Do I need a new battery?

[scdavis0]

I left the country for 3 months, and I neglected to disconnect the battery.  Predictably the battery is dead.  I charged it for about 6 hours with jumper cables connected to my car.  It helped a little bit but it's still dead.  I then connected it for about 20 hours straight.  Again it seems to be getting a little better, but it's still dead.  Am I wasting my time with this method?  Do I need a new battery?

[Dan02GS]

I would get a new one, might as well throw in a battery tender if you can. That way if you leave it for days and days it wont go bad. Remember it is a YB10l-B2. That way you get the vent on the right side.
Funny how MC batteries discharge so quickly, maybe it is because of there size, not sure.

[Kerry]

I bet that if you hooked a voltmeter across the "dead" battery's terminals, you would get a reading of 12+ volts.  (Not much in the way of amps apparently....)

If you hooked a voltmeter across the good car battery, you would probably get a very similar reading.

Unfortunately, to charge a battery you have to apply a voltage appreciably higher than the battery's "running" voltage.  That's why the output from your bike (or car) alternator is up around 14+ volts; so it can provide a charging voltage to the battery.

In other words, if you don't have access to a battery charger you would almost have to connect your bike battery (disconnected from the bike) to the car with the car running, and perhaps even running at a pretty good RPM.  Not a very efficient solution.... 

The best thing to do is buy (or borrow) a charger, or take it to someone who can put it on the charger for you. 

[scdavis0]

Kerry,

Do you have any idea how long it would take to charge with the car running?

If I buy a battery charger will anything from the Home Depot work?  Or do I need a special motorcycle battery charger?

[Kerry]

Do you have any idea how long it would take to charge with the car running?

Hmmm ... no, not really.  40 miles worth? 

If I buy a battery charger will anything from the Home Depot work?  Or do I need a special motorcycle battery charger?

Some folks have had good luck with car chargers on the lower amperage setting.  The first thing I ordered when I got my bike was a 1.25Amp [Battery Tender Plus], so I don't have any personal experience with non-MC chargers.  Nowadays, for battery maintenance, I would probably get a .75Amp [Battery Tender Junior] instead.

If you have the luxury of waiting (? ?) MAW seems to have just about the lowest prices ... [HERE].   MC dealerships should have some options, too.

[mikesgs500]

I would just get a new battery.  When I first bought my GS it had problems with the battery dying if it sat for more than a couple of days when the nights were in the 30s.  If i connected the battery tender to it it would start up ok, but sluggishly so at times and I was always worried it would strand me (although you could push start).  I picked up a battery from the local auto parts store for $35 and filled the acid and charged overnight and the bike fires up right away even after leaving the bike sitting in the cold for a week or two at a time.