Mystery current drain (Gen 2 B12)?

[WabashMX5]

My '03 B-12 has 5K on it; I've had it for a year (bought it with 1.7K on it).  The battery was dead at the beginning of this season and wouldn't hold a charge, so I replaced it.  It was fine for a month or two, but no longer.  After a week (maybe week and a half) of not being ridden, it needed a jumpstart this afternoon.

Even then, the bike died for lack of electrical power at the first stoplight I came to.  Long story short, I had to fast-idle it at about 2500 RPM for it to even make enough current to keep itself running and make it a half-mile home.

I'm charging it overnight so that I can use the Electromotive charging-system flowchart in Stormi's sig, but was hoping for a shortcut.  Do the G2 B12s have a particular electrical Achilles' heel that I should use as a starting point?  With these symptoms and with my riding habits, I could just have a parasitic current drain — or it could just be a charging problem that the new battery was able to mask until now.

Any pointers, or shall I just chase it down with the Electromotive procedures?  Thanks in advance for any help....

[Red01]

Generally speaking, the B12 charging system is pretty good with the 2G being even better than the 1G.

It may be possible your new battery didn't get a full initial charge, but after you charge it up, that should answer that question. If the battery checks out good, I'd look for shorts or loose connections in the charging circuit.

[WabashMX5]

Well, it's been on a trickle-charger for the past 24 hours, and the battery is shot.  (The multitester shows 12V across the terminals with the bike off, but ZERO with the bike on; once it's under load, it falls flat on its face -- the gauges don't light up, nothing.)

All I can figure is that I blew it when I replaced the battery earlier this year.  It came with the wrong instructions, so I didn't know that I was supposed to add BOTH vials of acid.  Instead, I poured in just one of them, charged it overnight, and had a 6V battery the next day.  Then I added the other vial of acid and charged it, and all seemed to be well.

Would that have done permanent chemical damage to the battery to reduce its lifespan to just a couple months?  Or might my dead-as-a-doornail battery just indicate some other, deeper problem?

[WabashMX5]

...and a second, related question.  I'm still concerned about the bike dying at a stoplight -- I thought once it was started, it would generate enough current to keep itself running, even at idle speed.

Am I wrong?  Is it normal for the bike not to charge at idle?  Or is that a problem in itself?

[H2RICK]

Am I wrong? Is it normal for the bike not to charge at idle? Or is that a problem in itself?

Most bikes (Bandits included) will NOT start charging until about 2000+ RPM. It's the nature of the beast. I believe there's a graph with alternator voltage output versus rpm somewhere in one of my SACS engine manuals that shows this but it may take me a month of Sundays to find it.
I'm sure a competent electrical engineer (which I'm not) could explain why this is so. I have a fuzzy idea of why it works this way but I don't want to embarrass myself in front of the world.....

[WabashMX5]

Most bikes (Bandits included) will NOT start charging until about 2000+ RPM. It's the nature of the beast.

Thanks!  That's a relief, and it explains a heckuva lot (including why I hadn't noticed any problems until now, since when I ride, it's typically for an hour or two with little to no idling).

But now the question is why the battery didn't STAY charged with that kind of riding.  Does my chemical-damage theory (see above about the acid snafu) make sense?

[pmackie]

But now the question is why the battery didn't STAY charged with that kind of riding. Does my chemical-damage theory (see above about the acid snafu) make sense?

Maybe...or just as likely, you didn't fully charge the battery after filling and before installing. In my experience, you need to fully charge the battery prior to installing (several hours at least). The charging system seems to hold the level fine, but does NOT seem to bring a low battery up to full charge.

Even after keeping a battery tender on my battery all winter, I still have to put it on a full charge every spring to bring it right up, the charge system does not do it.

[WabashMX5]

That's encouraging, too -- though I charged the battery before use using a slow-charger (not just a battery tender) for somewhere between 12-24 hours.  Still, soon as I get home from work, I'll fill the new battery (old one was replaced under warranty) and make sure it sits on the slow-charger for a full day before installation.  We've got some rain in the forecast, so I don't think it'll cost me any ride time....