We have got one, not an expensive one, it runs on a 9V battery, can't remember if it says not to use rechargeable batteries or not, but I can check for you, if you are interested. We haven't had it for very long so not really used it very much. We did however take it on holiday with us last week and used it one day for most of the day on and off and the low battery light hasn't come on. We also weren't very successful in finding much, we did find a 20p piece buried in the sand by Mr Jules, some metal bottle caps and a rusty piece of iron. We just used it as a bit of fun rather than serious hunting, although it would have been nice to find something worthwhile. We weren't really sure where the best place for detecting was either, as the tide went out, the sand was obviously wet and any holes dug just filled with water so a bit non-productive and up near the cliff edge just found beer cans and bottle tops.