Goal

The goal of this Mono iteration is improvement of the power supply setup. In the previous post it was mentioned that the Raspberry Pi and other infrastructure would be supported with two separated sources.

Single battery with huge capacity and 7.4V voltage

I came up into solution with Li-Po battery which is known as long lasting power supply.

This is a battery up to 5200 mAh capacity and 7.4V voltage. It should be enough for the purposes (4 DC motors accepting 3V - 9V and Raspberry PI).

Step down to 5V

Here is a tiny module (DC-DC step-down 6-24V to 5V) for reducing the voltage till 5V with convenient USB connector.

Put all together

What I want to build:

• a compact module;
• which couples battery and the step down component;
• has number of additional terminals / connectors for 7.4V and 5V.

Here is what I built for a time being. Here blue terminals supply 7.4V and black headers supply 5V.
The “Dean” (red-brownish) connector serves battery communication.
And step down module with the USB connector is for the Raspeberry Pi.

Things to improve

There are some points I would like to elaborate in future:

• add a polarity guard for blue terminals;
• add a switcher to have ability quickly turn-off the entire circuit;
• add a voltage reading sensor in order to control battery discharge and handle such an event accordingly in software.