Battery/charging

Wanted to take the bike out for a good test ride last night, make sure it wouldn't strand me on the side of the road... I admit the battery was not completely charged when I hit the road, but I figured it'd be okay as long as it's running. Must be charging, right? Started it in the garage, lights get brighter when I rev the engine. I remember reading that question "do the lights get brighter when you rev", but can't remember what was the good answer and what was the bad.

Pulled in the clutch for a downshift and it died on me. Started it back up and got pulsing lights depending on RPMs. Took it back home, checked the output at 2000rpm: 13.8v. Is this too low? I checked the brushes earlier and they're way above the wear line.

Is it just that I didn't charge it up enough to begin with? I just made an assumption that it'd be okay, since you can jumpstart a car and drive it until it's charged. I'm told by the PO that the battery is new this year. It did sit dead for a while when I was having other problems with the bike and had no charger. Would that kill it?

 

13.8 is a tad low, but still within specs, and certainly enough to be charging the battery.

If the lights are actually pulsing, you could have a problem with the voltage regulator - put a good analog meter on the headlight circuit while it's running and see what it's getting.

Lead-Acid batteries can be damaged by extended periods of deep discharge - so though it might be possible to charge it, it may not hold that charge any longer, or possibly not under load. You can have the battery load tested at any shop that sells batteries usually. Canadian Tire will do it for you too.