Not long ago I bought an Anker power station, a C2000. It's basically a 2.5 gallon bucket full of electricity. 2 kilowatt hour battery, a fairly beefy inverter that can put out 22A continuous and peaks at something like 33A so it can both run AND start my table saw.

It also has a solar power input, A DC jack on the side, with I believe an MPPT charger built-in. It came with a big weird flexible solar panel that is allegedly rated for 200 watts, I barely ever saw 80. I think it's built the same way as like a backpack solar panel, but it's 2 feet tall and 6 feet wide. Difficult to deal with.

Went to Harbor Freight, picked up a pair of 100 watt panels there. $119 each. More typical glass with aluminum frame rigid panel. These are working considerably better. The one thing: The panels have Anderson Powerpole connectors, I had to buy a separate cable set, and the Anderson to MC4 connector cable I bought at Harbor Freight is backwards. I guess it's designed to be a load-end and not a source-end cable?

I had to pull the Geordi Maneuver: Reverse the polarity.

What I did is cursed. I know it's cursed. On the adapter cables, I de-pinned the Anderson Powerpoles and swapped them left for right. So a red wire is going into a black connector. The color coding on the cable is backwards. You know that movie Defending Your Life, with Rip Torn? When I die and go to Judgement City, they're going to ask me about this. But it works.

With the voltage you’re running I don’t think it’s a concern.

Gross and uncomfortable though, I agree.

Throw some black and red electrical on each end to make it the correct color. Or use green tape if you really wana curse your wiring

The copper is perfectly fine. It's just the color of the jackets. For a good 50cm, + is black and - is red. It's bad juju. What's the proper hoodoo for warding off the juju from incorrectly color coded power cables? Burning lavender? Changing the batteries in your smoke detectors?

I can confirm the Anker has reverse polarity protection on the DC input. It just didn't do anything when I plugged a panel in wrong by trying the connectors as-is out of the box. It didn't even bitch at me.

I could buy or make the right adapters, or snip the powerpoles off of the panel wires and install the correct MC4 connectors, and then have fewer connectors in the system.

My father owned a Lotus, several, they came with random battery cables either both black or both red.

It's a 100W solar panel at 27V. I don't think it's going to blow up in your face.

Might let some smoke out of a fairly expensive battery bank if wired incorrectly though.

True. If I have to use black cable on positive leads I just put some red shrinkwrap on the positive end of the lead. I usually do black on the negative just to be consistent.