RE: Slow stick batteries
If you have a 300 powered Slow Stick and want 20 minute flights, KAN 8.4V 1050 mah nimhs will do the trick. I flew with 650's before, and am loving the longer flights.
The only thing I wonder about is how much more damage a heavier pack does to a plane in a crash.
I have two park fliers. My BLT is lighter than my slowstick and I have yet to replace a prop or a propshaft on it. I have crashed the BLT, boinked the nose into the ground the same number of times as the Slow Stick, using the same batteries and similar motor and gearboxes. I think the lightness of the BLT contributes to it fairing better in a crash.
I charge my packs with a Great Planes Electifly AC Park Flyer Peak Charger. You set it (200-800mah, I think--I always use 200), plug the batteries in, and forget it. When the cycle is done, they trickle charge between 10 to 20 mah). I condition my nimh packs with the charger that came with my TX. (Size of the battery in mah x 1.4)/80 mah. 80 mah is what my Tx charger will put out for 8.4V batteries. If I've been taught correctly here, you look at your charger for the TX and see what it charges the Tx packs at. Multiply that number by 9.6 (the volts of the Tx battery) then divide that number by the voltage of your pack. That is the current that the charger will put out for your pack.
Happy shopping!