-> If you have experience with a better system, let's hear it. I'm not
-> saying mine is the only way to do it, just that iot works for me. If
-> it doesn't fit the theory, change the theory ....     ;-)
I've been doing just about the same thing for several months now, and
where I live batteries boil dry REAL easy.
I'm hitting a group 27 car battery with about 800 ma for about 45
minutes a day.  (Actually at night when it's somewhat cooler. 98F
today.)
The car starts crisply even after two weeks without running, and so far
I haven't added any water. (Since about Dec-Jan.)  I've neverr had a
heck of a lot of luck keeping motorcycle batteries up no matter HOW
gently you charge them.....  But, take my 6 volt tractor!  You can whack
that sucker with 2 amps for half a day and it won't boil dry! 
 ^..^
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