Battery reads 12v get one crank then nothing...?

[njcafe84]

I keep my battery on the tender and after a short ride today it read 12.38v. After shutting it off and trying to start it with the electric start I got 1 crank and then nothing. Almost like the battery is completely dead. Could it be the starter solenoid? Anyway to test it? What else should I look into?

 

[xschris]

Are you using a full size battery? 12ah

 

[njcafe84]

Yea...a yuasa one

 

[xschris]

After is the volts very low? If not you could have a bad cell and the battery can't handle a load.

 

[xschris]

12.38 is kind of low after a ride. My 79 reads around 13v after a short ride.

 

[njcafe84]

I was thinking if switching to a maintenance free yuasa battery before riding season guess now is a good time to order one.

Even when the starter wants to crank the bike over it always cranks so slow. Like there isn't enough juice to get it moving fast enough

 

[bcware]

These numbers vary a little depending on battery type.

Charge
100%	12.8V
75%	12.4
50%	12.2
25%	12.0
0%	11.8

"It's easy to be fooled into thinking a battery is fully charged because the voltage has jumped up after a charging source has been on even for a short period of time. And, when the voltage jumps up appliances that were not running (because the voltage was too low) will come to life again. But this positive state generally won't last long and the voltage will drop off again quickly if the batteries arent fully charged. The trick is to check the voltage on a 'rested' battery which has had NO charging or discharging for 6-8 hours"

 

[Lou Ranger]

.... The trick is to check the voltage on a 'rested' battery which has had NO charging or discharging for 6-8 hours"

I can second that.
Last summer, my brand new battery was less than 6 weeks old and it developed a bad cell.
It would read 12-ish immediately after being charged, but would stop short of 14 when being run and revved. I could get almost 14 off the 5 cells when it was being charged.

However after a few hours of sitting unplugged, it would drop down into the low 10s and would not turn the engine over.

 

[njcafe84]

Had the battery off the tender all night. Just checked it and it read 12.4v

Is there any way of testing the starter solenoid?

 

[xschris]

Even if the battery says 12.4 it may not be able to take a load. Most garages can load test a battery for you for free. If you have a jump pack you can try hooking that to the bike as well as your batter and is if spins over well then you know is your battery.

 

[njcafe84]

xschris I jumped it off my car and the motor cranks over when it's connected to my car via jumper cables.

Does this mean time for a new motorcycle battery?

 

[willem]

Get a new battery yes.

I had issues with a brand new one as well, it lasted 2 rides and then died miserably. Yours doesn't seem to be holding charge, so get a new one.

 

[willem]

Yuasa works for me, but I've also heard good things about Motobatt

 

[bcware]

I constantly have problems with traditional batteries. At some point all of mine seem to start boiling over even if they do last a while. I guess you could buy more acid to top it off; distilled water only goes so far before you're just diluting the electrolytes. AGM batteries have been 100% problem-free for me. They're more expensive, but definitely worth it in my opinion.

 

[xschris]

Agree with the agm. But topping up with distilled water don't hurt the battery it's the lead plates inside that go bad from contaminates on them. The battery in my 79 is 8yrs old and still takes a charge. It gets topped up with water 3-4 times a year. I once had a car battery for 12yrs doing the same thing. If the 79 wasn't a factory correct resto I would put a AGM in it. They are far better.