1996 Johnson Evinrude "ED" Electric Outboards Service Manual, P/N 507119, Page 19Get this manual
Battery Recommendations Regular service batteries have been designed and optimized to supply the high current for short periods that is needed to run the starter and crank an internal combustion engine Deep-cycle batteries or dual purpose StartingDeep-Cycle batteries have been designed and optimized to supply smaller current for longer periods, and discharge further, using large percentage of their available power on regular basisAll electric outboards should use one or two marine deep-cycle batteries with rating of at least 80 ampere hoursUsing starting-type battery is not good economic choice, but if marine deep-cycle battery is unavailable and you temporarily substitute conventional marine battery, select one with rating of at least 515 CCA 00 (93 amp hrs-180C) with 165 minute reserve (80 F)The reserve minutes is the important rat ing for this applicationProvide separate battery(s) for the electric outboardIf 1224 volt electric outboard and gasoline outboard must share battery, the gasoline outboard must be connected to the number two battery to avoid severe damage caused by galvanic corrosionRefer to Battery Connections in Section 1, and wiring diagrams at the end of Section and Section 3Battery Testing