Issues running on 12V input without a battery

I am having trouble using 12V input to the UPS hat on J4, with the UPS hat attached to a Raspberry Pi 4B+. My symptoms are as follows:

  • From 5V to somewhere around 8.5V, the UPS Hat functions as I expect, and the RPi boots, whether there is a battery installed or not.
  • With a battery installed, the UPS Hat functions as expected including J4 input voltages up to 12V.
  • Without a battery installed and input power >8.5V, the Hat initially outputs 5V for 5-6 seconds, but then the output power abruptly drops to 0V. Obviously, the Pi does not boot fully.

I’ve seen this behavior on 100% of the Hats I’ve looked at so far (4 total.) Is the UPS Hat not expected to function above a certain input voltage without a battery (and if so, can you please tell me why?) And if this is the case, is it likely to function with a dead battery installed? I plan to use a battery, but my systems will be in remote locations, possibly powered down for long periods of time, so it is possible the 18650 will be fully drained when input power is applied.

Hi @8bitnintendo,

UPS HAT works on dead batteries. In addition, it is designed to work even without a battery.
We tested and did not see it with any problem. What is the current capacity of the 12V source? (We recommend 1.5A for 12V)

Do you have account? If you do not have an account, you can create one by clicking here?
Please go to the Configuration tab and find the Firmware Update and Software Update section. Keep them up-to-date to have a better experience.

After the installation is completed, please share the screenshot of the dashboard.

Thank you.


I am using a BK Precision 9202. I have the current limit set to 3.0A. During normal operation with all my peripherals (but no battery), it runs at about 1.2-1.4A (using 5V.)

The firmware is now updated from 0.2.3 to 0.2.7. Behavior with respect to 12V input has not changed…