Adding an Mc4 extension cable

[Willowflowage]

I have two 100 watt Poly panels with 30 feet of 12 gauge Mp4 cable going to a PWM controller. I use these on the ground for better Sun.
At times longer cables would be helpful. Any thoughts on adding 10 or 20 foot extensions?
If so 10 gauge isn't much more $ than 12 so would it make any difference with ten gauge on the end connecting to the 12 gauge at the panel? Or is the whole idea stupid?

 

[Lou Schneider]

Shouldn't be a problem. 25 ft. orange (or green) extension cords are a handy source of wire nicely packaged in a weatherproof jacket. Look on the jacket to see what gauge wire is inside. You can even double up the green and white wires to further reduce the voltage drop by an additional 1/3. Just cut off the ends and splice on your MC4 connectors.

All you need is to make sure your panels have enough voltage to compensate for the wire loss. 12 amps through 25 ft. of 12 gauge wire will lose slightly less than 1 volt. 25 ft. of 14 gauge wire will lose about 1.5 volts. With a PWM controller the panels almost certainly have enough surplus voltage to compensate for this with little or no loss of performance. If you had a MPPT controller you would lose about 10% of the MPP power.

 

[Willowflowage]

Playing with panels through through the West Windows in the house my frozen low angle sun and panels put out over 18v so I think I'll be good with an extension for camping. 30 ft extension coming Monday so I'll do some testing outside.

 

[Willowflowage]

I have since used an obsolete orange extention cord that I put mc4 plugs on, about 40 ft that works great!

 

[Mark_K5LXP]

I made up a set of short adapters with a DC connector at one end and 15 amp plug and socket on the other, with the idea I could use any extension cord(s) I needed to get between A & B. Yes, this has a hazard of accidentally plugging something into an AC socket that shouldn't be but in practice that hasn't been a problem. Being able to mix and match any available extension cords based on length and gauge needed is a handy thing.

Mark B.
Albuquerque, NM

 

[Lou Schneider]

I made up a set of short adapters with a DC connector at one end and 15 amp plug and socket on the other, with the idea I could use any extension cord(s) I needed to get between A & B. Yes, this has a hazard of accidentally plugging something into an AC socket that shouldn't be but in practice that hasn't been a problem. Being able to mix and match any available extension cords based on length and gauge needed is a handy thing.

Mark B.
Albuquerque, NM

Using Neutral and Ground as the active conductors and leaving the hot pin unused will reduce the chance of damage if the device is accidentally plugged into an AC outlet.

 

[Mark_K5LXP]

Works out that anyplace I've used them there's no AC power around anyway but good idea, and easy enough to do.

Mark B.
Albuquerque, NM