I can't help but feel that the obvious solution is to look at ways of
making removal and refitting the battery in the glider easier. Then take
it home and charge it. As you live so far from the flying ground it would
be a real disappointment to arrive and find that the battery is flat
because something wasn't quite right.

Best wishes

John

At 04:55 17 January 2011, Ed wrote:
Thank you, Eric, this is a good start knowing that I have to upgrade a
bit.

The complicating factor is that the glider is tied down on the flight
line in the summer, far from the trailer. Whatever I come up with has
to be a self-contained, compact and secure solution which will either
fit in the glider or is weatherproof and resistant to wind. Most 20 W
panels make excellent weathervanes, and the only securing mechanism I
have is the tie down cable and eyes. Since I live an hour from the
airport I need a "set it and forget it" solution that charges while
I'm away. I don't often fly on back to back days, and I do get some
recharge from the alternator on launch as well, so I probably need to
make up only about 6-8 Ah.

You've given me an interesting idea. I wonder if I could construct a
small aux battery box with a LN5014 DC/DC converter which I leave in
the glider to top off the battery after I leave. On return to the
airport I could remove the unit and charge it on the AC charger in the
hangar while I'm flying. If that few hours of recharge cycle time were
not enough it would be easy just to buy a second battery and swap them
out so that a fully charged one is always ready when I leave the
airport.

So this leads to two more questions....

Is the LN5014 ok to leave attached for that long (ie., is it like a
charge controller which will shut the current off when the main
battery is recharged)? If so, is it possible to do what you do with
respect to connecting my existing 300 mA solar panel and Morningstar
controller in parallel?