right spacing to let the 'new' compact fit into it neatly. (Incidentally, you can buy 11 watt 12v compact fluorescent lights that come with a normal bayonet fitting - but these are only equivalent to a normal 60 watt globe. I wanted more light than that)

This one is 20 watts, equivalent to a normal incandescent 100 watt globe. They draw 0.8 amp at 12 volts - not quite as good as the 3 LED CREEs, but give a great all-round light for a big area.

I wonder how many people are installing solar panels to reduce their electricity bills, OR to do something for the environment. If the latter, then unless they are also installing batteries they are kidding themselves. Most people seem to be not installing batteries, and selling excess power to the authorities during the day, and buying it back at night. Think about it. The authorities can't store your power during the day - they don't have batteries. So at night the authorities are providing you and all your neighbours with exactly the same amount of power as they were last week, last month, last year. As more and more houses get built, the authorities will need to build more power stations to keep up with the night time demand. This is crazy. Get yourself disconnected from the power grid and be self sufficient if you are serious. And don't be surprised if the generous renumeration you are getting for the power you are selling them during the day isn't reduced considerably at some future date - this is at the whim of the company. If they decide next year to pay you slightly less, and to charge you slightly more for the power you buy back from them, then the sums you did on how long it would take to break even are going to be wrong - it will take many more years before you start to save money on your power bills. If everyone disconnected from the grid we could get rid of those unsightly power lines, and the power poles that seem to attract vehicles now and then.