I have five strings, each 48V, at about 200ft away from my residence, and I'd like to combine them near the panels (mounted on a fence post). The panels are spread out, with the wires running underground via a conduit. I'm in search of a weatherproof combiner box that can be located near the panels and accept both input / output from PVC electrical conduits (either 1" or 3/4"). Most of the PV combiner boxes I've come across use either MC4 connectors or cable glands, but I need a solution that accommodates PVC conduits. Could anyone point me in the right direction or recommend a product suitable for this purpose?
Outdoor PV Combiner Box
- Thread starter vicmel
- Start date
Zwy
Solar Wizard
A combiner box like this: https://watts247.com/product/6-2-solar-panel-combiner-box-3-into-1-twice-63a-max-output/ you simply remove the glands and run conduit it's place. Extra holes you can use a blockoff.
MichaelK
Solar Wizard
This is what I use. It has conduit knockouts on the bottom. BTW, 48V is a rather low voltage to be running for a distance of 200 feet. May I ask why that is? I'm running my solar panels at 120VDC. What is the brand/limit of your controller?
Oh, I didn't realize that 200' is considered far. Thanks for pointing that out. Here's my current plan:
I have twenty 12V, 100W panels mounted on a custom trellis overhang, which provides shade to my vegetable garden plants. These trellises are spread out along the rock wall in my backyard. My idea is to connect four panels in one string (48V) and run those lines to the string closest to the house. The farthest string will have about a 100' run, and that's where I plan to place an outdoor combiner box.
From there, I'd run a single cable for about 100' to the inside of the house, near the garage, where I intend to mount an All-In-One unit for charging a battery. I plan to use this battery to power all my outdoor lighting at night, garden sensors, Christmas lighting, etc. If possible, I would also like to run my small garage ac unit 120V also.
Any suggestions from you all would be greatly appreciated. Thank you.
I have twenty 12V, 100W panels mounted on a custom trellis overhang, which provides shade to my vegetable garden plants. These trellises are spread out along the rock wall in my backyard. My idea is to connect four panels in one string (48V) and run those lines to the string closest to the house. The farthest string will have about a 100' run, and that's where I plan to place an outdoor combiner box.
From there, I'd run a single cable for about 100' to the inside of the house, near the garage, where I intend to mount an All-In-One unit for charging a battery. I plan to use this battery to power all my outdoor lighting at night, garden sensors, Christmas lighting, etc. If possible, I would also like to run my small garage ac unit 120V also.
Any suggestions from you all would be greatly appreciated. Thank you.
Attachments
OffGridInTheCity
Solar Wizard
And these Midnite Combiner boxes have an option for a 'Red Handle' quick disconnect on outside of the cover - it pulls down (or up) all 1...6 breakers in one swoop. These are ETL/UL.
Here's an example source - https://www.altestore.com/store/enc...ite-solar-mnpv6-disconnectcombiner-box-p9714/ There may be cheaper listing with a little searching.
MichaelK
Solar Wizard
OK, you are making some mistakes here. Very most likely, your four 100W panels will NOT be putting out 48V. It's called a 12V panel because it's used in 12V applications, NOT because it's output is 12V. You also pay a price premium for going with panels designed for automotive use. You would have gotten more W/$ if you had instead purchased larger high-voltage residential grid-tie style panels.
Flip a panel over and look at the nameplate on the back. You will see values for Vmp, Voc, Imp, Isc. Please refer to those as your operating values. Most likely, one panel will have a Vmp of ~18V, and a Voc of ~22V. These numbers are VERY important in the proper design of your system. The Voc is what you pay attention to when you are deciding what size string to feed into your controller. Don't decide on how many panels you put in a string until you know the specifications of your electronics. Some controllers have voltage limits down at 100V. Some are 450-500V. You have to know first what you are working with. Controllers also have minimum voltage requirements, below which they don't work properly. You need to do more research here.
BTW, four panels in series might have a Voc of 88V, but that's at room temperature. As the panels get colder, their voltage goes up. That 88Voc, will likely bump up past 100V slightly below freezing. So, the first frosty morning will fry a 100V limit controller.
The good news though is that the voltage drop for four panels in series is not as bad as I expected. Assuming each panel is 18V, so four is 72V. Here's a voltage drop calculation to show how much power you are losing at 100'. Not too bad.
You can play with this drop calculator yourself, as you gain more details about your proposed system.
Voltage Drop Calculator
This free voltage drop calculator estimates the voltage drop of an electrical circuit based on the wire size, distance, and anticipated load current.
www.calculator.net
