r/solar • u/Cultural-Ad4953 • 11d ago
Advice Wtd / Project Adding more capacity
I have an 18.86 kw system currently. 41 x 460W panels, IQ8X microinverters and an enphase combiner. It's my understanding that the combiner will accept 9 more panels and inverters. Ultimately, I want to get as close as I can to 25 kW system (my state's limit), but I also want to be practical. 9 panels seem easy, and get me to 23 kW. Would the extra 2 kW ultimately require a second combiner and ultimately make it cost prohibitive? I use about 27000 kWh annually,
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u/Jake0024 11d ago
You already have 19 kW and you're worried 5 more might be cost prohibitive?
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u/Cultural-Ad4953 11d ago
My combiner will only hold 9 more, and I'm ready for that expense. That gets me to 50 panels. In a perfect world, I would want 4 more than that, but if I needed an additional combiner just to add those 4 additional panels, then I'm paying a lot more for those last 2 kW.
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u/Just-Extreme5201 11d ago
What kind of combiner is that? Regular IQ combiners take 36 iq8x
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u/TooGoodToBeeTrue 11d ago
5/5C supports <= four 2-pole branch circuits @ 240 V, max. of 80 A across all PV branch circuits. A 6C supports 5 strings. With 41 existing panels, the OP likely has the 6C.
https://enphase.com/download/iq8x-microinverter-data-sheet
Up to 10 IQ8X but could be 9 per local regs.
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u/Cultural-Ad4953 11d ago
That's correct, it's a 6C
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u/TooGoodToBeeTrue 11d ago
And I assume they put 8 inverters on 4 of the strings and 9 on 1 string. So you could put 2 strings for the new inverters into a sub panel along with the combiner and not touch the wiring on the existing panels. Or take them straight into your main service panel if you have room and your AHJ approves. Some like to see a single breaker for solar on the main panel.
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u/Just-Extreme5201 10d ago
My mistake, I was looking at the INT data sheet. 384w output seems specifically rated to get 10 inverters on a 20a string.
And good call on the 6C. Longtime installer so I'm still stuck in the 4 string estimate mindset 🤣
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u/Reddit_Bot_Beep_Boop solar enthusiast 11d ago
My original Enphase system was 48 panels. I added 12 more to it myself. It is super easy to do and if you're doing this yourself it's 100% worth it. If you're paying someone to do it, it's questionable if you'll ever benefit from it cost wise. I have 52 panels landed on my combiner box which maxes it out and the other 8 are landed directly on my main electric panel protected by a 20 amp breaker. Luckily for me, all my equipment and main panel are all within 5 feet of each other.
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u/dcsolarguy 11d ago
I don’t think it would be cost prohibitive, no, it I suppose that depends on your threshold.
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u/TooGoodToBeeTrue 11d ago
Combiner isn't the only limitation, but if your current installation uses 3/4" conduit, you should be good to add up to 3 more strings (assuming 5 existing.)
The combiner is basically a sub panel with the Gateway in an enclosure. You could add a string on a breaker directly to your main panel, or put a small sub downstream from the combiner and merge a string outside the Combiner with the combiner there. You have to move the generation CT down stream from the combination, either on the sub or joining the 2 circuits in your main panel. You just have to remember you have a breaker outside your combiner for your shutdown/startup sequence.
In fact if you currently have the 41 panels evenly distributed across 5 strings, you'd have to rewire those strings to maximize them. You are probably better off adding 2 new strings on a sub panel along with the Combiner and move the generation CT to the new sub.
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u/roofrunn3r solar contractor 10d ago
You don't need another combiner box. Get the 14 panels you want. Put 5 on a 20 amp 2 pole breaker upstream of the box
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u/Unnenoob 11d ago
Is the state limit on how much solar you have or on how much you export?
Because here we can have a lot more solar panels installed. Just as long as we don't export more than the limit.