ELECTRONIC SPEED CONTROLLERS (ESC)
The ESC makes the motors spin. BLHeli_S ESCs have okay performance but lack some features that pilots today usually expect. BLHeli_32 is the latest and greatest. In terms of flight performance, there isn’t much difference between them, but BLHeli_32 is where most development is going now, and we recommend that you use it if possible. BLHeli_S ESC’s are usually a bit cheaper, so if you don’t care about the “advanced features” and just want to fly, BLHeli_S might be for you.
Most pilots today choose a 4-in-1 ESC. This form-factor puts all four ESC’s on a single board, typically installed directly underneath the flight controller. The advantage of a 4-in-1 ESC is faster build with fewer solder joints; typically it will just plug right into the FC. The disadvantage is that if you fry a 4-in-1 ESC, you have to replace all four ESC’s at once instead of just one, which is more expensive.
If you use a 4-in-1 ESC, it’s best to buy one that is intended for use with your FC, since this guarantees that they will be compatible. You can use any 4-in-1 ESC with almost any FC if you’re willing to build your own wire harness to connect them–but that sort of defeats the point. That being said, some ESC’s are so good that I would consider using them with any FC.
If you use individual ESC’s, make sure to buy an “all-in-one” (AIO) style FC.
One of the biggest challenges in buying an ESC is choosing the right size. Here’s some general advice. ESC’s rated for 20 amps are the absolute minimum you should choose for a 5” build. ESCs rated for 25 amps are good for most 5″ props with motors of size 2306, 2207, or smaller. Motors may pull more current than this at full throttle, but you typically won’t spend a lot of time at full throttle, and the ESC’s “burst rating” can handle these short surges. Higher-rated ESCs should be selected if you are using larger motors, higher-kv motors, if you plan to spend a lot of time at full throttle, or if you just want a bit more headroom to help ensure that the ESC doesn’t burn out. Lately, we are seeing ESC’s rated up to 50 or 60 amps. Although it’s unlikely that most pilots will pull this much current, the additional head-room makes the ESC less likely to burn out when flown hard.