Can an atm battery suddenly go bad?

[BeerCan]

My new to me 981 suddenly seems to have a dead battery.
I keep it on a ctek constantly when not in use. Every day I've looked at it its been in the green. Today yellow number 3. So I put my big charger on it and it's taking a solid 10 amps.

Battery is a banner agm from 2016. PO says he kept it on a tender constantly and it had a ctek cable hooked straight to the battery when I picked it up.

 

[Donald]

Well you need to pull the battery, charge it and then get it tested.

 

[CharlieBauer]

AGM's should not be left on float.

 

[BeerCan]

Originally Posted by CharlieBauer
AGM's should not be left on float.

From what I understand this charger is not a true float. I think it monitors the voltage and only turns on when it gets to a certain low point

 

[JHZR2]

Originally Posted by CharlieBauer
AGM's should not be left on float.


Rationale?

AGMs in data centers, cell towers and other UPSs might say otherwise.

 

[Mr_Joe]

I just replaced an OEM battery from a 2017 Honda CR-V. It took me a few looks to believe it actually WAS the battery. I guess that battery is over 3 years, counting lot time & all.

I gained near 100 CCA with the MAXX battery, so far all is well.

This was the soonest I've ever had an original battery go bad.

 

[wag123]

Originally Posted by Mr_Joe
I just replaced an OEM battery from a 2017 Honda CR-V. It took me a few looks to believe it actually WAS the battery. I guess that battery is over 3 years, counting lot time & all.

I gained near 100 CCA with the MAXX battery, so far all is well.

This was the soonest I've ever had an original battery go bad.
Three years is all I have gotten out of the undersized motorcycle battery in my wife's CR-V, even the MAXX.

 

[CharlieBauer]

Originally Posted by JHZR2
Originally Posted by CharlieBauer
AGM's should not be left on float.


Rationale?

AGMs in data centers, cell towers and other UPSs might say otherwise.


Maybe they have more sophisticated charger / maintainers?

I got this info from AC Delco's AGM charging instructions:

"Once fully charged, charging must stop. Do not leave battery on a continuous trickle charger."

https://images-na.ssl-images-amazon.com/images/I/81OnyjN8dKL.pdf

 

[JHZR2]

Originally Posted by CharlieBauer
Originally Posted by JHZR2
Originally Posted by CharlieBauer
AGM's should not be left on float.


Rationale?

AGMs in data centers, cell towers and other UPSs might say otherwise.


Maybe they have more sophisticated charger / maintainers?

I got this info from AC Delco's AGM charging instructions:

"Once fully charged, charging must stop. Do not leave battery on a continuous trickle charger."

https://images-na.ssl-images-amazon.com/images/I/81OnyjN8dKL.pdf


Ok that's true if uncontrolled.

One with appropriate steps and temperature compensated float is fine.

 

[bbhero]

True ^^^^

Though the Thin Plate Pure Lead batteries which are extremely well built and true deep cycle AGMs in that circumstance those batteries self discharge rate is extremely low.... Exceptionally low in fact... Less than 1% charge loss per month left sitting in a controlled temp environment...

Those batteries are much better at low discharge rate than the typical calcium AGMs...