Tag Archives: LiPo

SODAQ ONE board – GPS + LoRa + Solar charger

This is the third generation of our succesful SODAQ ONE board. It is equipped with a solar charge controller and runs on a LiPo or a permanent battery. It has the Ublox Eva 8M GPS module which is not only miniature but with it’s assisted GPS feature it can get a fix within seconds. We’ve now added an extremely low power Accelerometer/Magnetometer. This gives the board a nifty feature where it can stay in (deep) sleep mode until it moves. An essential feature for developing low power devices.

Let’s imagine you want to develop a bicycle tracker using the SODAQ ONE. You would like to track the position of the bike, but only when it has moved. This is possible if you keep the device in deep sleep until it detects motion. If the motion continues for a while, the bicycle may have changed position so only then the GPS will switch on to get a new reading and send this location over the LoRa network. Efficient right? This system will allow you make most efficient use of your battery capacity by only using the GPS when really needed, essentially increasing the battery life of your system.

SODAQ ONE board – GPS + Solar charger board – [Link]

Torpedo 2 – a cheap & powerful 3A DC/DC converter with built-in charger

Boris Landoni @ open-electronics.org presents their second version of Torpedo, a kind of DC-DC converter able to provide 5V output from a variety of sources. He writes:

Some time ago we had introduced you to the Torpedo switching power supply, a particular kind of DC/DC power supply called SEPIC capable of supplying 5 V from several external supply sources, such as an external voltage between around 3.5 and 20 V, the 5 V coming from a USB connector or the 3 to 7 V supplied by a LiPo battery. The very small power supply also had a circuit capable of charging the battery up through external sources, where available.


  • triple power source: USB, LiPo battery and an external source;
  • a wide range of input voltage values: 6,5 – 18 V;
  • can supply a maximum current of 3 A;
  • high efficiency, even over 85-90%;
  • built-in charger for LiPo single cells;
  • can switch from battery-powered to another source without interruption;
  • 5 V output with high stability when load varies and low ripple;
  • possibility to turn off the only output leaving the step-down converter and the charger active;
  • possibility to automatically deactivate the output if power supply comes from the USB connector which is limited to 500 mA current by the specs; if there is a battery, power supply is granted by that;
  • status LEDs indicating charge, the power supply used, output activation and so on.

Torpedo 2 – a cheap & powerful 3A DC/DC converter with built-in charger – [Link]

Versatile And Open Source LiPo bBattery Breadboard Power Supply

Orlando Hoilett from Calvary Engineering LLC designed a  versatile Li-Po battery breadboard power supply and wrote an Instructables on it. This power supply outputs 3.3V to the breadboard and takes input from a single-cell LiPo battery. The breadboard power supply also has the ability to charge the battery without needing to separate it from the circuit board. More importantly, this project is licensed under Open Source Hardware which means anyone can modify, distribute, make, and sell this design.

LiPo bread board power supply
LiPo breadboard power supply

Key Components

The complete BOM is available at the GitHub repository.

  • JST connector
    This connector connects directly to the LiPo battery.
  • 3.3V regulator, AP2210K
    3.3V logic is getting increasingly popular among electronics hobbyists and engineers. Also, boosting 3.7V of a LiPo battery to 5V can induce quite a bit of switching noise on the power supply. Linearly converting 3.7V to 3.3V is the best way to avoid this problem.
  • Battery Charger, MCP73831T
    This power supply has a charger built into the board so you can charge the battery without removing it from the power supply.
  • Voltage Selection Jumper
    The voltage selection headers are 3 pin male headers and they are labeled as 3.3V (or VReg) and VRAW (or LiPo). Connect the center pin to 3.3V to get power from the regulator. Connect the center pin to VRAW to get power directly from the LiPo battery.
  • DPDT Switch
    This switch lets you power down the board without removing the battery.
  • LED indicators
    LEDs are used to indicate the current status of the board.


This board breaks out the LiPo battery to the breadboard power rails on both sides. It has a DPDT switch to power down the board. The AP2210K IC has an ENABLE pin which is pulled down to the ground using the DPDT switch in order to enter the low power mode. In low power mode, the regulator and all the LEDs get disabled and draws almost no current from the LiPo. More about the AP2210K regulator IC is on this datasheet.

