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Autonomous Solar Powered System

A project log for Arduino MPPT Solar Charge Controller

The charge controller consists of a buck converter that is controlled by an Arduino via a half-bridge driver.

tobiasTobias 04/29/2016 at 00:030 Comments

The MPPT charge controller works pretty well by now, but there are a few more steps necessary to make this an autonomous system that does not require human intervention. I added a power controller board that takes care of that. To reduce internal cables and screw connectors, I added two Arduino headers that quickly connect and disconnect the two boards (picture on the right).

One of the important aspects is that the battery will not get drained over time; for that purpose, I added a relay that completely disconnects the battery when its voltage drops below a threshold. The relay itself is powered by the Arduino through a transistor.

The system can be powered up either by the solar panel (when the sun comes up and sufficient power gets into the buck converter which turns on the Arduino) or by pushing the button that bypasses the relay until the Arduino keeps the relay powered on.

In principle, it should be possible to use this design for a planetary rover that spends days, weeks, or months inside a container without sunlight and wakes up when the solar panels receive sun light. It continues to work even after the battery has deteriorated.

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