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Restep Power System

Intelligent Modular Power at 100W Scale

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OSHWA Certified Open Source Hardware

Mother Module - Battery Charger Module - Off-Line Module - PV Module

Restep promotes the conscious use of renewable energy.  It is an intelligent power system that integrates renewable energy inputs, energy storage, telemetry and control.  This open source hardware is intended as a utility and an educational tool.

Somewhere between a LEGO, an Arduino, and a Power Wall, the Restep system provides a flexible environment for powering just about any 100 Watt load.  Data gathered from the system enables intelligent and efficient use of energy.  For example, loads can be engaged when power is directly available from the sun or wind to minimize power loss in charging and discharging the battery.  The battery can be judiciously utilized and prevented from running completely down.  Many deliberate little steps can make big changes.

The Restep power system transmits data via USB.  The data can be transmitted in real-time, or saved in local memory and downloaded later on.  Data can be imported to Microsoft Excel, LabView, or another established data processing software.  An example of the data presentation is shown below.  In this example, the battery was topped-off in the morning, used to power a constant 36W load until it was depleted, and then solar energy recharged the battery in the afternoon.

Above: The Excel dashboard automatically calculates and displays relevant data.  This is just one example of how the user data can be presented.  The software tools here are provided as open-source for anyone to use and modify for their own specific application.

 

Below: Charts show profiles of the battery voltage and charge, system power and energy.  These were generated in Excel, but could be generated with many other applications.  Since this is all open-source, anyone can tailor what data is read from the system and how it is used.

Excel takes the raw data from the micro controller, applies processing and formatting to make it easy to interpret.  The data in the table below is used to build the charts and dashboard above.

Here are just a few ways the data can indicate what is happening in the system...

The snippets below are from the full plots above.

The original application for the Restep Power System is FarmBot.  The idea is that you can power a FarmBot with renewable energy and have some insight as to how much power is available, what is the state of charge of the battery, etc.  The Restep prototype is currently powering a FarmBot, but the applications for the Restep Power System go further.

The Restep power system is designed using open source and/or free software wherever possible.  KiCad is used for the schematic capture and PCB design, LTSpice is used for circuit simulations, PTC Mathcad is used for calculations, and Arduino IDE is used to program the micro controller.  Microsoft Excel is the only licensed component, but it's not entirely necessary.  All documentation is available as open source on the restep-eco GitHub repository.

Documentation includes:

Schematics

PCB Native Design Files and Gerber Files

Simulations and Models

Calculations

Firmware

Sample Data

Database

Color Code

Contributors

Thanks to FarmBot for inspiring and supporting this project.

Thanks to Analog Devices for their support with Linear Technology demo modules.

The LTC4015 and LT8705 are key components in this design.

Thanks to Astha, Brian, and Quyen for their MISO Module Senior Project.
Their work can be found at the Cal Poly Digital Commons here.

EMI Filter

The Restep EMI Filter is an add-on for FarmBot.  This EMI Filter is designed to mitigate WiFi signal degradation while the vacuum pump is operating.  It is another open source hardware project that is documented on the restep-eco GitHub repository.

Please visit the GitHub repository for more information, including the source files, documentation and a user manual.

The hardware is licensed under the CERN-OHL-P v2 license.

All documentation is licensed under the Creative Commons Attribution 4.0 International License.

LTSpice circuit models are licensed under the MIT license.

Below are some photos of the EMI Filter.

© 2021 CHRIS ARNTZEN

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