Confusing polarity display. For thejackery entry, the outer shell is NEGATIVE. The inner sleeve is POSITIVE. The center pin is not used. It's strangely connected. cheap enough so i just cut off the mc4 connectors and plug them straight into the panel. RED TO RED AND BLACK TO BLACK. This worked for my needs, but you should check your cable with a meter for continuity, where each pin goes to the connector, and for your application. Again. to enter Jackery. The inner sleeve should be connected toβ¦