Nothing wrecks a lead acid battery quicker than sitting around for long periods partially discharged, this causes sulfation of the lead plates where a crystalline forms on the plates reducing the area for the sulphuric acid to work on the plates effectively , for infrequently used vehicles a battery minder is a must for extending the life of the battery ,all my vehicles are hard wired with quick couplings to attach a battery minder with capacity to suit the vehicle 350ma,1600ma and 5400ma units all with automatic cut offs and suitable voltage ranges,