4.2v solar charger with MPPT

30 Jun 2019

We’ve just published one of our time-tested designs from a previous version of Sensorable 4G Camera.

Check out this Github repository: https://github.com/sensorable/psu-4.2v-mppt-cccv

6 Li-Ion cells + 4.2v MPPT PSU + 20w solar panel = stay powered for longer

We used that design for security and monitoring application. It is a different power use profile from ANPR:

  1. Less computation and less power is needed
  2. Intermittent use
  3. 6 cell battery pack

The interesting feature of that design is that it allows charging at the maximum rate when the sun is out, but will still trickle-charge on a cloudy day. This was achieved by using a microchip with MPPT function that adjusts the charging rate to match the amount of energy available from the sun at that very minute.

Normally, you woudn’t find an MPPT charger for such a small battery pack. They are more commonly used on house-sized installations or larger. Also, the cost of the design and components is a factor. Our electronics designer did a great job of fitting a lot of features into such a small form factor while keeping the BOM cost to a minimum.

This design has been in operation since Feb 2018 and proved to be effective and reliable.

  • See our GitHub repositories for more detail

Head to https://github.com/sensorable/psu-4.2v-mppt-cccv for more info.