Ok this might be a stupid question but I am doing a 5S4P ground mount system with 2x 5Kw Growatt inverters. I watched Wills video on combiner boxes but I was confused on one thing. All the combiner boxes I saw seemed to combine all connections down into 2 wires 1 + and 1-. So how does that work if you are doing 2 inverters? If I was to connect into 1 inverter it would be too many volts. I went with 2 inverters because that's what the company I bought my order from recommended. I was originally going to do a single 10KW inverter but they said 2 5kw inverters would be better (didn't really understand why). Do I need 2 combiner boxes? Am I over complicating things? I also bought a DC disconnect switch but now after seeing these combiner boxes I am thinking I probably don't need both.
Combiner box with 2 inverters. How to?
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MisterSandals
Participation Medalist
This cannot be done. You would need to run 5S2P into each MPPT.
That was basically my question. I was planning on doing 5S2P into each inverter but does each of those go into 1 combiner box or do I do 2 separate ones or do I even need a combiner box for this scenario?
MisterSandals
Participation Medalist
A single combiner box presumably combines all the input into one output. So you would need 2x combiner solutions.
What kind of amps are you talking about where a simple Y connector won't work?
These are good for 30A normally:
MisterSandals
Participation Medalist
Just get some that handle the amps and volts.
Voltage& Current: 1000V, 40 Amps
SolarHead
50% of people are below average. (Its a statistic)
I like combiner boxes, because you can put breakers , or what I have been told fuse holders , which are better than breakers. I dont know much about GroWatts, but if they are transformerless like the Sol-Ark, then you have to wire the combiner boxes using a configuration that does NOT ground the PV wires. If you want/need more info on that, find a MidNite Solar brand combiner box online, look for the PDF instructions and in there it should show how to wire for a transformerless inverter.
On the note of you buying 2 inverters instead of one, again I dont know much about GroWatts, but will one of them do 120/240 or are you having to get 120v from each inverter in order to have 240v? Maybe thats why they are recommending 2 inverters, I dont know.
Usually I dont see 5S2P, usually its even numbers like 4 strings of 9 panels (for example). Usually the strings are an even number, not odd. But the numbers of panels can be odd number. I'm sure theres 1000 ways to configure panels wiring but main thing is, you get most strings you can so shading isnt as much of an issue, and you stay within the MIN/MAX voltage rating that the inverters MPPT's require. Then your amps on each string, get a fuse holder. I would not skimp on combiner boxes to be candid about it. MidNite Solar makes a ton of them and usually you can find the exact model you want. The Y connectors, I dont tend to use them if at all possible. If you're doing a few panels, or say on top of a RV, sure. My 2 cents of course. I think you'd end up with a better job using combiner boxes.
On the note of you buying 2 inverters instead of one, again I dont know much about GroWatts, but will one of them do 120/240 or are you having to get 120v from each inverter in order to have 240v? Maybe thats why they are recommending 2 inverters, I dont know.
Usually I dont see 5S2P, usually its even numbers like 4 strings of 9 panels (for example). Usually the strings are an even number, not odd. But the numbers of panels can be odd number. I'm sure theres 1000 ways to configure panels wiring but main thing is, you get most strings you can so shading isnt as much of an issue, and you stay within the MIN/MAX voltage rating that the inverters MPPT's require. Then your amps on each string, get a fuse holder. I would not skimp on combiner boxes to be candid about it. MidNite Solar makes a ton of them and usually you can find the exact model you want. The Y connectors, I dont tend to use them if at all possible. If you're doing a few panels, or say on top of a RV, sure. My 2 cents of course. I think you'd end up with a better job using combiner boxes.
MisterSandals
Participation Medalist
Huh? He has 4 strings. He wants to combine them into 2 strings.
SolarHead
50% of people are below average. (Its a statistic)
IMHO you're going to want to use combiner boxes, and DC disconnects so you can cut power off from the array.
Make sure the voltage/amperage works for your situation, this is what I used
thepowerstore.com
Scroll down to page 7 where it says "Transformerless Configuration". If your Growatts are not transformerless like the Sol-Ark, then look to see if they have another wiring diagram for your application
I can't tell you exactly what to do, but I can point you in a direction that you can hopefully find a solution.
