I’m trying to create a battery-powered RPi 3B+ system and am running into issues almost immediately due to the Pi’s power requirements. I’m testing using a 5V 3A wall power supply which is running into the official 7” Touchscreen, and from that to the Pi via the GPIO 5V pins. That seems to be working as long as I only use a mouse and keyboard, but if I plug in any other USB devices, such as an SSD, I start getting low power warnings. Trying to power it via a Nitecore 10000 mAh Powerbank rated to 5V 3A I get immediate low power warnings with only the screen connected and no other peripherals at all!
I admit I’m a neophyte when it comes to electronics, but I can do basic addition and I’m not running anywhere close to 3A of power draw with only the screen and RPi connected and idle.
One solution I’ve seen is to use a DC to DC buck converter, but how can I be sure that whatever I get will maintain the 5V above 2A? Seems like many of them drop low enough to cause problems as soon as there’s any load. It doesn’t help anything that the Pi seems to want 5.1V instead of 5.
Thanks for your help. I apologize in advance if these are basic questions, but I’ve researched it quite a bit and finding many people complaining about this but no verified solutions offered other than wall power. I’ll throw a car battery in there if I have to, but what needs to go in between?