Which of these circuits is appropriate for powering a NanoESP32 and motor driver from a single battery?

Projects General Guidance
1

I'm working on building a two-wheeled robot, and want to power both the microcontroller and motor driver off a single battery source.

I want the 2x 14500 batteries (7.4V) to deliver 7.4V to the microcontroller, and 5V to the motor driver through a 5V buck converter.

In the final setup of this project, there will be NO breadboard, so I'm tring to understand how to get the power from the battery to both the microcontroller and driver, without the help of shared pins on the breadboard. All wiring to pins will be directly soldered.

Here are the two circuit options I'm contemplating:

Option 1:

Image
Image2292×1386 117 KB

Here the battery wires are connected to the VIN and GND pins of the buck converter.

The microncontroller is supplied 7.4V by connecting its VIN/GND pins to the VIN/GND pins of the buck converter.

The motor driver is supplied 5V by connecting to the 5V and GND pins of the converter.

Option 2:

Image
Image2296×1386 118 KB

Here the positive and ground wires coming off of the battery are split by soldering on two extension wires to the end of each wire.

One set of wires is connected to the VIN and GND pins of the microcontroller to provide it 7.4V.

One set of wires is connected to the VIN and GND pins of the conveter, which the motor driver is connected to.

I'd like some help understanding the following:

  • Each of these wiring options will corretly provied 7.4V to the microcontroller and 5V to the motor driver, correct?

  • Is there a better choice between these two options and why?

2

Option 2 always.

3

Thanks. Is there a reason why? Would option 1 not work?

4

Both 'work', but the NANO path is a bit longer so some voltage drop. More importantly is noise from the motors MAY cause more problems with the NANO in option 1. I would also consider adding some de-coupling capacitors soldered as close to the NANO +ve pin (your red wire) at least 2 and maybe 3 which you can test if you have a scope or just note bad behaviour. In order, 10uF Electrolytic, 0.1uF Ceramic, and optionally a 1 to 10 nF Ceramic.

5

I think both circuits are the same. In both cases, the Nano and the buck converter are powered directly from the battery. I don't think it matters whether you do this at the battery or at the buck converter.

6

How much will one motor pull from the source?

7

This topic was automatically closed 180 days after the last reply. New replies are no longer allowed.