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.

Here are the classic symptoms of battery failure:

• Gauges on (neutral, oil and temp) but the starter won't catch
• Tach starts bouncing, and then the engine starts to act like it's out of gas.
• Engine keeps coughing, but tach is much higher than it should be, or it is bouncing wildly from low to high.
• Bike surges with turn signal on.

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, see that it shows 12v DC and right away say it's fine. The truth is, if the resting voltage (after sitting, not on a charger) is below 12.2, that battery needs to be replaced. Below 12v and it's dead, for all practical purposes.

To confirm the death, do a little more investigating. 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.