I have a vivitar dvr390h which does not work by battery,however will work when connected to the mains,Bought what i thought was correct battery ,came on then cut off??
Hard to prove if you dont have test gear - I have bought some cr*p batteries myself but now check them on a multimeter and if necessary ask for refund - If you know anyone with a multimeter they will quickly check the battery alternatively ask your local camera shop to check it ( say you are thinking of buying a back up )
any decent cam shop will not charge you or press you to buy one unless you really need one
