Voidbox Industries’ Chloe Madison has launched a crowdfunding campaign for the PwrTool 500, a 60V 500A power and battery monitor designed to easily integrated into Home Assistant.
“PwrTool 500 is an open-source battery and power monitor designed for off-grid energy systems,” Madison explains of the project. “It integrates seamlessly with Home Assistant and supports direct customization via ESPHome or your own firmware. Designed for most 12–48 VDC systems, PwrTool 500 is built to handle up to 500A peak current across 6–60 VDC, and provides detailed insight into your energy flow, generation, storage, and usage so you can monitor and automate data-informed actions.”
Madison first unveiled the PwrTool 500 around a year ago, revealing a design built around the Texas Instruments INA238 16-bit power monitor chip with a Voidbox FLIP_C3 Espressif ESP32-C3 microcontroller board and ambient temperature and humidity monitoring alongside the promised power monitoring capabilities. There’s an 45W N-channel MOSFET for lighting or load control, and Qwiic/STEMMA QT compatible expansion for external sensors — or to daisy-chain multiple PwrTool 500s together.
“Conventional ‘smart shunts’ lock your data into proprietary apps and ecosystems,” Madison says of the reason for designing something new. “Even when modified, they typically require decoding undocumented protocols. PwrTool 500 is different thanks to its fully open hardware and software. With direct access to the sensors, firmware, and GPIO [General-Purpose Input/Output], you can configure PwrTool 500 to meet your system’s exact requirements with no vendor lock-in.”
The PwrTool 500 is designed to connect to Wi-Fi then automatically register itself in Home Assistant thanks to a pre-flashed ESPHome firmware, and there’s a header for switching between hot- and cold-side installation. As previously promised, it’s also open-source under the Creative Commons Attribution Share-Alike 4.0 license with an EasyEDA Pro project file containing a schematic, board layout, and bill of materials available on the project wiki — with a separate project file available for the FLIP_C3 microcontroller board at its heart.
Those interested in picking up a ready-to-use unit rather than building their own, meanwhile, can do so on the project’s Crowd Supply campaign page, where hardware is available for $149 with free worldwide shipping; all devices are expected to ship in late April next year.