Charge A Battery On A Harley Road King

Charge a Battery on a Harley Road King

The battery in your Harley-Davidson Road King should rarely need recharging because the battery tender should prevent the battery from dying. To recharge the battery, you can use jumper cables and a car’s battery. Some mechanics advise against it, but Harley manuals offer instructions for the procedure. The concern some mechanics have is that the donor amperage will be too high for the bike’s battery. However, motorcycle batteries have improved over the years and this is much less of a danger. One precaution further minimizes risk to your battery: not starting the donor vehicle during a jump.


1. Check that the battery of the donor vehicle is 12 volts, like your Harley’s. Otherwise, you can fry your electronics.

2. Turn off your Harley’s headlight, radio and all other electrical components.

3. Move the vehicles close enough to connect them with jumper cables, but not close enough to touch and cause a misgrounding.

4. Turn off both vehicles’ ignitions.

5. Remove the motorcycle’s seat to gain access to the battery.

6. Put on protective gloves and safety glasses.

7. Attach one of the two red jumper cable clamps to your Harley battery’s positive terminal. Attach the corresponding black cable to the Harley’s negative terminal.

8. Connect the unattached red clamp to the donor vehicle’s positive terminal and the corresponding black clamp to an unpainted piece of metal at least 18 inches from the battery and also away from the engine. Clamp it, for instance, to the edge of the body panel. Do not start the donor vehicle‘s engine.

9. Let the donor battery charge your Harley’s battery for 15 minutes. Leaving the jumper cables in place, start your Harley.

10. Let your Harley run for 15 seconds before disconnecting the clamps in the reverse order in which you connected them. Let the bike idle for a few minutes before riding off, so the battery gets better charged.

11. Remove the battery later and recharge it fully with a 3-step recharger with low amperage (2 to 4 amps preferably). 3-step rechargers are best because they fully recharge the battery.