Sudden dead battery.

deafanddiabetic · Post by **deafanddiabetic** » Thu Mar 17, 2016 11:22 pm

I'm having battery issues and it's a strange one.

My old battery is almost two years old, so for the first time riding the Dream I charged it to 12.85 volts, went for a ride and the bike died with no power of any kind in the middle of driving. Couldn't turn it back on to get any power. I pushed the bike home (several miles...) and fidget ed with the battery, the fuse wasn't blown but after moving some wires around I got power back but the battery was only 10 volts.

So I checked the charging system. When I Rev the bike I can see the voltmeter rising. For example at 10 volts I see it rise up to 12+. I thought the battery might be bad so I charged it overnight and checked it when it was finished, almost 13 volts. I stuck it on the bike and revved it again and watched it to up to like 14.5 volts so I presume my charging system is working fine. Right?

Next, I bought a new battery. Brand new, charged to 12+, sealed and expensive.

Stuck it in the bike, everything is working great. I start riding out of the driveway and poof, all power dies and it will not come on again. No lights, etc.

I take the battery in the garage and test it and found it at 10.85 volts. Whoa! How did it die in less than a minute or two that quickly when I know the charging works!

I could be wrong but I'm hoping someone has an answer. It's this possible that it's my battery posts hitting the side steel cover and shorting out? There's no battery strap, so it could move around I suppose.

Would that cause the symptoms in describing? I figure tomorrow I'll put some rubber on the inside of the cover tomorrow to test this idea.

Any thoughts?

DianneB · Post by **DianneB** » Fri Mar 18, 2016 5:12 am

It sounds like your suspicion is on the money. My '67 Dream shorts to the cover if the battery isn't restrained. No way a battery should drop 2 volts in a matter of minutes.

You may consider a better meter, one that reads to at least 2 decimal places. When you are dealing with electrical systems, you REALLY need two decimals to know what is going on.

deafanddiabetic · Post by **deafanddiabetic** » Fri Mar 18, 2016 9:12 am

I'm glad I was on the right track, it was just so strange. I need to rig up a battery strap, I think.

I also typed this on my phone last night and realize how many bad errors were in there. Glad you could decipher it!

Hamamatsu Nippon · Post by **Hamamatsu Nippon** » Fri Mar 18, 2016 12:56 pm

For now you can tie down the battery with two large cable ties. This works well. If you are charging at 14.5v that is incredibly good for a Dream. Have you replaced the original selenium rectifier with a modern reg/rec? if you lost 2v within minutes with a brand new battery, look for an obvious positive volt drop. I agree with Dianne. Also try running without the cover installed.