Solar Question

[slugbrain]

I’m trying to wire a 200W renogy solar panel to my goal zero yeti 1500x. The battery is about 16feet away from the panel. My camper is currently wired with 14awg and I am reading that I should use10awg wire for this but I’m wondering how bad it would be to use the preexisting wiring. Fire hazard or just poor performance? Thanks for the advice!

 

[Wandering Sagebrush]

Poor performance is certainly a concern with skinny wires.

 

[rubberlegs]

Isn't 14 gage good for 15 amps? Someone should check. 200W / 12V = 17A, so the wire sounds too small. Someone should check my numbers... these comments are seat-of-the-pants.

Solar panels, if there's no charger included, have a higher voltage, so you should check that value.

 

[Jon R]

The Renogy rigid 200 watt panel operates at about 19-20 volts when it is putting out max power, so the max current from the panel at best output is just over 10 amps. In fact, its short circuit current is only about 11 amps. If you have an mppt controller/charger, 14 awg should be just fine for one 200 watt panel. It would not be at risk for overheating the wire. The voltage drop won’t cause excessive loss at a 16 foot distance. Bigger wire would be better, though, from a loss reduction standpoint, especially if you have a PWM controller.

I have two of the Renogy 200 Watt rigid panels on my Grandby and I run them in parallel through the factory 10 awg wires from the roof connector to the battery compartment.

 

[Jack]

With a roof mounted solar panel, unless you are within the tropic of cancer and the tropic of Capricorn (within 23.4 degrees of the equator) on the right day, you won't get 200W. At the 45th parallel, you need to tilt your solar panel to 30 deg above the horizon at the summer solstice and to 60 deg above the horizon at the winter solstice to get full sun on the panel. Take your latitude and subtract 15 deg for summer and add 15 deg for winter for direct sun.

But if you have full sun, or at least a decent amount, your solar panel will output at around 20 volts, which means a max of 10 A. If you have very little sun, the panel will output around 13 V - but only an amp or two.

14 gauge wire is just fine for your 200 W panel.

 

[Dadocut]

Like others said, 14 gauge wire between the panels and the solar controller is fine. For 32' (you got to count the round trip) feet of wire you'll see about .084 ohms of resistance. For the ten amps or so your panels can produce you'll waste about 4.4% of the energy by heating up the wires. AWG 10 wire would only waste about 1.6% of the energy. Oh well, no big deal.

The problem to avoid is having a significant voltage drop between the solar controller and the batteries. My Hallmark camper put the solar controller a considerable distance from the battery. They mounted the controller in a portion of a roof attached cabinet and had about 40 feet of wire (roundtrip) to the battery. The result is the battery never charged to a high enough voltage and you don't get the full charge out of the battery. My solution was to move the solar controller near the battery and that solved the problem. this is particularly a problem with the modern LiFePO batteries. they have a very small voltage difference between fully charged and only partway charged. Any voltage drop between the controller and the battery means the battery won't be fully charged.

Have fun with it. I have two 100w Renogy rigid panels. The camper came with flexible panels that failed after a few years.