Topic: 77 750 SuperSport Battery Dead

[reliv77]

On my last ride the Battery slowly died on the way home. Newish Battery. How do I check if the Alternator is Charging? What else to check?

[Bankerdanny]

Start the engine and attach a volt meter to the battery then watch the voltage as you rev the engine up to 3-4k rpms. At near idle speeds the voltage will likely be around 12, but as you get to highway speed rpms the voltage should rise to 13.5-14. Anything under 12.5 or so at speed and you may have trouble maintaining a charge on your battery depending on the ignition style, coil type and any electric accessories you might have.

[calj737]

A bit simpler method...

Use a multimeter and take a reading directly at the battery, key OFF. Then key ON. Then with motor running, eking at idle, read the voltage. Raise the RPMs to 3,000 and take a reading, and then finally at 5,000. You can do this sitting in the garage, driveway, parking lot, wherever you have access.

If you post those readings, we can likely point you to the next step with clearer advice to help diagnose a problem you might have.

[reliv77]

Thanks for the replies. Charging the battery overnight to see if it holds a charge. Try troubleshooting tomorrow.

[Bankerdanny]

A bit simpler method...

Use a multimeter and take a reading directly at the battery, key OFF. Then key ON. Then with motor running, eking at idle, read the voltage. Raise the RPMs to 3,000 and take a reading, and then finally at 5,000. You can do this sitting in the garage, driveway, parking lot, wherever you have access.

If you post those readings, we can likely point you to the next step with clearer advice to help diagnose a problem you might have.

How is that different from what I said?

[b52bombardier1]

Don't forget to flip the multimeter knob to AC volts after you check the DC volts measurement.  The check for AC volts will give you an indication of the health of your rectifier.  Hope for no more than maybe a half a volt AC to maintain the health of your battery that loves DC - very much AC will kill a battery pretty quickly.

Rick