Batteries for Outboard Engines are unique and great care needs paid to what battery is used – otherwise, you may ruin your entire engine before you know it. It’s the Technician’s job to educate boaters, so here are some tips to help you do just that.
QUICK TIPS & SUGGESTIONS
The minimum specification is for the motor alone, and does not consider other electrical requirements on the boat. Good rule of thumb is to add 20% to Mfg. Recommendation.
Quickest Testing Method
For a fully charged battery, the quickest test method is to crank the engine for approximately 15-20 seconds, with the ignition disabled. The battery should stay above 10.5 V if the engine is in good health and of proper capacity.
On today’s digital electronics, over voltage can trigger shutdown or activate alarms. Avoid this by installing a heavier duty battery or install a second battery in parallel with a switch.
It is suggested to clean and secure battery connections, use lock washers & hex nuts tightened with a wrench, & Clean and spray connections with a non-hardening electrical sealer for protection.
CCA Cold Craking Amps = Maximum current output when tested at 0° F for 30 seconds.
MCA Marine Craking Amps = Maximum current output when tested at 32° F for 30 seconds.
RC Reserve Capacity = The number of minutes a battery can deliver a constant 25 Amps until voltage is decreased to 10.5V.
Group 24 is the most common marine battery size.
Starting – Designed for quick bursts of power, but if operated below 50% discharge, life is severely shortened.
Deep – Cycle – Designed for long term, low current draw, but are not designed for quick bursts of power.
Combo Start / Deep-Cycle – Designed to combine quick bursts of power & long term, low current draw.
Flooded-Cell – Designed to tolerate higher charging voltages.
Maintenance Free – *NOT RECOMMENDED for Marine Engines* Designed to minimize gassing during recharging, but are subject to early failure if the charging voltage is not regulated.
AGM – Designed to last long term, as long as they are not discharged below 50%.
Gel Cell – Designed to be very good for deep-cycle use, but very sensitive to charging currents & voltage limits.