External DC Power

[Old Hippie]

I am an e-bicycle tourist who does not have access to AC often enough to keep my L390 charged. I configured a DC to DC converter to go from my 48 V e-bike battery to 20 V for the USB-C. When I power it on, it does not charge, it does nothing. Why?

[axur-delmeria]

Are you just connecting the positive and ground wires to the USB-C connector? That's not gonna work, because the USB-C power delivery protocol requires the power source and device to "talk" to each other to figure out the voltages the source can put out (+5v, 9v, 12v, 15v, 20v etc.) and which voltages the device can accept. You could get something like this slim tip to USB-C power adapter and connect your DC-DC converter's 20V output to the slim tip input.