3 1/2 years ago I bought a Platinum AGM Plus 100Ah battery, 3 year warranty.
It was installed in my 2007 Triton 430 and the charge control was connected via a permanently fitted Ctek MXS 5.0 smart charger.
My caravan lives in a car port adjacent to my garage and is connected to an EHU which is always on thus the battery is permanently in the care of the smart charger.
The only time the battery was not connected to the smart charger is away on a grass only pitch with power supplied via a solar panel, connected directly to the battery via its built in charge controller

I now find I have a duff battery, voltages OK but very little capacity. About 2m on the motor mover and then dead flat.

Unsurprisingly I am disappointed with this situation. I pretty much expected to get a lot longer life out of that quite expensive battery.

I can't determine if it was a battery failure on its own or induced by the constant connection to the Ctek charger, it's supposed to be safe unless it's faulty of course.
I had to buy a new battery (same Platinum) from the nearest caravan place to the campsite I was at. (sadly more expensive than I could get it online)
The new battery has charged up by going through the various stages of the Ctek and I was able to get hitched up and then maneuvered in to position at home.

I'm currently testing the old battery and it has definitely lost the bulk of its capacity. Any ideas how to test the charger or should I ditch it just in case and revert back to my old dumb charger on a time switch.
If I ditch the Ctek I would need a new 12V supply system in the caravan as the old charging unit in the BIP is faulty...........

Thanks Colin.
I think the Ctek is just about the same age as the battery as I bought the Ctek for its AGM charging ability.

Two thoughts arise; I can't diagnose a fault on the Ctek at the moment. I have let the Ctek loose on the new battery and keeping an eye on the voltage. At the moment it is following the proper stages/voltages as it should. So I couldn't go for a warranty claim anyway.
Second observation is that in my wonderweb research I have seen that Ctek will not accept a warranty claim on an item bought on Ebay, that's a whole new can of worms.

I'm on the penultimate stage with the Ctek at the moment. It will hold at 13.6V for a few days before it goes in to the maintenance pulse mode.

Guess I'll have to wait until then to see if it switches the higher voltage back down.

Earlier this summer I bought the latest BMW battery charger, (which does cars and motorbikes and Lithium too), and I believe it is the latest CTEK under the BMW logos? Anyway it is fantastic and it has already restored two seemingly duff batteries that I had kept hold of because I can't throw anything away. It does claim to be able to desulphate poorly batteries. Not sure what relevance this has to your problem, however I have had issues with other dedicated trickle chargers in recent years, one an Optimate (Triumph branded) that just gives up before restoring full charge...

Just a thought, a batteries life starts when its filled with acid/gel etc. It's knowing how old the battery was when you bought it !!

Good point monoboard.

That had occurred to me but the old battery and the new one do not have dates on them.

Car batteries always used to have dates.

With thanks to Ray Lawrence for the original post, I realised I hadn’t checked the van battery for a “ while “ . I have just been out and connected the Ctek charger and apart from the cold, I will leave it until tonight. 5 leds to start with !