| You can buy halogen downlighter kits from any DIY place, like B&Q, and these will all run off 12v. You normally get a voltage converter with them so you can wire it up to the mains.
Either get some loose fittings and bulbs, or buy a kit and throw away the converter.
Last set I bought was 12.99 from B&Q for 3 downlighters and the transformer.
I think some of the bulb are rated as low as 6VA, so equivalent to a 50W bulb, and should last a while off a car battery. You'd probably need to recharge the battery every time though, but would be easier and give more light? | 
antonye
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