Battery showing 18+ volts?! (check your multimeter)

[Zwerski]

Heading out on a 3-day trip tomorrow. Refreshed my battery overnight and just went to test voltage - it shows 18.75 volts off the bike (removed to check electrolyte levels). I have time to source a new one, if needed. It's a Napa GS 10L-A2 lead acid that was on the bike when I hot it used two summers ago. It's ridden regularly and stored on the battery tender when not used more than a month.

[Zwerski]

FFS. Whelp. New bike battery not needed. Crisis averted. What DID need a new battery?

My multimeter. Never have replced the battery the entire ten years I have had it. So, lesson learned. New 9-volt installed and all systems tested within range: battery, Battery tender and charging system.

Lesson learned.

[adidasguy]

18v? Was it on a charger? If so, your charger is broken and over charged the battery.
If the bike is running, why do you need to put batteries on a charger? The only reason for that is a battery is going bad.

If your bike was running and you do not use a charger and you get 18v, then your voltage regulator is bad and you need to replace that.

Old fashioned lead acid batteries probably can survive the over voltage.

[amkluttz]

I'm glad you posted this.  I did have a bad regulator/rectifier and replaced with one of the FH012 MosFet models.  Afterwards I was reading 18+ volts.  I didn't even think about the battery in the multimeter being bad.  I'll check it out, thanks!

-Andy