Had this problem before few years back and think we trashed the lamp and bought a new one on that occasion... For no apparent reason this lamp has suddenly decided it is going to consume a lot more energy than it did before and is nothing to do with the batteries themselves. The bulb clearly is not blown as still illuminates but will chew through fully charged batteries in approx 10mins instead of usual 1-2 hours. Is it possible these bulbs get to end of their efficient life without actually stopping illuminating?