This just in from Andrew Marx.
"Have just ordered from Maplin (mail order catalogue delivered with the Telegraph) for £7.99 a solar powered charger for batteries. It says it is for 12 volts but under FAQs says it can also be used for 6 volt batteries. It might be useful for those of us whose dynamo does not work on long days out? The website is http://www.maplin.co.uk - will report on result."
Solar battery charger
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