Sunny Buddy Solar Charger V13 Hookup Guide

Contributors: SFUptownMaker
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Heads up! If you have an older version of the Sunny Buddy (V1.0 and older), please refer to this hookup guide. For V1.3 and beyond, continue reading. Check the back of the board for the version number.

The Sunny Buddy is a small maximum power point tracking solar charger for single-cell LiPo batteries.

SparkFun Sunny Buddy - MPPT Solar Charger

SparkFun Sunny Buddy - MPPT Solar Charger


This tutorial will help you understand what the Sunny Buddy is, why it’s useful, and how to use it.

What You’ll Need

The Sunny Buddy can’t do anything without a supporting cast. Pair the Sunny Buddy with these buddies to make it work:

  • Solar Panel – Most panels should work, just make sure they produce an output voltage between 6-20V. Our large and huge panels will work; our small panels will work if you connect two of them in series (see the “Hooking It Up” page for details). Panels with a center-positive barrel jack (like those) will be able to plug directly into the Sunny Buddy.

Solar Panel

  • LiPo Battery (single cell) – The Sunny Buddy is intended to charge a single Polymer Lithium Ion cell. LiPo’s come in all shapes and sizes, we recommend you use one with a capacity greater than 450mAh (e.g. 850mAh, 1000mAh, or 2000mAh). Batteries like those, with a JST termination, will plug directly into the Sunny Buddy. The 450mAh size suggestion is due to the charge rate of the Sunny Buddy–most LiPo cells don’t like being charged faster than their equivalent capacity.

A LiPo battery

  • A Load – Your battery has to power something, right? Your load can be anything from an LED to an Arduino-powered robot.

Suggested Reading

Here are some other tutorials you may find useful before delving into this hookup guide:

  • Batteries – Check out the battery tutorial for some help understanding why the Sunny Buddy works only with LiPo batteries.
  • Electricity Basics – It may be useful to review how current and voltage combine to transmit power to a load.
  • How to Power Your Project – Solar power and batteries are just one of many ways to power your project. Make sure to consider all possibilities!