I used to think there was something like a standard color code, but then I learned that trailers were different. Then I bought stuff from Amazon (no instructions) and learned that the UK, Europe (IEC) and China also have unique codes, and they are different.

(BTW, the reason ABYC does not use Black for the 12 V negative is to avoid confusion with the 120 V hot. My boat doesn't have a 120 V system, so I'm not worried. The IEC also specifies a different color for the high voltage neutral (blue).

You can pay $500-700 for a name brand panel. No doubt they are very good and 4 different middle men took a cut to get it there. You can go on the internet and get something on E-Bay that might... or might not work. When I installed my system I went on the net, took a good close look at the images and specs, read a few user blog post, and picked out panels that were solid and are still working well. But I've heard stories of the other sort.

Hotwire is a guy that started investigating solar and wind for hi own use 20 years ago, tried everything, tested samples, and has made a solid little name for himself among cruisers as a guy that sells right-priced stuff that he has tested and vetted himself.

But it's a lot more than that. Wind, charge controllers, mounts, lighting, refrigeration... all with an eye towards economy and reliability.

Check it out.