It's been a few years since I installed a PV system. I'm old school. I've sold hundreds of PV systems, but almost all of them were in the early 90s. I'm used to seeing a nice junction box with knockouts on the back of a PV panel.
Recently I was asked to go to Haiti to install a PV system in a remote village that has no power. It would provide lighting and cellphone recharging for a small community. I jumped at the opportunity to help people in need.
I just got back. Everything went OK but I have to rant a little bit about MC4 connectors. THEY SUCK! I can see they would be nice if I had to string a bunch of panels together in series. But don't you think if a panel is 55 watts and 12 Volts that there's a good chance that the user would want to wire them in parallel?
not only are the fancy connectors on the end USELESS to me because the male-female paring is only set up for series connections, but the junction boxes are also useless. The MC4 wires are soldered in there with no way for me to remove them without a soldering iron. Anyone got a soldering iron at 5,000 feet up in the mountains of Haiti? And even if I could remove them there's no convenient way to bring in my own wire - no terminal strip -- all I can do is cut the ends off the MC4 wires and figure out some way to make it not look completely ugly. I ended up having to make some connections outside of conduit with splitbolts -- the only thing I had to get the job done, and it looked like ****.
don't they know that parallel connections require TWO wires coming in to each terminal?
you're probably wondering what modules I was using:
note they are listed in their "off grid" section.
someone should design a universal connector so you can make parallel and series connections with the same ends. But even then, you still need to bring two wires in to each terminal ON THE MODULE when you're making parallel connections, so we need a terminal strip. If you're going to put those useless MC4 things in there, at least make a convenient way for us to remove them and bring in our own wires.
Anything that is 100 watts or less and 12V nominal should not have MC4 connectors on it. Just give us a junction box, knockouts, and terminal blocks.
OK, I'm going to complain to the manufacturer now. Thanks for listening. Have a nice day.
Recently I was asked to go to Haiti to install a PV system in a remote village that has no power. It would provide lighting and cellphone recharging for a small community. I jumped at the opportunity to help people in need.
I just got back. Everything went OK but I have to rant a little bit about MC4 connectors. THEY SUCK! I can see they would be nice if I had to string a bunch of panels together in series. But don't you think if a panel is 55 watts and 12 Volts that there's a good chance that the user would want to wire them in parallel?
not only are the fancy connectors on the end USELESS to me because the male-female paring is only set up for series connections, but the junction boxes are also useless. The MC4 wires are soldered in there with no way for me to remove them without a soldering iron. Anyone got a soldering iron at 5,000 feet up in the mountains of Haiti? And even if I could remove them there's no convenient way to bring in my own wire - no terminal strip -- all I can do is cut the ends off the MC4 wires and figure out some way to make it not look completely ugly. I ended up having to make some connections outside of conduit with splitbolts -- the only thing I had to get the job done, and it looked like ****.
don't they know that parallel connections require TWO wires coming in to each terminal?
you're probably wondering what modules I was using:
note they are listed in their "off grid" section.
someone should design a universal connector so you can make parallel and series connections with the same ends. But even then, you still need to bring two wires in to each terminal ON THE MODULE when you're making parallel connections, so we need a terminal strip. If you're going to put those useless MC4 things in there, at least make a convenient way for us to remove them and bring in our own wires.
Anything that is 100 watts or less and 12V nominal should not have MC4 connectors on it. Just give us a junction box, knockouts, and terminal blocks.
OK, I'm going to complain to the manufacturer now. Thanks for listening. Have a nice day.
I can see that it would have been more manageable if the manufacturer had made this obvious in their specs and you had been able to plan for it before going on site!
Except for cost, making up an elaborate wiring harness in advance with all of the MC4 connectors on it make the parallel array hookup would have looked better, but still been impossible to expand unless it was also designed for that. The cost of two MC4s on each terminal of the panel from the manufacturer would not make a lot of sense, and a terminal strip instead of soldering would make the panel assembly less reliable. Maybe an option from the manufacturer to mount a connector box with terminal strip instead of the MC4s? But then both versions might have to go through all of the approvals separately.
I don't see a good solution other then information.
PS: Apparently the cheapest way for most people to get assembled MC4 connectors to use for harnessing is to buy MC4 extension cables and cut them in half.
PPS: I'm sorry, that would just make too much sense.
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