I was using the E-flite 20amp esc. Ive used the BP21 with two different batteries.

A Tanic 7.4V 1550mah Lipo (I use this outdoor where the weight doesnt matter as much...and it lasts a LONG time) With a high throttle, ripping flight in my pattern plane, for about 15-20min non-stop, the battery just gets lukewarm.

and

A Thunderpower 7.4V 730mah Lipo (for indoor flying, because its SUPER light) Indoor flying, slow speed, 7min flights, its just a tad warm...not even lukewarm.

I dont know what the discharge rate is on that Electrifly lipo, but as long as your not running around at full throttle and dont over prop it, you shouldn't have a problem. I think the Tanic is a 10amp discharge, 12amp burst. The Thunderpower is probably about the same.

If you build that shocky light, it should hover between 1/4 to 1/2 throttle on that battery. Bear in mind that a 3cell lipo will put out 21oz of thrust on a BP21. If your entire plane only weighs 7-9oz....what in the world would you need full throttle for? And if you did somehow manage to get that thing up to full throttle, it would probably rip the wings off.

I really dont think you'll have a problem. My suggestion would be to test it before flying it. Its ok for the battery to get a little warm, but if it gets hot to the touch, and starts expanding....look out!

Anyone know what the discharge rate on the electrifly lipo's is? As long as its 9 amps or above, you'll probably be able to get away with it.

I cant imagine you ever even getting that thing to full throttle. My outdoor pattern plane weighs 10.3oz. With the 2cell Tanic, at full throttle, it will clip by at about 40mph, and pull vertical easily at about 3/4 on the BP21. And its BIG...58" wingspan.

The shocky is about 42" wingspan, and only weighs 7-9oz at its worst (5-6oz if built right)....Its gonna be a rocket with a 3cell.