Need Help Choosing a Battery....

Mike

Mike

=)
Admin
Any 3 or 4 cell (3s/4s) lipo battery will be fine. As far as the capacity goes, that's where you're going to get into the weight vs. capacity dilemma. 3300 mAh is typically a safe bet for almost any application though.
 
Mike

Mike

=)
Admin
The only problem is that if the prop breaks while you're in the air - it's going to cost a lot more. You should be fine though. Just always inspect your props prior to flying to make sure there aren't any signs that they may break. Your setup should be good based on what you've listed here.
 
G

gregoreo

Member
Thank you so much! Sorry if I am burdening you with my questions, but, I would also like to know how long my copter arms for each motor should be (I am building my own chassis and I don't really know if 10"-12" in length for each arm is appropriate) .
 
Mike

Mike

=)
Admin
Don't worry about it! That's what the forum is for! When it comes to arm length, it's not necessarily the actual length of the arm that matters. Sometimes you'll have longer arms and sometimes you'll have a bigger body (center plate) and shorter arms. Typically, sizes of quads are based on the length, in millimeters, from motor to opposite motor. When you start looking at H frames and other designs, the measurements are a bit different. With 1,000kV motors, 3S battery, and 10 inch props, I'm thinking that a 450 sized frame up to a very light 550 frame would be appropriate. Technically, when it comes down to it, you're going to be most concerned with "all up weight", which is the weight of the copter with all components (including battery) that will be flown. If your power system has enough thrust to lift your copter, your main concern with frame size / arm length would be whether or not the props have the clearance to spin without hitting each other or anything else on the frame.
 
G

gregoreo

Member
Thank you very much! I'm hoping soon to get to finish building my quad, my only real challenge will be controlling the quad once it is built. You see, I am not going to use a conventional controller and receiver, I own a Raspberry Pi which I plan to use to remotely and autonomously control my quad via either WiFi or Bluetooth from by Android tablet (I don't plan on taking the quadcopter far from me because I am afraid something might happen to it). Once I complete the build and basic programming, I will try to create a more advanced autonomous system with (hopefully) GPS, auto landing and take-off, advanced auto correction (one that is very sensitive to change and can hopefully recover the quad if it is ever flipped over).
I was inspired to do all this because I went to Carnegie Mellon (just a tour) this year, and the guys working on quads told me that it was impossible to recover from getting flipped over (180 degrees) by an external force, or for the quad to put itself upright if it starts off, upside-down. But I have seen quadcopters do flips in the air before, so I am sure that it is possible for me to figure something out. I currently have a gyro and accelerometer to use, so those will be put on my initial build to control stabilization. I plan to prove the students at Carnegie wrong if I succeed, or at least get really close to a good solution; then I will share it with them.
 
Mike

Mike

=)
Admin
Damn - sounds ambitious, but I think it can be done as well. I've seen quads do some crazy stuff. In fact:


I started it at 5:10 where he goes upside down and stays controlled, while basically cutting the grass with the props.

*that's a collective pitch quad though.
 
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