What difference would be noted between using a 800Kv to 900Kv motor (Tiger T-Motor MT2216-12 vs T-Motor MT2216-11 ) on the exact same frame and using the same 12.45 props? I mistakenly bought the 900s but thought to try them anyway.
I currently use the 800s on my Hexacopter but will use these new 900Kv motors on my new quad. Flyweight about 2.3Kgs ( http://www.foxtechfpv.com/glyder-600-quadcopter-aerovideofpv-platfo... )
I mostly want to use 3S lipos to keep with the family of batteries I use for my other copters.
What would be the pros and cons using the 900Kv motors compared to the 800Kv ones?
Replies
The 900Kv Motors will spin the props faster and produce more lift, but with the same props they will use slightly more energy to do so.
R_Lefebvre gave me this advice on motors/props:
The KV is how fast the motor wants to run at no load. As you load it, it slows down from that no-load speed. As it gets slower, it tries harder and harder to go faster, so it does more work as you load it more. As you load it more, the power that it is making increases. This can go on, until the point that you reach the power limit of the motor. If you exceed the power limit, you will burn out the motor. You also have to be aware that as you load it more, and thus increase the power, you also increase the amperage being used, and you can also burn out the ESC if you reach it's amp limit before you reach the power/thermal limit of the motor.
So all else being equal, meaning the same ESC, the same battery, and the same prop, the motor with the higher KV will make more power at full throttle. This is because it is trying to spin the prop faster than the slower motor does, which necessarily means that it is going to use more power. Therefore, a higher KV motor will make more power with a given prop. I have also found a tendency where a given motor construction (same manufacturer, same size, but different KV windings) tends to show that higher KV motors also can withstand higher loads, they are rated for more power. I'm not quite sure why this is.
So it would seem like the obvious answer is to use a motor with higher KV. They make more power with a given prop, and they can withstand more load/power. This is true if your goal was power/weight.
However, if your goal is efficiency, then it is more efficient to turn the prop slower. That is, thrust/watt.