what is your routine when storing van/camper for a while

Peter. How about a 10amp solar panel and reg,permenantely hooked up to a 200ah agm battery in the van when the van is in storage,just to keep it topped up??

Keith,

nope, wouldn't do it.

Just to keep the 200Ah topped up, the float voltage provides a low current through the battery, as low as 10mA/100Ah @ 20 degrees, a power requirement of 272 mW, just a bit over a quarter of a Watt, for a 200Ah battery.

Anything below this, and the battery will sulfate, and anything above and the battery will dry out over the 24 month period.
To complicate matters, the ideal float voltage needs to be temperature compensated.
It's better to have the battery sitting there o/c for a few weeks/months before it receives a proper boost charge. Any sulfate crystals which would have formed in the meantime will get recycled into the electrolyte on boost charging.
This way, a constant overcharge cannot happen, i.e. the battery won't suffer loss of electrolyte and/or excessive positive grid corrosion.

Best regards, Peter

Considering a life time of 8 years under favourable conditions, your battery would depreciate 25% over 2 years.
Therefore, I wouldn't store a battery for 2 years, I'd flog it off instead and buy a new one later.

If you're not comfortable with this idea, you could try the following:
Buy a 240V timer (about 20 bucks at Kmart), and program it to switch on your battery charger for an hour or two.
Make sure it's got an alkaline battery for memory backup (don't let black outs wipe your program settings during the 24 month period).
I'd have the battery and charger free standing on a concrete slab just in case something happens to the setup while left unattended.

One word of caution: some chargers discharge the battery while connected to it and the input power is switched off.
You can find out if your charger is ok, by wiring an amp meter in series and watch out for any reverse current when the input power gets switched off.

Best regards, Peter

I'd have the battery and charger free standing on a concrete slab just in case something happens to the setup while left unattended.

****

There are recommendations about advising NOT to store batteries on concrete!

Yes, I've heard that one!

Although no plausible answers seem to exist, I can think of a reason for this:
in cold winter regions, the cold creeps through the concrete slab into the heated room environment.
It's not uncommon for some basement floorsto reach temperatures just barely above freezing (Siberia, permafrost anyone?).
This, together with the higher room temperature can cause a temperature gradient within the battery.
This in turn can assist electrolyte stratification inside the battery, a non-desirable effect.

But hey, M&M&A live in Australia's NT!

Anyway, for peace of mind, a timber board or similar can be put between the battery and the concrete.


Best regards, Peter