I exchanged my Hubsan H501S TX 1300 Mah battery for a 2000 Mah battery. I Velcro'd it to the TX case. This should allow more flights before charging the TX battery.
Sorry Hal, I've got fishing on the brain and not thinking straight. Funny thing is that I did notice that you mentioned that this would "allow more flights before charging the TX battery" I assumed that you were doing 20 second flights hahaha