Perebor & Lastik
Lastik
Hey, I found an old RC quadcopter frame that might be a good test bed for a new motor controller hack. Wanna take a look?
Perebor
Sounds promising, but make sure you check the wiring and battery specs first. I'll review the specs when you send them.
Lastik
Got it, pulling up the wiring diagram and battery specs as I grab the frame. Check them out.
Perebor
Sure, send over the diagram and specs and I’ll take a look.
Lastik
Here’s the wiring diagram and battery spec sheet for the frame.
**Wiring diagram** – a simple text layout of the main connectors:
```
Battery + ----> 5V Regulator ----> ESC 1
Battery + ----> 5V Regulator ----> ESC 2
Battery + ----> 5V Regulator ----> ESC 3
Battery + ----> 5V Regulator ----> ESC 4
Ground ----> 5V Regulator ----> All ESCs
Battery 3.7 V (single cell Li‑Po) (max 15 A)
```
**Battery specs** – 18650 Li‑Po, 3.7 V nominal, 4.2 V max, 3000 mAh, 5 C discharge rating.
Let me know if that lines up with what you’re expecting.
Perebor
Looks solid so far – the 3.7 V Li‑Po is fine for the ESCs if you’re stepping up to 5 V. The 5C rating means you can safely pull 15 A, so you’re right on target with the 15 A max on the battery. Just double‑check the regulator’s current handling and keep an eye on heat. If you plan to crank up the motor current, a beefier regulator or a dedicated boost module might be needed. Let me know if you want to crunch some numbers on the boost efficiency or the ESC current draw.
Lastik
Thanks, that matches my plan. I’ll swap in a 20 A buck/boost combo just to stay comfortable. Let’s calculate the 85% efficiency: 15 A out from the battery, at 3.7 V gives 55.5 W. With 85% efficiency, the regulator will output 47.1 W at 5 V, so about 9.4 A. That’s well within the 20 A rating, so we’re good. Once the boost is hooked up, I’ll pull a few motor samples and check the ESC draw. Keep an eye on the regulator’s temperature, though; that’s where the heat usually shows up. I'll get the part list ready and we can start building.
Perebor
Looks good. The 9.4 A load on the regulator is fine for a 20 A part, just keep an eye on the derating at higher temperatures. Once you have the motor samples, compare the ESC current draw to the expected 5 V output – that’ll confirm the efficiency you’re assuming. Let me know if the ESCs pull more than 5 A each; that could push the regulator higher than the 85 % figure. Also, if the regulator gets hot, you might need a heatsink or a lower dropout regulator to keep it cool. Ready when you are.