Portable solar from 2 regular size panels

[opie]

Is 10 gauge wire the largest the mc4 connectors will accept? Id like the ability to stretch the panels out as needed, probably no more than 30 feet and I have plenty of 4 gauge cable left.

[Briorick]

While reading some reviews on Amazon 1 reviewer noted that he was able to use 6 gauge on his connectors with no fitting problems to his mc4 connectors. He noted that this too was the largest gauge the mc4 connector sleeve would accept.

[opie]

Alright. Thanks.

Sent from a field

[mnoland30]

Voltage Drop Calculator

This is a great calculator for voltage drop. 200 watts at 12 volts is 16.7 amps. The panel puts out 18v or more, but I don't know if you correct for that. If so, it is 11.1 amps. I've been told you don't want more than 3% voltage drop between the panel and the charge control. That means big wires if you want 40 feet.

I glued my flexible panel to the roof with silicone. No screws. No issues.

Don't worry about the sleeves on your connectors. Get the right size wires and use lugs from Home Depot to adapt to the wire size.

[larryandamy]

Renogy rates to MC4 connectors for only up to 10 AWG. See Renogy answer to this question below:
"These MC4 connectors accept 12 and 10 AWG wires.
Regards,
AW see less
By Renogy Solar on April 29, 2015"

You could never fit a 4 or 6 AWG in an MC4 and if you did with soldering, the connector itself is only rated at 30 amps.
I use the Renogy 30 charger and it will only accept 10 AWG max in the panel input connectors.
I always crimp and solder the wires into the connectors to minimize voltage drop. for 20' length 10 AWG is great. for 30' I recommend 8 AWG and for 40' you should use 6 AWG. You could get by with 8 AWG at 40' with no reliability issues and an insignificant loss of charging voltage.
You need to use high current connectors as interim connection point to join the panels 10 AWG wires into the long run to the charger. I used 350 amp connectors that allowed me to join multiple 10 AWG cables on one side and run up to 2-4 AWG on the other side. See link to this connector below:
Amazon.com: 2-4 Gauge Driver Battery Quick Connect Plug Kit Recovery Winch Trailer 350 amps: Automotive
This worked great for me and the voltage drop at 200W fully charging at ~12 amps was <0.010 VDC across the connector.
You do drop voltage in the longer wire lengths, but the crimps and connectors usually have the largest share contribution to voltage drops.
So always crimp and solder the cables into the connector pins and use high current connectors like above. This also gives you easy disconnect points for panels to cable to charger to batteries making set up and storing much easier.