LiPo breadboard power supply schematic
LiPo breadboard power supply schematic

Another great feature of this breadboard power supply as mentioned earlier is, it incorporates an MCP73831T LiPo battery charger IC. It is a widely used PMIC (power management integrated circuit) for charging LiPo batteries. The LiPo battery should be connected to pin 3 (VBAT) and 5V should be applied to pin 4 (VDD).

The chip starts charging as soon as it detects 5V input and stops charging when the battery is full. Charging current is limited to USB standard i.e. 100mA by connecting a 10.2K resistor between pin 5 (PROG) and ground. So, it’s completely safe to charge the battery from your laptops USB port. Other host microcontrollers can check the battery status using pin 1 (status pin) of MCP73831T.

A 32-BIT FISHINO board with WiFi, SD card, RTC, audio codec, LiPo and more

Boris Landoni @ open-electronics.org presents his 32bit Arduino Compatible board which has some nice features on board. He wrties:

Our prototyping board acquires a 32-bit processor and sets the bar high, towards demanding applications that may take full advantage of the WiFi support, of the RTC and of the SD-Card, that make Fishino stand out from the common Arduino UNO. Second installment.

A 32-BIT FISHINO board with WiFi, SD card, RTC, audio codec, LiPo and more – [Link]

Solar Power Module v2

Chip McClelland @ hackster.io published his solar li-po battery charger based on MCP73871 to manage the solar and DC charging of the LiPo battery, TPS63020 Buck-Boost Converter and Maxim 74043 LiPo Fuel Gauge. He writes:

I build connected sensor which are often deployed in local parks where there is no access to utility power. Over the past couple years, I have been refining and testing my solar power modules and have arrived at this compact integrated design. I have a number of these deployed and they have been in continuous service for up to two years. I wanted to share this design in case it might be helpful for your projects. I would also greatly appreciate any input or suggestions on this design so v3 will be even better.

Solar Power Module v2 – [Link]

BQ25504 Solar Cell LiPo Charger

by Pesky Products @ tindie.com:

This is a small (0.5 x 0.5 inch) breakout board for Texas Instrument’s BQ25504 Ultra Low Power Boost Converter with Battery Management for Energy Harvesting Applications.

BQ25504 Solar Cell LiPo Charger – [Link]


An Introduction to LiPo Batteries


Average Man Vs Raspberry Pi has a handy article on LiPo batteries.

LiPo batteries – to fear or not to fear? Up until very recently, I was petrified.

Whilst most other competitors at Pi Wars 2015 were happily using this angry and volatile battery technology, Average Man over here was assuming he was playing it safe using heavy NiMH battery packs in AverageBot.

I was first introduced to LiPo (‘Lithium Polymer’) batteries during my days playing with RC cars. At that time they seemed to have the label of “an advanced new battery technology that needs expert care or they’ll blow your face off“. That was enough to put me off, I’m far too pretty.

Fast forward many (I won’t say how many) years and LiPo is commonplace –  the world seems to have forgotten how dangerous these little 3.7V packs are – or maybe the technology has improved?

An Introduction to LiPo Batteries – [Link]

SparkFun Battery Babysitter

The SparkFun Battery Babysitter is an all-in-one single-cell Lithium Polymer (LiPo) battery manager. It’s half battery charger, half battery monitor, and all you’ll ever need to keep your battery-powered project running safely and extensively.

The Battery Babysitter features a pair of Texas Instruments LiPo-management ICs: a BQ24075 battery charger and a BQ27441-G1A fuel gauge. The charger supports adjustable charge rates of up to 1.5A, as well as USB-compliant 100mA and 500mA options. It also features power-path management, guaranteeing power to your project even if the battery has died. The self-calibrating, I2C-based BQ27441-G1A measures your battery’s voltage to estimate its charge percentage and remaining capacity. It’s also hooked up to a current-sensing resistor, which allows it to measure current and power! It’s a handy IC to have, if you ever need to keep an extra eye on your project’s power draw.

SparkFun Battery Babysitter – [Link]