On Sat, 22 Aug 2009 21:49:14 +0100, "DIY" wrote:

If the battery connects straight to the socket you'll need a suitable
charger, not a gen purp wallwart.

As stated in my original post I have got a regulated DC adaptor that can be
set from 1.5 to 12volts with either a positive or negative tip, and which I
have since used to charge both lanterns at 6volts. What is a wallwart?

What you're describing, if it looks like a pregnant 13-amp plug :-)

If there's no charging control circuitry in the appliance you'll just
have to make sure you don't leave it connected too long. A proper
charging system would be kinder to the batteries. But I wouldn't
worry too much. It's only a gadget, not the backup power supply to a
life-support system.