I have the mk335pc that i bought about 4 months ago and batteries seem to be charged ok, but i notice that the green lights for all 3 batteries (1 cranking size 27 and 2 x size 31 trolling batteries) stays solid on more than blinking. Boat is parked in garage and i check almost daily and they are rarely blinking. Is this normal? or is there something possibly wrong with the unit or batteries?