Here ya go:

http://www.sterling-power.com/products-altbatt.htm

They promise:

* Charge your batteries over 5 times faster
* Input an extra 50% extra power into them plus de-sulphate the batteries
* Make them last longer

That there puppy takes the output of your alternator and splits it into
two outputs: the first is designed to charge the starter battery, the
second is a multi-stage deep-cycle charger with equalization stage.

The 80 Amp model is a mere �290.99

Connect it up to your alternator and your deep cycle and up the rpm's a
bit and that thing will suck on the alternator as hard as it can to pump
power into your deep-cycle batteries.

If ANYONE tries this thing, I'd like to hear about it.

--
Mike "Rocket J Squirrel" Elliott
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
Bend, OR
KG6RCR

On 9/5/2009 2:03 AM Malcolm Stebbins wrote:

> I know very little about electricity!  I checked the archives  and I found this article, but it did not exactly answer my question:
> http://gerry.vanagon.com/files/motorhome/Motorhome-Alternator-Charging-Systems.txt
>
> I have 2, 6 volt deep cycle batteries hooked up and I have about 200-ish amps (I think) in the aux batteries.  This is used to run my Waeco fridge, which takes about 7 amps when it runs, but only runs about every 10 minutes for 2 minutes-ish.
>
> Usually I only park for a day or 2 max, so  all is OK with the aux battery, but  this last trip I stayed parked for 4 or 5 days in a row, and the fridge's 'low battery' light came on.
>
>  My question is:  APPROXIMATELY what is the charge rate IN AMPS for a nice good working system.  I say good system as I have a new Zetec engine with a 100+ amp alternator and the wires are all new and the batteries are relatively new.
>
> I use a SUREPOWER 1315 isolator for the 2 battery sets.
>
> When the battery got low, I took to idling the van for about 15 minutes in the morning, and again 15 minutes in the evening, to help the battery a bit and this seemed to help.  Is this folly?
>
> Thanks   Malcolm
>