Trying to power RPI with battery

I am trying to power a Raspberry Pi model 4 through a D24V150F5 5V regulator attached to an 11.1 V Lithium Polymer battery. The power is delivered to the RPI via the usb port where the wall wart would normally be plugged. The RPI green and red lights come on at first and then go out. The cooling fan continues to run. It never completes booting. From past experiences, this is usually a sign of not enough power being delivered but this regulator should deliver more than 10 amps. There is a USB SSD drive attached. As I understand the RPI 4 needs 4 amps to run. The RPI will boot when I plug in the regular wall wart. I have tried this with two different batteries and two separate regulators. Any ideas?

Hi, Doug.

Does the regulator work as expected with no load or other loads? What is the voltage on the regulator output when in the problematic state? (Looking at it with an oscilloscope would be best.) Does anything change if you remove all peripherals from the RPi?


Thanks Claire. This is my problem. There was enough wire and connections
between the RPI and the regulator to bring down the voltage just enough for the RPI to not boot. Cleaned that up and it works just fine. Appreciate the quick response.

The output voltage from the regulator should be same as the voltage required to power up the RPI and boot up correctly.