Solar Power Manager 5v - When does USB power activate?
James.McGill 2026-02-21 13:54:12 8706 Views3 Replies I picked up a Solar Power Manager 5v, plugged up the LiPo 3.7v and device to USB-A. Charging power is provided through micro-usb-in. It's been charging a few hours now but the USB-A device has yet to turn on. It works just fine with the same cable plugged into any other power supply, and turns on when I disconnect the battery.
Should the controller not be trickle-charging the battery while also powering the USB port? Is there maybe a charge threshold the LiPo needs to reach before the controller kicks on the USB power? It's a 8000mAh battery, so that just might take a long time.
Thanks for any help!
To protect the lipo battery, the USB OUT output will not be activated immediately when the Solar Power Manager is replaced or powered on. You need to press the BOOT button on the board to enable USB OUT output.
Yeez_B Hi, if the battery voltage drops below 2.4V, the output is cut off to prevent over-discharge.
Additional protection notes for reference:
1. Charging stops when battery voltage exceeds 4.3V (discharge still works)
2. Discharge path shuts off if discharge current exceeds 3A
Yx This behavior is actually normal for many Solar Power Manager 5V boards. They often don’t support true pass-through (charge + output at the same time), so the USB-A port may stay off while the battery is charging.
Some boards also require the LiPo to reach a minimum voltage threshold before enabling output, especially if it was deeply discharged.
If it powers your device when the battery is unplugged, that suggests the module prioritizes input power differently—check the datasheet, but most likely it’s a design limitation, not a fault.
parker.king 
Solar Power Manager 5V DFR0559