[COLVERT]

Originally Posted by stocktake

The intelligent chargers will not charge a totally flat battery, I have got around this before by bridging to pos and neg poles with a pp3 9v battery with the charger attached, this fools the charger into thinking it is almost flat and it begins charging .
Or, if you have a 2nd charged car battery, you could try to fabricate a pos and neg lead from the 2nd battery to plug into the towing socket.

This is the way to get one of those so called smart chargers to co-operate and start charging your flat battery.-Great advice.--