Mike Schumann wrote:
I find it difficult to believe that adding a battery would cost $1,000. I
would think that this could be included as part of the installation of the
transponder.

FWIW, we had a great deal of trouble with battery failures using a Terra
TRT250D transponder (nearly twice the power consumption of a Becker,
which wasn't then available in the US) in our Duo with the standard
installation of two 7ah batteries. We would get about 3 to 4 hours out
of each, failing to switch at the proper time would result in a useless
battery after a few cycles. We wanted to switch to 12ah batteries, but
there is essentially no room in a Duo for anything that size in an
accessible spot, if we still wanted to continue to carry drinking water,
survival kits, and/or jackets (this isn't the only glider with this
problem). So, we had the local shop reshape the molded battery wells in
the floor to accommodate the larger batteries. This involved cutting
out the existing wells, molding new larger ones, glassing them back in,
and painting. When all was said and done, it cost well over $1000, but
it solved the problem...

Marc