Strange battery problem. Any explanations?

[david223]

I don't understand what happened here, hoping someone can explain it...

Just before going for a ride, I noticed the left bolt on the front of the gas tank was missing. So I start her up, ride to the dealership to order a new one, then go for an hour ride, get home and park in my garage.

Eight days later, I'm set for a full day ride that had been planned for a couple of months, all geared up and packed. I get on the bike, and it barely turns over! Now this is a new battery I installed in May, but it's a cheapy and I figure okay, it's been sitting over a week, maybe that's all. I put on the charger and after 30 minutes or so, it says it's charged. I try to start it, hardly turns over again.

I raise the tank to check the connections, and guess what I find? The missing bolt from the tank had fallen onto the battery, with the washer bridging the negative terminal to the frame of the bike. I remove the bolt and set the charger again. This time it takes a few hours to reach a full charge, and when I try it, it starts fine.

The next day, dead again. I charge it again, take the bike out for a 45 min ride, keeping the rpms high just for that extra boost. Next morning, no go again. So the battery takes a charge, but won't hold it overnight.

My question is how can a short from the negative terminal to the frame drain and then kill my battery? I can understand a short from the positive, but the negative?

The obvious solution is to get another battery, but I just want to understand what happened!!

And to top it off, I can't find the receipt from when I bought the battery!

 

[Mattberkshire]

Sorry dude haven't a clue but I'm glad someone else didn't tighten their tank bolts enough. I've got one lost in the guts of the bike somewhere. And a battery terminal connector, using an old nut and bolt at the moment! :thumbup:

 

[Fred]

My question is how can a short from the negative terminal to the frame drain and then kill my battery? I can understand a short from the positive, but the negative?

It can't, since the battery negative is connected to the frame already. It doesn't even qualify as a short circuit.

Had the bolt fallen on the positive terminal, things would have been different. And by "different", I mean "motorcycle on fire."

IMHO, the battery just happened to go bad at the same time that you noticed the bolt problem.

Fred

 

[david223]

It can't, since the battery negative is connected to the frame already. It doesn't even qualify as a short circuit.

Had the bolt fallen on the positive terminal, things would have been different. And by "different", I mean "motorcycle on fire."

IMHO, the battery just happened to go bad at the same time that you noticed the bolt problem.

Fred

That's exactly what I thought, but the coincidence was just too much! And the fact that it wouldn't charge until I removed the bolt, so there had to have been something happening...

There's something else I just remembered. I have the battery tender leads on the battery, and after the first time I charged it (when it didn't actually charge, but the tender went through its cycle and then said it was charged) and after removing the bolt, when I hooked up the tender again, it gave a reading of an improperly connected battery (flashing red light). That's when I noticed that the fuse on the battery tender leads was fried. So something happened to blow that fuse between the first attempt at charging and the second, the only difference being the removal of the bolt... The tender worked fine after I changed the fuse.

 

[bd43]

When you said the battery tender wires were fried, did you install permanent battery tender leads off the battery in the bike? If so, were those the leads that fried, and if so, did you have an inline fuse on that lead installed as close to the battery as possible? The reason for have the fuse as close to the battery is if there is a short somewhere after the fuse, the fuse will blow before cooking wires. Since you cooked wires, I am wondering what size of fuse was actually in there. You shouldn't need more than a 1 or 2 amp fuse, otherwise I'm thinking the battery tender wires were hooked up backwards as in the positive went to the negative and vise versa...

BTW, reversed polarity charging will make short life of a battery.

 

[david223]

When you said the battery tender wires were fried, did you install permanent battery tender leads off the battery in the bike? If so, were those the leads that fried, and if so, did you have an inline fuse on that lead installed as close to the battery as possible? The reason for have the fuse as close to the battery is if there is a short somewhere after the fuse, the fuse will blow before cooking wires. Since you cooked wires, I am wondering what size of fuse was actually in there. You shouldn't need more than a 1 or 2 amp fuse, otherwise I'm thinking the battery tender wires were hooked up backwards as in the positive went to the negative and vise versa...

BTW, reversed polarity charging will make short life of a battery.

It's not the wires that fried, it's the inline fuse, which is actually a 7.5 A. No reversed polarities here...

 

[wolfc70]

It sounds like you either have a bad battery or your tender is dying. I have never had much luck buying cheap motorcycle batteries. I seem to get a year or two max on the el cheapo brands.

It is possible that your tender is bad. If something shorted out inside (moisture?, dropped?) and it is sending the wrong current/voltage to the battery, the battery life will be very short. I have only heard of one case of a tender killing a battery, so it is rare, but not worth overlooking. I would place my bets on the battery.