Testing Power Banks for Raspberry Pi with Solar Charge

I quickly test four different power banks of varying capacity to measure output voltage under no load and 1 Amp load conditions. I also look at happens when a charger is plugged in to the power bank to test power pass through capability. I cannot guarantee that the voltmeter is acurate and all of my meters give slightly different readings since I have no standard voltage source. These power banks are designed for charging consumer devices like mobile phones and not for supplying continuous power to remote equipment, possibly with solar charging, so they have an excuse not to perform as perfectly as I would like. The power banks tested were: INIU Bl-B63 Anker 737 VEEKTOMX VT103 Jackery 100A