Bonneville America Forums Forums Technical Forums General Tech Dead key

I turned the key and heard a click almost immediately and the lights went out. All of them. I had just gone 6 miles and it ran fine. It sat for about 4 minutes before I went to try and move it and zap. I tested battery voltage and it reads 12.7 but drops to zero when I turn the key on. The battery is 6 months old. I first though fuse but why would a fuse cause the battery to drop to zero at the posts. Posts are tight and clean. I checked the connections under the seat and everything seems tight and normal. I would think that with the battery going to zero at the terminals with the key on something would be getting hot but haven't been able to locate it. HELP?

Thanks, Dan

sounds to me like a bad cell in the battery has killed it. I know from experience...I went through a couple batteries in a few month period that ended up like this. check your amp draw when the bike is not running...there shouldnt be any. If there is, you have to find the problem. If not, buy a new battery and ride away.

Dan - BEFORE YOU RUN OUT AND GET A BATTERY - CHECK YOUR FUSES - DO NOT CHECK VISUALLY BUT WITH A METER. IN PARTICULAR, CHECK THE 25 AMP FUSE FOR THE HEADLIGHT CIRCUIT. I say this because you mention the lights going out. I played for 4 days trying to find out why all I had was a click. The fuse did not visually appear to be blown. It was and prevented the starter from energizing (some kind of 'feature'. You also mention the drain/voltage drop on the battery, so it could be something entirely different. Just the same, check the fuses before you panic and spend a bunch of money.

A bad fuse won't case the battery to show no voltage across the terminals, I think it is most likely a bad battery. Even a battery showing 12.7V should be enough to crank it at least some not go to zero volts when you try and start it. And for it to happen so suddenly I would imagine you have a shorted cell. That is as long as I understood you correctly, you measured voltage with the probes on the battery terminals themselves,correct?

Thanks for the help all. I will test the fuses tomorrow. I thought about a bad cell. The wierd thing is that it won't even click with the key turned to the on position. The indicator lights don't even flicker on momentarily and then fade. The voltage just falls to zero within 2-3 seconds. I have had batteries in a truck that would act dead (cell) when you hit the starter but would run low draw stuff like the dome light or radio until you tried to start it. I also realize that everything is different. Luckily I saved the old battery when I replaced it and have it on the trickle charger. (I don't throw anything away as my wife constantly reminds me. ) It was working fine but I replaced it because I didn't want to trust a 4 & 1/2 year old battery on a long ride. The charging system has been working fine as the lights have been bright but then again, I never had a reason to put a meter on it to really see what it was putting out. I will post an update tomorrow as I had to leave it at school. Thanks again, Dan

Just had similiar symptoms, 12.5 no-load volts, then nothing as the key was turned on. Battery tester said "bad cell"- a new battery fixed it
G

Well, I checked the fuses this morning and they all tested good. So I took the old battery off the charger and viola, it started right up. That's what I get for ordering a battery mail order. I should have just went to my local NAPA store and had them order one for me. Thanks for all the help. I am back on two wheels.

Dan

Quote:

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A bad fuse won't case the battery to show no voltage across the terminals,

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I don't recall saying it would...

I didn't say that you did, but he said he measured his voltage at the terminals and when he tried to start the bike it went to zero.

Well, nothing is simple for me. The charging system isn't charging. The voltage at the battery is below 12 with the engine running. Now the question is did that help kill the battery? I will check the alternator and regulator/rectifier tomorrow morning and see if that tells me anything.

That will definately kill your battery.

What I should have said was if you have a good battery and use it in a bike with a bad charging system it will drain the battery.

Yes, I did try and charge the battery (newer one) but it showed a bad cell under a load test. The original battery came back enough (after charging) to get the bike started but the bike showed no charging while running. I wasn't able to check the alternator output at the plug under the carbs today. If the alternator is good, will it show 13+ volts (while running of course) when unplugged from the regulator or does it have to get energized from the regulator/rectifier somehow?

Dan

I guess what I was getting at was; did the weak/dead charging system kill the cell in the battery or did the dying battery overwork the charging system to the point of failure? Kind of a chicken or the egg question, not that it really matters at this point. Both problems have to be fixed.

Dan

The alternator will show alternating current, I don't know the output off the top of my head. I also don't know if ours need to be energized or not , the old ones didn't on the 60s and 70s bikes. My guess is ours don't but that's all it is...a guess.

As I already suggested in a private email to DanB, get one of these batts: http://www.odysseybatteries.com/

I unplugged the regulator/rectifier harness today and tested the alternator side. I got 9.7 volts from one cavity and 3.8 from another. The others were either dead or showed negative voltage.