Has any one got any recommendations for the battery powered ones?I've had 2 lots of 3 now and the battery life is awful.They weren't overly expensive but still I thought they'd last longer than they have.Its costing a small fortune with 3 batteries in each light and I dont seem to have them on for that long.Have looked at some reviews online but just as I find some with good reviews someone further down says "battery life rubbish" .Are they all just crap?!