Respond off list, if you think it would be of no interest to the general
list population...

I recently got a second solar panel, a 75w 4.5A 16.6v rated with 21.4v
max...  I was running this during the winter with our old 40w plastic
panel,which had a built in charger/controller.  I do not have any specs on
that, and that is out of reach right now....The two panels kept our two
large deep cycle/marine batteries well charged...the original 40w panel
alone was not up to the task, except with very sparing electric usage and
bright full sunshine every day...

  So, I brought the one newer panel home with us and I would like to get a
proper controller so I can use it to charge the vanagon or any other
'remote' battery I have need of during this summer..

  But I have no idea what any of the numbers mean on the charge controllers
I am looking at, when it comes to selecting the proper one...Here's the
numbers I am thinking of from the Northern Tool company...

3.5 amp- 52.5 watts....$20
8.5 amp-  127.5 watts. $29
10amp.   150 watts       $59
30amp 450 watts           $99

  I am guessing the second one would work.  Cost is a factor for me, too.
I will be using this on various starting batteries, mostly.  If need be, I
will take the controller out of the circuit again when I go back to the
desert and hook it up in series with the second panel and the controller
that worked fine for us this spring and winter....

  In order to charge a big fat RV deep cycle battery, do I need a big
expensive charger/controller?   What do these numbers all mean?  Anyone
want to give me a quick bit of advice on this?

  I just stuck the panel in the sun and I get 21.x volts out of the
wires....a plug on a 8 gauge extension cord a few feet long.   I am
planning on keeping a plug, after the controller, and ending it in a couple
of jumper clamps for use around the ranch and campsites...
  Thanks...Don Hanson