spitfiremk.16

My Feedback: (7)

I have a Stevens Aeromodels Dystraction with a 9 by 6 slow flyer prop, a Castle Creations Phoenix 10 speed control, and a very old 2 cell 700 mah kokam li-poly battery. This is not one of the super high discharge batteries. However, I have never used this battery but i always charged it eery 2 to 3 months to keep the voltage up. It appears to be in good shape. The plane flew great but the motor would cut off on me after about 5 minutes. I charged the battery and it only put half the capacity into it. Do i need to try another prop size? i think that i might be drawing to many amps from this battery. Or is the battery just bad? if anyone could give me any advice or even just give me their opinion on this then that would be great.

Matt Kirsch

My Feedback: (21)

You're spot-on with your first guess. That motor/prop combo is drawing sliiiiiiiiightly too many Amps for the battery's taste. If you were way over the limit, the motor would quit in a few seconds. The low-voltage cutoff mechanism in the ESC is kicking in.

There are two ways to go: Run a smaller prop, like an 8x6 or a 9x3.8. Get yourself a more modern battery with a higher discharge capability.

Frankly, you'd probably be better off with a more modern battery pack. Reducing prop size will also reduce the performance of the plane. The pack you have right now is probably only rated for a 5C discharge at best, about 3.5 Amps. I'd estimate you're drawing around 5 presently, just shooting from the hip. A modern pack this size is only going to cost you around $20-$25... Well worth it, especially considering that performance will be even better because the pack's voltage won't drop so drastically under load.