Was using my pure freedom trolley the other day and just went off on its own twice. Thought nothing of it .Then the day first house did the back and then went round the front and it had switched itself of and it wouldn't come back .Back home put it on charge and it was 12.4 so fully charge and away it went used for a few hours and seemed okay ,It will be about three years old .Any ideas what it could be ,Cheers