AGM Battery

[apaiva]

great. I just placed an order.

[rev_mook]

I just ordered one too!

[apaiva]

so I bought one of these, received it two weeks ago, charged it, and then installed it and it worked just fine.  I'm in nyc so a lot of the riding I do is very stop and go ie won't charge the battery.
It's very inconvenient for me to put the battery on a tender since the bike lives on the street.  On friday I rode home from uptown manhattan and hit A LOT of traffic so it was lot of sitting and idling and 5 mph cutting lanes.  Saturday morning I rode to a cafe 2 miles aay and it started fine, then riding home I could tell the battery was a little low but it still started.  I let a friend ride the bike, he stalled, and when trying to restart it wouldn't turn over the battery was too dead.  I couldn't even get it to bump start, and the indicator lights weren't lighting I guess because the battery was so dead.  After letting it sit about 10 minutes I tried again and the indicator lights came on and then we were able to bump start and I got home.  I charged the battery with it in the bike and let it charge several hours.  It charged up to 62% pretty quickly (read out on the charger) but then never went above that.  The bike started right up after charging.

Does this seem like an issue?  Did I damage the battery by draining it? Or am I overthinking things? I'm going to be going on a 3 hour away ride this weekend and don't want to get stranded anywhere.

thanks,

[Bob_Roller]

You need to fully charge the battery after the discharge 'event' you had .

Probably more like 12-15 hours, the AGM batteries can take a pretty high charge rate initially .

I just did a pretty good discharge on my battery Sunday, when my (suspect) rotor failed .

Had it on a regular auto battery charger for 7 hours, the initial charge rate was 7 amps after 2 hours went to 2-3 amps .

Finished  the charging with the battery tender about 14 hours total charging time .

[Barry]

I charged the battery with it in the bike and let it charge several hours

Sounds like the battery was really flat. It's an 18 AH battery so you need to put 18AH back in plus at least 10% in which case it will need approx. 10 hours at 2 amps to reach full charge. That could easily be more than your several hours charge and 3 hours riding. You have to be sure it's fully charged at the start and it won't have been when you bought it. Ideally should have been given a charge before installation.

A full discharge won't have done it any good but as long as it's not fully discharged too often it should still last for some time yet.

Do you know what your charging system is putting out above 3000 rpm ? Anything less than 14 volts is going to be an issue with stop go riding. I'd be thinking about a high set point voltage regulator. A regulator set at 14.4 volts would certainly help. Check out the battery manufacturers specifications to see what the ideal charge voltage is.  

[Bob_Roller]

About 5 discharge events like you had, will start to lessen the service life of the battery noticeably .

Motorcycle batteries don't seem to be able to take a lot of abuse, no matter what type you have .