Battery hookup

If you have the solar port on the propane tub, you should have a red and white cable extending from that port to the inside of the tub.  The red is positive and the white is negative.  The blue cable probably holds a plastic fuse box and the cable may be spliced into a red cable - that goes to the positive terminal of the battery.  The other white cable goes on the negative terminal of the battery.  Here is a picture of mine.  Ignore the thin, red cable as it supplies the charge to an optional battery monitor.  Make sure you put the negative cable on last.