2012 possible charging issue

Water Bear

Joined
May 20, 2025
Messages
1
Age
59
Location
Westmont
Bike
2012 ST 1300
Hello. I just bought a 2012 st 1300 with 4900miles. I left the lights on for 10 mins tops and wouldn't start. Put meter on battery after jumping and atarting and 8dle was showing 12.6v .Higher rpms showed 13.5 - 13.9v. Is this normal? Can old battery cause this if not normal or charging system issue? Thank you!
 
Most likely it is the battery. How long has it been sitting, not running over the last 13 years? Idle lead acid batteries plates will develop a layer of sulfate that will require a bunch of hard charge and discharge cycles to burn off. It is best to just get a new battery. My 2012 has been sitting for 8 years and the first thing I will do is replacing the battery.
 
I put a new battery in mine today. Voltmeter reading was 13.9 at idle 14.2 at 5,000 RPM. A defective battery will give erroneous readings. Fully charge the battery with a proper battery charger and do the check again.

P.S. / F.Y.I. You mispelled Westmount.
 
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As lead acid battery ages, the lead sulfate crystals that form on the plates will undergo a transformation to a harder coating that the anti sulfation cycle of a smart charger cannot break down. This happens to every lead acid battery - flooded and agm. I've read that an auto or mc's charging system will not top off a battery (restore the charge to 100%) after using the car or bike, and the sulfation is inevitable and reduces the capacity of the battery. This is one reason why batteries last on average, 4 to 6 years.

I've read that were one to fully charge a battery after every use, it would last much much longer. Through dumb luck I got into the habit of clipping a smart charger onto my lawn tractor's flooded battery after every use. I'm on my second battery for his machine, the first lasted 11 years, and the second is still going strong after another 11 years. I'm not suggesting anyone slap a charger on their car or bike after every use, and I don't believe in anecdotal evidence. However, I think I've accidentally proven what I've read thatt fully charging a battery will extend its life. That first battery came with the Craftsman tractor, the second was just what was available when I needed a replacement - not sought out for good reputation or long life.
 
Agree w SMSW - have always kept mine on tenders. Tractor, mower, MCs, and vehicles when dormant - last a long time and strong starting.
 
Water Bear said:
I left the lights on for 10 mins tops and wouldn't start. Put meter on battery after jumping and atarting and 8dle was showing 12.6v .Higher rpms showed 13.5 - 13.9v. Is this normal? Can old battery cause this if not normal or charging system issue? Thank you!
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That's a little low. I'd expect to see 14V+ at higher rpm. It could be because the battery is old. A better check would be to watch the voltage during startup after proper charging of the battery. A jump then starting then measuring is not necessarily conclusive.

But I wouldn't be surprised to see that happen with a brand new battery under those exact same circumstances. The ST1300's battery is underwhelming. ST1100s had a higher capacity battery.

I was adding two small LED lights/reflector to my 2010 and the battery wouldn't start the bike after maybe 10min of on time. I bump started it no problem. A 20min ride to work and it fired right up 12hrs later. I've still got that same battery and the bike still fires right up. I keep it on a Tender Jr now. But riding/starting/stopping/starting/riding/stopping the battery doesn't stumble.

I have a jump starter with me because I might leave the lights on. I did on one occasion while my buddies and I had lunch — maybe 90min. The lights weren't on when I came back. My buddy jumped the bike from his RT and off we went. Same battery still in the bike. When acts up under normal circumstances I'll consider replacing it.

If you haven't done so swapping your factory headlight bulbs for LEDs could leave a few extra amps in the battery with the IGN and the engine off.
 
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