Make sure the voltage/amperage works for your situation, this is what I used
PowerStore | Wholesale Solar Inverters, Grid-Tied Solar
PowerStore provides a one-stop shop for wholesale solar products, including grid-tied solar, off-grid solar, and solar storage solutions. Same-day shipping. Shop now!
thepowerstore.com
Scroll down to page 7 where it says "Transformerless Configuration". If your Growatts are not transformerless like the Sol-Ark, then look to see if they have another wiring diagram for your application
I can't tell you exactly what to do, but I can point you in a direction that you can hopefully find a solution.
SolarHead
50% of people are below average. (Its a statistic)
he mentioned 5 strings I think/thought/thunk
SolarHead
50% of people are below average. (Its a statistic)
Maybe its the root beer talking. He mentioned 5S2P
I guess that means 5 panels in series, and 2 parallel. Would that be 10 panels total ?
I guess that means 5 panels in series, and 2 parallel. Would that be 10 panels total ?
So basically I have 20 panels with the above configuration and based on my area (not much width to place them) I have to do a mount of 5 across and 4 high. So for ease of wiring I figured I would do 5S4P but split the parallels into 5S2P.
BTW I think you are correct that to achieve 240V they suggested to go with 2 inverters. I don't have any appliances that use 240V currently but they wanted me to plan for the future...also I mentioned that I might do an EV vehicle down the road which If I remember made them lean towards the 2 inverters as well.
BTW I think you are correct that to achieve 240V they suggested to go with 2 inverters. I don't have any appliances that use 240V currently but they wanted me to plan for the future...also I mentioned that I might do an EV vehicle down the road which If I remember made them lean towards the 2 inverters as well.
yes 5 panels in series and 2 in parallel for each inverter. So 5S2P to each inverter.
MisterSandals
Participation Medalist
DC disconnects are a no-brainer. But a full combiner box for 2x 11A strings is overkill.
He has 5S4P but 2x MPPTs. So running 2P into each MPPT is the easy way. Combining 2x ~11A strings with a simple Y connector is more than sufficient.
I bought this one.IMHO you're going to want to use combiner boxes, and DC disconnects so you can cut power off from the array.
Make sure the voltage/amperage works for your situation, this is what I used
PowerStore | Wholesale Solar Inverters, Grid-Tied Solar
PowerStore provides a one-stop shop for wholesale solar products, including grid-tied solar, off-grid solar, and solar storage solutions. Same-day shipping. Shop now!
Scroll down to page 7 where it says "Transformerless Configuration". If your Growatts are not transformerless like the Sol-Ark, then look to see if they have another wiring diagram for your application
I can't tell you exactly what to do, but I can point you in a direction that you can hopefully find a solution.
IMO DC Disconnect Rooftop Isolator Switch
IEC 60364-7-712, dc disconnect, imo, ul listed, DC AC, DC DISC
signaturesolar.com
I will check and see if they are transformerless.IMHO you're going to want to use combiner boxes, and DC disconnects so you can cut power off from the array.
Make sure the voltage/amperage works for your situation, this is what I used
PowerStore | Wholesale Solar Inverters, Grid-Tied Solar
PowerStore provides a one-stop shop for wholesale solar products, including grid-tied solar, off-grid solar, and solar storage solutions. Same-day shipping. Shop now!
Scroll down to page 7 where it says "Transformerless Configuration". If your Growatts are not transformerless like the Sol-Ark, then look to see if they have another wiring diagram for your application
I can't tell you exactly what to do, but I can point you in a direction that you can hopefully find a solution.
SolarHead
50% of people are below average. (Its a statistic)
I agree, he could get it done that way. I built my system with overkill where I could easily expand in the future. I've seen so many solar videos where the guy is installing and he's on his 3rd or 4th expansion.
MisterSandals
Participation Medalist
That will work. So you'll be cutting + and - of both strings if installed after the Y connectors?
Or cutting + only if installed before the Y connectors? (you will have 4x + and 4x - before the Y connectors)
SolarHead
50% of people are below average. (Its a statistic)
If/when not using combiner boxes, would you recommend using in-line fuses with MC4 connectors ?
MisterSandals
Participation Medalist
I think he is at the limit of his SCC so not sure what the expansion would be. Besides, he'll be in for $15 for each pair of Y connectors. Whereas combiner boxes are $80-100 (but have fuses and breakers so no need for a cutoff... they're pretty deluxe most of the time).
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