We previously designed the Pi18650 HAT which holds a single 18650 Li-Ion battery providing remote power and UPS capabilities. Many of our customers liked the design but some users and companies designing other products were requesting more power and the ability to have two batteries in the holder. The Pi18650 DUAL BATTERY HAT was born. It doubles the output power and allows battery switching on the fly. Great for those remote and outdoor applications or where no power outlets are available.
The Pi18650 is an add on HAT which plugs into the 26/40 pin connector on the Raspberry Pi. This HAT allows you to operate your Raspberry Pi without a power cable and can use various capacity 18650 Lithium Ion batteries. On board are two 1A battery charging circuits for charging the batteries individually. The Pi18650 development board also includes a 4x2 100mil header for use with a ESP8266 (ESP-01) wifi module for remote monitoring and CLOUD integration or a custom designed board. Included is one additional stacking header for extra clearance when stacking other HAT's on top of the Pi18650 DUAL BATTERY HAT. How Long Can The Pi Last? As an example the Raspberry Pi Zero uses approximately 87mA without and 103mA with a USB dongle plugged in. With a fully charged single 3000mAh battery, the Pi would last 34.5 Hrs with nothing attached. Using two batteries would double the run time.
The Pi18650 DUAL BATTERY HAT has additional features added to the single battery version. As with two batteries the design becomes more complex and we have added an LED indicator to show the battery has power and connected to the load. A comparator circuit monitors the battery voltage level and when it gets too low it will be automatically cut off from the load with a small current drain on the battery giving it longer standby time before being recharged or replaced. The batteries can be swapped on the fly by the user.
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The Pi18650 DUAL BATTERY HAT holds two single cell lithium Ion 18650 form factor batteries which should have integrated battery protection circuits. The boost circuit maintains the voltage to the Pi at 5.1V for battery voltages of 3.7V to 4.2V. The jumper allows you to disable power to the Pi and Isolate the battery circuit or start the Pi. This jumper can be used with an external relay providing automatic control from circuit or system. It also includes two charging IC's which can charge up to 1A from the USB Micro connector and has two battery monitoring IC's which communicates to the Pi via I2C. We have coded a Python script using I2C SMBUS for you to read the battery status along with a shutdown script for low battery voltage. Charging LEDs show the status of the charging process. The Pi18650 DUAL BATTERY HAT can also be used with other development and SBC boards. Any DC power supply, adaptor or solar panel up to 18V max can be used with the charger. Use a good quality USB Micro cable as we found the flat style thinner cables did not work well with the charger and current was limited. The thicker round USB Micro cables work well.
STAT2 (OFF) - Pre-Conditioning or Fast Charge Mode
STAT2 (ON) STAT1 (OFF) - Charge Complete
PWRGD (ON) - Power Is Good For Charge
- 1A Charge Current Max for each battery
- Up to 6A for Raspberry Pi via Li-Ion Batteries
- Up to 18V DC Input for UPS and Charging
- I2C Battery Monitoring (Python Script)
- DUAL 18650 Single Cell Lithium Ion Holder
- 26/40 Pin Connector for Raspberry Pi
- USB Micro Connector for Charging
- Jumper for Pi On/Off/Charge
- Voltage Regulation 5.1V
- Use as a UPS or with Solar Panel
- Wifi Header for ESP8266 (8 Pin) or Custom Board
- Additional Micro USB connector for powering other devices
- Screw Terminal for powering external boards
- A 3-Pin Jumper to Switch USB Micro and Terminal Connection
- Individual Load Cutoff Circuits for Low Battery
- Standoffs Providing Support (with charger perk)
- Reverse Battery Protection
- Battery To Load ON LED's
- Power Robots, Motors and More