What is it?

This is one of the prototypes made for the upcoming Burgduino Modular Charger/UPS system. It is a 1S1A TP4056 based lithium battery charger with a 5V fixed output to power the arduino connected to it plus a 3.7-12V adjustable booster to power external loads.

Why did you make it?

This is a prototype, It is supposed to be part of a bigger project but works fine as is (it is designed to function on its own as well).

What makes it special?

This small shield is a 1S1A lithium battery charger (Li-Ion/Li-Po). It will charger a battery while providing power to an Arduino and/or external load. It has a fixed 5V/1A max output connected to the arduino 5V power pin and also an adjustable 3.7-12V/1A max boost converter which can power external load. This adjustable booster can be enabled/disabled by the arduino as well as from onboard switch. It offers over voltage - over current and over discharge protection for the battery and also temperature protection. The temperature protection can be bypassed with onboard switch, otherwise the charger will not function unless a 10k NTC is connected. The Charger/UPS shield drives three measurements to A1-A2 & A3 analog pins of the arduino allowing it to monitor Battery Voltage, Adjustable boost converter voltage and Charge current. THESE connections are designed to be optional with three solder jumpers at the bottom of the pcb to enable them... THESE SOLDER JUMPERS ARE PRESENT BUT NOT CONNECTED TO THE A1-2-3 PINS... To use them, they must be bridged and three small bodge wires or leftover component pins even better, have to be soldered between them and the A1-2-3 pins. This is the only actual problem with this prototype which otherwise functions very well.

The prototype can be used as is on its own as a battery charger or together with an arduino as a UPS for it.