I have a 1999 175 EFI (serial #0G944199) and if possible I would like to use a deep cycle battery as the starting battery because I also run my electronics off of the cranking battery currently and have started having problems with my depthfinder shutting off. I have asked about it and have been told that it's because the battery doesn't have the reserve capacity to run it all day. I don't have room for a 4th battery either. I have been told not to use AGM or sealed batteries because of the stator, but could I use a deep cycle without causing harm?