Stubborn Stamina LF: The Unstoppable LFP UPS for Raspberry Pi
The uncompromised LiFePO4 power for Raspberry Pi. No jumpers, no settings, no failure. Just relentless uptime.
Why Stamina LF?Built to Last, Not to Adjust.
The Stamina LF was created for one mission: to provide the most reliable, fail-safe LFP backup for Raspberry Pi without the complexity of industrial setups.
Pure LFP Safety
We chose LiFePO4 for its 2000+ cycle life and thermal stability—no fire risk, no compromise.
Plug & Play Simplicity
Standard 5V USB input. No jumpers, no settings, no specialized power supplies..
Focused Reliability
By stripping away unnecessary features, we reduced heat and failure points, creating a robust, affordable powerhouse.
Stubborn Stamina LF: Design Choices
Pure LFP Safety
We chose LiFePO4 chemistry specifically for its 2000+ cycle life and maximum thermal stability. It provides a safer, more durable energy storage solution than standard Li-ion, lasting for a decade even with daily use.
Dual-Stage Efficiency
Offline Topology: Near-zero energy loss during normal operation. High-Efficiency Boost: Advanced converter technology extracts every second of backup time from the LiFePO4 cell when it's needed most.
Built to Last
Hardware-only control. No jumpers, no firmware, no complex setup. It works immediately.
Avoid SD Corruption
Prevents file system damage. RPi only powers when sufficient time is available for a graceful power cycle.
Anti-Stuck Shutdown
Eliminates 'zombie states.' If power returns during shutdown, the hardware forces a power cycle to ensure a clean reboot.
Direct GPIO Signaling
Easy programming. Avoids extra load on the capacitance-limited I2C bus. Uses only 3 dedicated GPIO ports for clean, instant status signaling.
5V USB-C Optimized
Simplified power path for standard setups. Cooler operation, lower cost.
Silent Watchdog
Alerts your Raspberry Pi on power loss and low battery for graceful shutdown.
No Restart Loops
Prevents infinite boot cycles by waiting for a safe power threshold.
Stacked Power
Keeps all GPIO pins accessible for other boards.
Solid Connection
Massive, soldered 40-pin header. No pogo-pins, reliability isn't a gamble.
Battery Protection
Reverse polarity and NTC protection with red LED alert for incorrect insertion.
Manual Override
High-Performance "ON" Mode: Instant power-up and maximum capacity for power users. Note: Safety features are lost in this mode.
Stubborn Stamina LF: User Interfaces
2x20 pin connector.
Reset.
Push-in terminal.
Potmeter setup.
5V supply & charging.
Input status.
Thermal protection.
AUTO-ON-OFF.
Level indicators.
Holder fixing points.
Stubborn Stamina LF Pin allocation
Stubborn Stamina LF Technical specs
Energy storage Device
- Energy storage
- LiFePO4 battery
- Charge cycle
- 3000
- Operation temp.
- -20..+60 ˚C
- RPi4 idle backup*
- 319 min
- RPi4 full load*
- 133 min
- RPi5 idle backup*
- 268 min
- RPi5 full load*
- 126 min
* in case of 4000mAh battery
Physical parameters
- Form factor
- Raspberry Pi HAT
- Dimensions
- 65x56x23 mm + 11mm header
- Stackable
- Replaceable battery
Electric parameters
- Charging current
- 2A
- Maximum discharge current
- 7.5A
- Maximum load current
- 3.5A
- Output voltage
- 5V
Power Supply
- Main Input (USB-C)
- 5V
- Auxiliary Input
- USB PD (RPi5)
Communication
- Method
- 3 GPIO port
- GPIO port allocation
- 1 option
- Disabling option
Connectors
- Main power input
- USB-C
- Auxillary power input
- Reset
Setup
- Mode options
- AUTO-ON-OFF
- Adjustable level threshold
- Adjustable input voltage threshold
Safety
- Reverse polarity protection on battery connector
Control
- External control of the power of Raspberry Pi
Indication
- Input Power
- Battery voltage level
- 4 LEDs
Software
- Control software
- C++ & Python
- Open source
Stubborn Stamina LF Manuals & Resources
Github
More information, user manual and control software (C++ & Python) can be found on Github.
Stubborn Stamina LF Gallery
