The Medway Handyman explained on 02/05/2009 :
A) Our lights will not charge indoors under a lamp with artificial lighting.
They need to be placed outside in direct sunlight to charge. Before packaging
lights the batteries are tested and 30% charged. We recommend placing
allowing up to full 3 days of sunlight to fully charge the batteries before
initially using the light.

How does that work then? I thought light was light?

Shine even a 500w flood on a wall in broad daylight and you would have
some difficulty in telling if the lamp was on or not - all due to how
dim lamps are when compared to sunlight. Hence the photocells need the
sunlight hitting them to produce any useful output.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk