[coolwhip]

Also see my 9-29-2020 post above.
After my original battery (Duracell) failed after 23 months due to low CCA, I replaced it in 8/2020 with a NAPA battery, and all was well until yesterday. 
Battery tender was on it.  It had 14 volts when tested w/o the tender connected.  It couldn't turn the starter.  I checked all the connections and ground wires I could find; all were tight.  I had the battery bench tested and it only had 125 Cold Cranking Amps, instead of 500.  It was replaced under warranty.
To me, this early loss of amperage (CCA) in relatively new batteries has only happened to this Vanderhall and two motorcycles.  In autos they seem to degrade slowly over time.  I am wondering why.  Maybe the batteries cant hold up to the rough ride.  Is there a better option?

An update to this story:  Original battery failed after 23 months - August 2020.  Second battery failed after 10 months - June 2021.  Third battery failed after 1 year - June 2022.  Forth battery failed after 5 months - Nov 2022.  On the fifth one now.  Some replacements were under warranty, some not.  All failures are the same: retains plenty of voltage (12.4+), but amperage degrades to the point it doesn't have the strength to turn the engine over.  All replacements are NAPA Legends; supposed to be good batteries.  I also recently replaced the tender/maintainer. I have had several long discussions with the manufacturer, East Penn Manufacturing, and NAPA, and the Battery Tender (Brand) "experts".  I am a lot smarter now, but still don't know why the failures.  I'll post again if something changes.  
Does anyone else have similar problem?

[microfox]

Also see my 9-29-2020 post above.
After my original battery (Duracell) failed after 23 months due to low CCA, I replaced it in 8/2020 with a NAPA battery, and all was well until yesterday. 
Battery tender was on it.  It had 14 volts when tested w/o the tender connected.  It couldn't turn the starter.  I checked all the connections and ground wires I could find; all were tight.  I had the battery bench tested and it only had 125 Cold Cranking Amps, instead of 500.  It was replaced under warranty.
To me, this early loss of amperage (CCA) in relatively new batteries has only happened to this Vanderhall and two motorcycles.  In autos they seem to degrade slowly over time.  I am wondering why.  Maybe the batteries cant hold up to the rough ride.  Is there a better option?

An update to this story:  Original battery failed after 23 months - August 2020.  Second battery failed after 10 months - June 2021.  Third battery failed after 1 year - June 2022.  Forth battery failed after 5 months - Nov 2022.  On the fifth one now.  Some replacements were under warranty, some not.  All failures are the same: retains plenty of voltage (12.4+), but amperage degrades to the point it doesn't have the strength to turn the engine over.  All replacements are NAPA Legends; supposed to be good batteries.  I also recently replaced the tender/maintainer. I have had several long discussions with the manufacturer, East Penn Manufacturing, and NAPA, and the Battery Tender (Brand) "experts".  I am a lot smarter now, but still don't know why the failures.  I'll post again if something changes.  
Does anyone else have similar problem?

Coolwhip, have you checked out a Lithium (LiFePo4) battery?
Nowadays they have these types of batteries in the same typical format
of a car battery, designed to be used in 12V cars. They are half the weight,
supposedly twice the power and has a low rate of discharge (when nothing
is draining them). They are more expensive, but are much better in many
ways. Worth an investigation.

Another option, also expensive, is the OPTIMA brand of AGM type of battery.

As for the battery not holding up to a rough ride, perhaps using a rubber mat
under it might not shake as much? Wild guess here.

~

[RustyTeeth]

    I have seen bad batteries like you have described.  Every type battery.  Have 6 Schumacher 28$ trickle maintainer.  Sold at ace, Walmart, goes to float after slow charge. Been few years and a 2013 scooter battery. Still fine. 
The other chargers cooked a fine mist of water out.

I pull batteries and have them on a charge bench.