When setting up a Honda BF8D, BF9.9D, BF15D or BF20D, choosing the right battery is essential for safe and reliable operation. Electric-start outboards ship without a battery, so this is the first rigging decision a new owner makes. Whether your model features an electric starter or a manual start, Honda specifies clear requirements in the owner's manual.
Battery Specifications
All Honda BF8D, BF9.9D, BF15D, and BF20D outboard motors operate on a 12-volt system. For electric-start models, Honda publishes a minimum battery capacity (Ah) and cold cranking amps (CCA) rating in the specifications section of the owner's manual for your model year; treat those numbers as the floor, and go larger if the boat runs lights, a fish finder or other accessories off the same battery.
Types of Batteries
Electric-Start Models
- These outboards include battery cables — a red-banded positive (+) and a black-banded negative (–) lead. Use a high-quality starting or cranking battery, not a deep-cycle type, as deep-cycle batteries are not designed to handle engine starting loads. Our battery cable and wiring guide covers cable gauge, terminal hardware and routing, which apply to any small outboard.
Manual-Start Models
- A manual-start motor does not need a battery to run. Some Honda models can be fitted with a charging output to keep a battery topped up for lights or electronics; check your owner's manual or ask us whether your model year has it or can be equipped with it.
Installation and Safety Tips
Always use a corrosion-resistant battery box and mount it securely in a dry, ventilated area away from heat and direct sunlight.
The charging circuit is protected by a fuse under the cowling; if the battery stops charging, check it before suspecting the charging coil.
When working around batteries, wear eye and skin protection — the electrolyte inside contains sulfuric acid, which is highly corrosive.
Keep children and untrained individuals away from batteries.
Minimum Requirements
Voltage: 12 V
Type: starting (cranking) battery, not deep-cycle
Capacity and CCA: the minimums printed in your Honda owner's manual
Not sure whether electric start is worth the extra cost on a motor this size? Our guide to electric-start outboards weighs it up, and if you run a Suzuki instead, the Suzuki battery requirements chart lists the published minimums by model.