My project is to take solar power from a 6w/6v panel, run it through a buck circuit tuned to 5v and charge one of the LiPo power banks. I perceive a buck circuit would do better at efficiency than a power regulator, though I could be wrong.
However, the power bank does not respond at all to the input. I've troubleshot the connectors, voltage all the way through up to the usb micro b male connector. You would be right to ask how can I be sure the micro plug is not the cause? When I hook this to a cell phone, it appears to be charging. (it may not be actually charging but at least it is receiving voltage).
Reading around on Google, I've tried tying the data wires together to short it out, and test it against known-good. In reading, the outer pins are for voltage but current is tied to the device. Since the power bank is not responding, current measurements are not shown but powering the cell phone shows 2.61 on the 20 scale. That's not a reasonable validation but this is to show that the current measurement does work.
So, what am I not understanding about the usb power requirements in reference to charging this device? thx, sam