Hello, Would you confirm if the B+ output of the E30 battery charging circuit is electronically regulated to suit deep cycle charging or if it strictly a starting battery charger? Thanks.
The battery charging output(s) of all ETEC outboards utilize a constant voltage charging system. This means that as the battery accepts charge and the cell voltage rises, the charging current will diminish.
The charging system is not necessarily optimized for any particular battery chemistry/construction but is a widely accepted method of safely charging a lead acid battery in a reasonable quick time span.
Based upon my knowledge, a deep cycle battery charge requirement is not that different from a cranking battery. Maximum charging current should be within the guidelines recommended by the battery manufacturer. Other charging modes such as float charge and equalization will aid in obtaining the maximum possible energy capacity of a battery and promote the longest possible battery life. The engine's charging output does provide these modes. Likely the biggest issue you will face is undercharging of batteries due to prolonged drain of the vessel batteries and limited engine run time to provide recharge. In the interest of battery life, it would be best to provide shore charging of your batteries after each use with an automatic type charger.
Elder Sparky is correct, of course. Your charging system is designed for traditional flooded cell batteries, low maintenance batteries, and for AGM sealed styles. Do not use Lithium batteries with your engine.
"There is never just one thing wrong with a boat";
-- Travis McGee, main character in a book series by John D. McDonald
The factory recommends that a properly trained technician service your Johnson or Evinrude outboard motor. Should you elect to perform repairs yourself, use caution, common sense, and observe safety procedures in the vicinity of flammable liquids, around moving parts, near high-temperature components, and working with electrical or ignition systems.
The information offered here is only general in nature and should not be construed as complete factory approved procedures, techniques, or specifications. Always use the proper service manual for your motor, up-to-date service literature, the correct tools, and have an understanding of how to proceed with troubleshooting and repair methods. If you are unsure or uncomfortable with a procedure, a situation, or a technique, enlist the services of a factory trained technician.