question

I believe the female on the MPPT (where the male from the PV would plug into is positive. To double check you can also do a continuity test on the negative, this is common to the battery negative connection

Hi Award.

I like Murray's -ve continuity check thing, and of course a polarity check on the wires from the pv too.

The trap for the unwary when describing MC4 connectors as male or female is that the plastic on the outside may appear one way, but is actually the other way round with the metal contactors within (as officially stated). I've scrounged up this link to hopefully indicate: https://www.solar-electric.com/learning-center/how-to-use-mc4-connectors-cables.html/

Given it's an 'Easy' box (as is mine), tis a little hard to describe which way around the /100 mppt is mounted, and then which is front or back. But if you look in the mppt's manual (in the Appendix at the very end), the internal contacts are actually shown if you look very closely. Those are the true male-female.

A little gripe from me. Why MC4 connectors anyway on the larger kit, which is invariably indoors and most likely downstream of an isolator/breaker? Then have to revert to waterproof MC4 to get in?

JohnC thank you for your response. I will take a look at the mppt’s manual but I agree why MC4. I also saw a response from Daniël Bokeel (Victron Energy Staff) MC4 for safety and finger easy but a simple diagram would certainly help. I will check out Murray van Graan’s suggestion and do a continuity check.