Pi not getting enough power

Hi guys, I am completely lost. All I want to do is have a pi powered by solar power. I’ve read the instructables and the forums, sometimes think I’ve got it and still same problem. I have a 6600 lipo as in guide, 3 solar panels from SwitchDoc, sunairplus2, and usb power controller 2. I plugged into sunairPlus2 from wall, till battery was charged, light was green. Have a lipo line from sunairplus2 to usb power control. When I flip the switch to (on)? The pi begins to turn on. But I get low Voltage warning and it just keeps rebooting until I kill power. Am I missing something really simple or is something not working. I have also plugged directly into sunairplus2 from usb skipping usb controller. Same problem. I Have tried grove female connectors from sunair to 3.3, gnd, scl, sda, and from power controller no change.