I am just getting into Solar Panel hobbies and was not even aware of these type of connectors until I purchased my first solar panel. I watched a you tube video on how to terminate these and my first terminations went perfect. I love these connectors. I considered cutting off the connectors off of the wires coming from the solar panel but after ordering and using these, I am really glad I didn't do that. Once you use these I think you will agree that it is a good idea to use these instead of wire nuts or something else to preserve the integrity and warranty of the panel. A little bit pricy, but worth it because they are very nice. Also, I recommend to use just a tad of solder after you crimp the pin to the wire. It makes a rock solid connection.

These work ok, and will be fine if they are the only connectors you are using. Tried to connect to the existing connectors I had, but I had to modify them to work. The length of the male plug seems to be about half a mm too long, and that apparently matters. Otherwise, easy to use.

With competing listings going for nearly the same price for one pair, I found these to be a bargain. Until this point I had just been cutting off the MC4 connectors and using twist on wire connectors, and electric tape. Not very elegant, I know, but it just seem like such a waste to spend 20 bucks on every pair of cables. Now that the prices have become reasonable I've purchased several of these in order to upgrade all of the connections to MC4.

I found these connectors to be flawless. They're operated perfectly under heavy load. I recommend to anyone wants to put them under heavy load that they use solder after crimping in the space between the crimping area and the hollow area also I would extend the copper wire all through the hollow area so that there's plenty of contact. These are great for the price I'm glad there is a seller offering them at such a reasonable price they seem to be very high-quality. Please note you must put on the pieces onto the wire in sequence, you have to put the round nut onto the wire then the compression nut then crimp the wire then, if you were me you'd solder in the space between the crimp and the enclosed hollow area that you should've filled with copper wire, careful not to overflow or make the connector more wide, then close it all up. It's not really easy to pull the the internal male and female pins out of the connector once they've been locked in place, without damaging the connector. So make sure you have that washer the compression nut with the little cuts facing down towards the wire (away from the pin)nand everything is in order before you push the pin in, and then screw the nut on tight.

Before I could even complete that project though, the batteries that I had using for years, finally hit end-of-life. As soon as I realized this I ordered a replacement on Amazon from a third-party seller, which turned out to be defective. As you can probably see from my reviews I depends on solar power I purchase all of these items to be used with my solar array.

In the interest of other people assembling solar arrays or servicing them, The reply that I got from one of the Escalated CSR agents at Amazon On Friday, March 15, 2013:

"I don't mean to sound cold, but you chose to live off of batteries. That's not Bluegrass Wholesale's problem, and that's not Amazon's problem." Customer centric? Earth friendly? It sure doesn't feel that way! There's nothing wrong with living off solar and batteries, there is something wrong with cheating a customer and doing absolutely nothing proactively to make it right, at least one of the CSR agents was able to provide a 12 amp hour motorcycle battery so that I wouldn't be in pitch black darkness.

Nonetheless, although this particular product seems to work just fine, I'd be cautious making purchases for your solar array on Amazon, since they seem to have customer service representatives that consider off grid living some kind of deviant lifestyle. And should you need an A-Z claim they have absolutely no idea what any of this stuff is for or how it works.

I got these not knowing what size wire I would use or what crimper to use. They appear to be designed to make a waterproof connection, assuming the wire is thick enough. I think it needs 14AWG minimum or the seal may not clamp well on the wire (probably 10AWG max). You can figure out which connector gets which pin by seeing which one won't fit into the end of the pointy connector. Panels will (usually) be positive on the pointy connector. So you connect your positive wire to the non-pointy connector since that's what the panel's positive terminal would connect to. (I was dumb enough to get this backward the first time.) I crimped using some electrical tools at work. If you don't have access to such tools, you should buy the correct crimper or you're guaranteed to have a bad connection.

All the items I bought to place a solar system on the ski pod of our van have worked well through a summer and winter. If I were going to do another installation of a similar nature, I'd go once again with the same parts. It seems worth it to spend the extra on a mono-crystalline system with the better and higher capacity controller. I did buy the computer interface cable from China and tried it. The cable seemed faulty and the software looked primitive, so did not end up using that option, the remote meter seems to be enough.