I'm riding 2014 Dyna Street Bob. Everything is stock condition, nothing much added. My genuine Harley Davidson AGM battery is just over two years old.
I used a voltmeter to test the battery:
It is 12.5v when the bike is off
It is 12.2v when the light is on
It does not able to crank start

I used the CTEK MXS5.0 to charge it over night
I removed the charger and wait for one hour to test it again:
It is 13v when the bike is off
It is 12.6v when the light is on
It is 14.2v around 2000rpm

But it does not hold charge for ~12hrs and the cycle repeat again. I tried the "Recond" function from the CTEK MXS5.0 but it still don't hold charge more than ~12hrs

During these two years, there were two to three times I forgot to turn off the emergency light for about 20minutes and the battery not able to crank start. And there were two to three times I didn't ride the bike for two weeks, it didn't put on charger and it can't crank start. The past few months, the battery holding charge from around one week to three days to two days and this week around 12hrs. Is there anything else that I can test before replace the battery. It is a pity that the battery is just over two years. The bike had the alarm and ABS install from Harley Davidson when it is bought.

Can I say that the two to three times I forgot to turn off the emergency light for about 20minutes and the battery not able to crank start and the two to three times I didn't ride the bike for two weeks, it didn't put on charger and it can't crank start, is it the issue cause the battery to degraded and not able to use more than two years. And is it that it is better to charge one every few days if not riding for weeks because it is the alarm that draw the battery.

I’m from Singapore and the weather is hot 26~32 degrees celsius throughout the year. The genuine Harley Davidson battery is ~$225USD

 

Sounds like the battery is bad. Sometimes they don’t last very long, especially if they go dead a few times.

Get a new battery, and keep it on a battery Tender when you are not riding.

 

Sounds like something is draining your battery and your volt meter is off... Where are you measuring the voltage. Hopefully at the battery and the terminals are tight.

Add:

Also your battery could be draining internally.. Charge it disconnected, and let sit for 2 days. Voltage should be above 12.5.

 

go buy another battery.

 

I’m from Singapore and the genuine Harley Davidson battery is ~$225USD

 

Can I say that the regulator rectifier has no problem because after charging for minimum of 15minute,
It is 13v when the bike is off
It is 12.6v when the light is on
It is 14.2v around 2000rpm

It just doesn’t hold charge up to 6hrs

 

Disconnect the battery after charging and let sit. What is the battery voltage after 24 hours?

 

Fully charge the battery and take it to a shop that can load test it.. If it fails get an interstate battery. They are cheaper than OEM and will last a long time....

 

Buy a battery online and have it shipped to you, I pay about $110 U.S. at Batterymart.com for ones for my Electra Glide Limited

 

a" genuine harley davidson battery" isn't necessary. the bike doesn't know what the label on the battery says. any brand battery that is the right size and amps will work in the bike. the last battery i bought doesn't say "harley davidson" on the side of it and it's going on 9 years old.