A Speed 600 can pull well over 20 amps with the certain prop/battery combinations. It all depends on what you set up.

You can download Motocalc for a free 30 day trial and play with it to see what the amp draw will be with various batteries, gearbox, motors, esc's, and props.

www.motocalc.com

Motocalc will allow you to test out various senarios without "smoking" components.

You will have to input data from your height above sealevel, airframe, motor, gearbox, battery, prop, and esc. The program then does the work for you. Initially it appears complicated, but after you play with it a little, it gets much easier.

The program is not exact (none of these programs are), but it will get you close and it will save you some components.

Many components are already loaded in the program. What is not loaded in you can add by knowing the information which the program is requesting. Most manufacturers websites have this information available.

Just my 2 cents. Motocalc is free for 30 days. Might as well play with it.