This is an overview of the hardware including the overall design and the specifications used to calculate every component.

We will also need to test all of the hardware to ensure it meets the specifications.

This is part of the open-source charge controller project.

Hardware overview

As show in the overview, there are a number of parts to the system:

  • Microcontoller – the ‘brains’ of the device. This will make decisions based upon the voltage monitoring to control the power stage.
  • Voltage monitoring – monitors the voltage
  • Power switching – MOSFET and MOSFET driver – this will control the power from the input to the output.
  • Power supply – provides power to the circuit. Must be efficient.
  • Protection – Diode, fuse and over-voltage – Ensure that the device will not be damaged from incorrect installation
  • ISP:  In series programming – The microcontroller can be reprogrammed easily without expensive equipment.
  • Current monitoring – for information and user interface (this is optional)
  • Display – LEDs will show the system status. This could also be an LCD display. (this is optional)
  • Data – output data as a serial data stream for use by other devices (this is optional)

An overview of the system is shown here:


We have also listed the specifications and ratings for the components:

Design specifications

  • Battery bank nominal voltage: 12 – 24 DC, (up to 48V would be good).
  • Actual voltage range: 10-32V DC, (or up to 65V DC for 48V system).
  • Current range: 0 – 20A DC
  • Required options (must have):
    • Re-programmable
    • Adjustable set-points (different types of batteries)
    • Reverse polarity protection
    • Over current protection
  • Useful options (nice to have):
    • Battery voltage indication,
    • Could be either series or shunt regulator,
    • Low Voltage Disconnect,
    • Voltage display,
    • Current display,
    • On-board data storage,
    • Maximum power point tracking,
    • Over voltage protection

The menu gives a breakdown of these parts and the design choices made for each section.

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