How do I add more devices by pulling voltage from existing outlets

[Menzee]

I have a power distribution board for my Quadcopter. It is powered by a 3s Lipo and the following are connected:

• 12 Volt outlet for ESCs: 4 ESCs 12 Amp
• 5V Outlet: Connected my 5V Gyroscope and Arduino Nano
• 12 V outlet: Connected a receiver using 3.3 V regulator.

I don't have any additional outlets.

Question is, how do I add more devices by pulling voltage from existing outlets by connecting in parallel, as the Volts will be the same. I understand Amps will get divided.

• Is it ok, to add more devices in parallel to let us say my 12V outlet, where I connect couple of more 3.3 V regulators to run 3.3 V devices and couple of 5V regulators to run 5V devices.

Based on the specification of LIPO and power dist module below, is there a way I can determine the max devices I can connect to both 5V and 12V outlets on my power distribution module?

here is the spec of my power distribution module:
General:

• Input voltage range (3S-4S LiPo operation): 9 - 18V DC
• Regulated 5V and 12V outputs
• 6 ESC outputs & 1 pair VCC/GND pads

ESC outputs:

• Continuous current: 25A*4 or 15A*6
• Peak current (10 seconds/minute): 30A*4 or 20A*6

BEC 5V output:

• Designed for RC Receivers, Flight controllers, OSD, and Servos.
• DC/DC synchronous buck regulator.
• Voltage: 5.0 +/- 0.1VDC
• Continuous current: 2 Amps (Max.2.5A 10s/minute)
• Output Ripple: 40mV (VIn=16V, VOut=5V@2A load)
• Short-circuit tolerant (5 seconds/minute)

BEC 12V output:

• Designed for Video TX or FPV camera with linear regulator(www.kynix.com/Product/Cate/618.html).
• The battery should be 4S LiPo (13~18V DC)
• Voltage: 12.0 +/- 0.3VDC
• Continuous current: 500mA (Max.0.8A 5s/minute)
• Short-circuit tolerant (2 seconds/minute)

BEC 12V @ 3S LiPo

• Output voltage= 3S LiPo voltage -1V

 

[durok]

This isn't an aviation R/C site, it's a R/C rock crawler land vehicle forum...

I recommend you try using Google to find the proper forum for your question.

 

[Hydrocarbon92]

First off, you calculate how many things you can power by the continuous amps needed by all of them MINUS the continuous amps the regulator on the distro block can provide. For 5V it's 2 amps continuous, for 12V it's 0.5 amps but only if using a 4S. You answered your own question on adding devices - you wire more in parallel to the existing devices. Use a y-harness or solder wires on top of the existing devices' wires.

Since it's a 3S battery, you shouldn't use the 12V BEC output for any device unless it absolutely can't run on more than 12.0v (most 12v devices can do 13-14v max). When you power a linear regulator, the max out put voltage will be 1v less than input, so on 3S max will be 11.6v to start and 9.8v when the battery is empty. The additional 5V and 3.3V regs should tie into the INPUT of that distro block to get power direct from the 3S battery. Running a regulator off a regulator just compounds inefficiencies.

If you need to extract the max runtime from the battery, look for "switch-mode" regulators. Linear regulators get more inefficient, in a near-linear fashion, as output drops below input. A 5v reg fed from 12.6v dumps over 150% of the power used AS HEAT. A switch-mode reg would only dump about 10-15%.