We bought a 530 in autumn last year. Brand new with a 95Ah AGM battery in it. First time we looked at the caravan the battery was dead. The dealer did it is normal because we don't have the caravans connected to the mains. We got the Eriba home and went for a short four day trip. As we were expecting the Swedish winter with snow and low temperatures we put the caravan in winter mode. I took the battery inside the house and put it on my Ctek charger (AGM mode) and let it charge for a week. The voltage was over 13 volts when I disconnected the charger. When I measured the battery after a week the voltage had dropped to 12.87 volts. Is this normal or has the battery been damaged because it was without charging at the dealers? I read that it is not good to leave a AGM battery to drain completly.

Ctek recommend recharging with “Recondition” mode after a deep discharge. I do this a couple of times a year with my boat batteries and they always recover. However I agree with Pepe le Pew, it seems as if your battery is fine.

Capn C

Just beware that a battery that has been allowed to go completely flat for a protracted period is invariably damaged.
It may well be revived with a smart charger that can get the voltage up to an acceptable level. However, what is missing is the capacity of the battery. A 95AH battery may well hold 12.8 Vdc but it may also have lost much of its capacity. It may only hold that charge for a short time and effectively become a 30Ah battery for example.
Voltage is not the only test for a good battery.

As Ray notes, regular batteries do not respond well to a complete discharge. However, I presume your new 530 came with a new leisure battery. These are deep cycle affairs and are designed to allow you to drain them to 50% to 60% on a regular basis. It is not recommended to allow them to drain below this level on a regular basis but most leisure batteries will put up with a deep discharge on an occasional basis. Don’t ditch your battery yet. Test it over a couple of days running, say the fridge, and see if it holds up.
I have given my leisure batteries (2x110Ah and 1x85Ah) some serious abuse and the Ctec charger always brings them back to life.

Capn C

I have an old classic car and I sometimes have a flat battery if I am working on the car for a long time with the battery disconected. I am not sure what CTEC charger you have however the one I have got is not able to bring a flat battery back to life, it's only good for a trickle charge. I have an old car battery charger which gives it a kick in the pants and then I can use my CTEC to keep it topped up.

I also found this trick Poptop320.

The Ctek charger will not fire up if it spots a very low voltage from the dead battery. Give it a blast with an old fashioned "dumb" charger which will raise the voltage sufficiently for the Ctek to take an interest.

To answer the original question I completely agree with Pepé Le Pew that a battery which shows 12.87V a week after charging is in very good condition. Your job is simply to keep it that way by allowing the Ctek to do its job of charging when it is not in use.

Steve.

PS FWIW agm batteries are amongst the best type you can get

Just adding to my post #4 above.
my real world experience is of a battery that was badly discharged due to a heater fan being left on. Charged it up with a standard battery charger and then a CTek for a few days. It held its charge at about 12.8 V for a few days OK.
Off I went for my first trip of the year in April, off grid as usual. Used the motor mover to get stable on a difficult pitch, all OK. Had the LED lights on quite early in the evening, no problem. Thought I would watch a bit of TV before bed using a 230 Vac invertor.......low voltage alarm from invertor. There was no capacity left in the battery. I normally run for 3 or 4 days without a solar charger in the spring/autumn.
Battery no good.

Thanks to all of you