High efficiency lipo charger with integrated fuel gauge sensor

This is the second generation of the high-efficiency lipo charger with an incredible efficiency of up to 94%! It allows charging a single lipo from as little as 200mA up to a whooping 2A for massive lipos. With an integrates lipo fuel gauge IC (MAX17048), you can accurately tracks the voltage as volts or as percentage or even set up alerts.

Why did you make it?

Based on some good feedback from users who were interested in the previous revision of the high-efficiency lipo charger, some users suggested a new revision with an integrated fuel gauge IC, since often, the battery voltage needs to be tracked from a micro-controller and normally requires yet another pcb. This version aims to solve both of these issues in a single pcb, while also being more user-friendly and packed with more features.

What makes it special?

To improve user-friendliness, it offers the following improvements compared to the last revision:

• two LEDs instead of one. The first one shows if the board has power, the second one is the status led of the lipo-charger IC
• integrated JST connector and optional pads for lipo (+ and -). This means you can connect a lipo directly by soldering or via the JST connector
• short-circuit and over-voltage protection on the JST connector. This can save your lipo and this pcb!
• Adjustable charging current without soldering by setting the integrated DIP switch
• integrated fuel gauge IC (MAX17048) with a stand-by current of only 3uA! This chip has several libraries available (e.g. Adafruit) and can be interfaced via I2C, hence only two pins are required
• hackable via bottom pads. For the tech-savvy with good soldering skills, it's even possible to break out the integrated LED, set a custom charging current via a resistor or disable the power LED
• small form factor of only 30x30mm and slim pcb (1mm) allow for a total height of only 6mm
• low deep-sleep current. Although it packs two ICs, when idle, only consumes max. 10uA.