Can anyone tell me what's gone wrong please ! Since my motorhome had sat unused for a while and had a flat battery, I had to start it with a heavy duty battery charger set on the start boost position. I took it for a run some 60 miles and stayed at my daughters overnight without electric hook up. The next morning it did not have enough charge to start up, so I used the boost start again to get home. Since then it has been on fast charge for 3 days and trickle charge for a further 24 hours. The fast charge should automatically drop down to trickle according to the charger spec. I reconnected the negative terminal and tried unsuccessfully to start it. Instead of the usual dull click of a flat battery the dashboard lights flashed and continually clicked in a noisy and alarming way. I checked that the negative terminal was connected properly, which it was, and tried again. The same flashing and clicking ensued so I disconnected the negative terminal in case any further damage was caused. Can anybody tell me what may have happened and what I do next please. Denny.