As there is no PD capability, have you configured the Pi5 to assume there is a 5A supply? There could be a problem that the UPS is not really a 5A UPS, when an incoming supply is present it can't provide 5A, in fact while the batteries are charging they do not specify what current it can provide, only when the batteries are full can it provide 4A. I presume when the batteries are discharging it can provide 5A so really it is not a 5A UPS.
The Pi5 should boot when power is applied unless the supply voltage doesn't rise fast enough.
The Pi5 should boot when power is applied unless the supply voltage doesn't rise fast enough.
Statistics: Posted by pidd — Mon Dec 22, 2025 4:32 am