This is 7th video in this quadcopter build series and it's about battery voltage alarm setup on KK2.0 flight control board. This is optional step, but it's highly recommended.
We all know the importance of proper handling a LiPo battery. One important thing is not to discharge a LiPo battery under around 3.3V per cell. In air RC we don't like LiPo cut-off feature because, while it saves the battery from excessive discharge, means crashing your craft (and the battery). So, we like alarms. Something that will warn us when to land, but it won't force us to do so.
KK2.0 board has a voltage alarm feature although it's not all that obvious. This video will show you how to properly setup this feature.
In order to alarm you when your battery is about to die, board needs to know what is the battery voltage at all times. By default, this is not possible since only power source connected to the board is constant 5V BEC. So, you need to connect positive and negative wire from the battery directly to the board. In this video you'll see how to do this neatly and safely and where to find those connection points on the board.
Biggest advantage of using KK's voltage alarm instead of separate/external voltage alarm is reducing weight and saving space. Also, besides the fact that the board will alarm you when your battery reaches set voltage, it will also beep faster as the voltage drops lower.
1. While you're doing this, you might as well solder one more female JST connector so you'll have easy access to battery voltage (3S/4S) if you'll need one in the future. I know I will so I've soldered one more JST connector to other terminal on PCB board.
2. As I said in many previous videos, on JST connector 2 means positive (+), and 1 means negative (-). So make sure you do this correctly.
1. Despite the fact that this is highly recommended and simple modification, you have to be aware that you are handling very sensitive electronics and that excessive heat will damage components on the board or/and the board itself. So, try to solder this as quickly and carefully as possible to ensure you won't damage anything.
2. Using black wire for both positive and negative is NOT recommended. You could confuse them later and create some damage. Use red wire for positive instead! Only reason why I'm using black wire for both is look. This quadcopter will be black and white and red wires are not an option for me. As long as you understand the risks involved, you can do the same.
KK2.0 flight control board
JST male connectors
JST female connectors
Servo wire (26 AWG)
Soldering Iron (30W)
Third/helping hand tool
Enjoy RC as much as I do! :)