Thread: Parallel Battery Question

You can but not good to mix different kinds of batteries. Weak on going to pull down stronger one. Have to disconnect to charge, they will be different charge rates and other issues. I would just replace cranking battery with one of the newer deep cycle batteries designed to be used for cranking and cycling. I have been using a straight deep cycle for cranking battery for years with no problems with older motor, no fuel injection. Caftan put up a good thread recently that really cover batteries very well.