I am certainly no authority when it comes to DC electrics and chargers
and solar but I've been around lots of RVers who are and are always willing
to give me advice.   The general gist of the advice is to charge a deep
cycle battery you need a lot of amps going in...and Smart Chargers (so
called) aren't usually great for that...

   I have a smart charger that won't work in our travel trailer's electrics
(two deep cycle batteries)....Neither will the panel charger that is
onboard that older trailer...doesn't supply enough amps(?)...but when you
hook up a vehicle's alternator to the batteries, they charge right up...Or,
if I hook up my old manual battery charger (Schumacher) to the  trailer's
generator and put that to the batteries, they charge right up...My brand
new smart charger....won;t do it....
  the new solar panel I just bought cheap charges the batteries in about
half a sunny day from 11v back to full charge...
  Someone will know the numbers and tell you what you need...but you need
lots of amps like an alternator puts out to 'bust through' into your deep
cycle battery and get it to charge.

On Thu, Aug 1, 2013 at 6:27 PM, neil n <musomuso@gmail.com> wrote:

> Thanks for that Karl.
>
> Recently, I mistakenly drained this new 100 Ah battery down to 11.xx
> Volts then used this 7 Amp charger to bring it back up. The charger
> showed it as charged and didn't display a fault but I should try
> depleting the battery a little then charging it with my older
> "intelligent" higher Amp charger.
>
> Neil.
>
> On Thu, Aug 1, 2013 at 6:09 PM, Karl <tdiguru@westyventures.com> wrote:
>
> > A 7- or 8-amp charger will never bring a battery that's been drained
> > significantly back up at a proper rate. This can lead to sulfation on
> > the plates, shortening the lifespan and/or storage capacity. If the
> > battery is never drained down by more than 10%, perhaps the small
> > charger can keep it topped up. I'm running 40A on a 200ah battery bank
> > that so far has never been below 70% capacity.
>
> --
> Neil n
>
> Blog: tubaneil.blogspot.ca
>
> '88 Westy http://tinyurl.com/c8rlw6p
>
> '81 VanaJetta 2.0 "Jaco"  http://tubaneil.googlepages.com/
>
> Vanagon VAG Gas inline-VR Engine Swap Group:
>
> http://tinyurl.com/d7gd5ej
>