I bought a lithium battery last year or so ,the cigar lighter connection was a pain in the arse,constantly coming lose while the dog was running,i eventually taped it up but not long after it broke inside it,so i connected the battery plug straight to the lamp,but it just keeps over heating and melting the connection to the battery,it's gone that bad now the plug will not go into the battery.they are great when they are working right but 200 euro for a battery i got one season out of ,is a pain in the arse,is this a common problem with them