How to tell if your battery is dead

The following is important information for the DIY rider. Quite often a seemingly impenetrable electrical problem can be traced to a battery that is no longer serviceable. This should be the first thing you look at.

Sometimes a battery just dies. Not necessarily from neglect, age, or use. It just dies. This normally comes from sulfates building up along the bottom and shorting out a couple of the lead plates. It's difficult for many people to trouble-shoot because they'll just toss a voltmeter on the battery and see that it shows 12v DC and right away say it's fine. Here's a bad battery (this one died WHILE the bike was running!). It's being tested with a multimeter to find the voltage drop.

Fresh off the battery tender. 13v is good.

Ignition on. 12v. Only a slight drop.

...and starter thumbed. This is the "drop" part of the equation. You shouldn't see lower than about 10v DC:

6 volts isn't good. Time to head to the battery store.