Using Two Harbor Freight Solar Panels in Parallel with Wiring of an Appropriate Gauge

In a video I made a few months ago I talked about using two 100-watt Harbor Freight solar panels to provide power to an Anker PowerHouse 535 Power Station (sometimes called a solar generator). I was pleased to find that I could use the two panels together with a parallel electrical connection, which made it possible to sustain a 100-watt input into the solar generator even when the panels weren't providing their maximum output (due to clouds or just generally non-optimal positioning relative to the sunshine). This practice of using solar panels which can provide more wattage than the input can use is sometimes referred to as “over paneling”. However, I eventually purchased an Anker 555 device which can accept 200 watts of electricity for charging. When I used both solar panels under optimal conditions then the input of the Anker 555 was taking in 200 watts at somewhere between 12 and 20 volts. I noticed that the the wiring which was carrying that load between the panels and the solar generator was getting hot. Obviously, it was not designed to carry such a big load.

What went wrong? The fact is that there's a relationship between volts, amps and watts. 200 watts at 120 volts would be about 1.67 amps. But 200 watts at 12 volts is about 16.67 amps and THAT was too much for the wires I was using.

My solution to the problem of overloading the wires was to replace most of the wires with heavier-duty wiring. First off, I used an adapter on each Harbor Freight Solar Panel to go from their default SAE connectors to MC4 connectors which are more commonly used in solar panel installations. Then I used an adapter to go from MC4 connectors to the 8mm "barrel" connectors which fit the inputs on my Anker solar generators. Problem solved! The thicker wires are completely up to the task of carrying more amps than the previous wires I was using. This also allowed me to easily utilize a heavy-duty extension wire with MC4 connectors, and now my solar panels can be 30 feet farther away from the solar generators (which can stay protected from harsh sunshine or rain).

If you are setting up solar panels for a portable power station it is essential that you match the voltage of the panels with the power station’s acceptable voltage range. In my case, the Anker solar generators can accept 12-28 volts and these Harbor Freight panels are within that range. If I had connected two panels in series then the voltage would be too high. But when they are connected in parallel they’re just fine. Another essential concern as you’re setting up connectors and adapters is polarity. A simple, inexpensive multimeter will tell you if your DC power connector is providing the correct polarity and many SAE cables come with adapters to reverse the polarity if necessary. If you connect power in the wrong polarity it may cause your power station device to simply not respond OR it may actually damage the device. I don’t know what my Anker devices would do with reverse polarity power. I’ve never connected power to them incorrectly and I am unwilling to test that on my own gear.

In this video I'm trying to use specific panels with specific Anker devices. But the same concerns apply when you're using solar generators from other brands like Jackery, Goal Zero, EcoFlow, UGreen, Bluetti, Renogy and many, many others. And if you happen to buy other rigid-frame solar panels which are similar to these Harbor Freight "Thunderbolt" panels (such as panels from Renogy, Newpowa, BougeRV, and others) they will probably already come with MC4 connectors... but they probably won't have the built-in "kick stands" that I like with the Harbor Freight panels. Bottom line: There are lots and lots of options from many companies. If you plan to mix-and-match panels and devices then make sure you have the right connectors (or adapters for making them right), the right voltage, the right polarity and the appropriate wiring to carry all of that electricity. Good luck!