Hey everyone - I have questions!
Basic background info:
- Building a large cabin in the woods
- Designing for being fully off-grid year-round
- Will install a large backup propane generator as a just-in-case (pays to be prepared)
- Solar panels will be ground-mounted
- Prefer the solar panels be as far as science allows from the house
I'm trying to design a system that operates year-round without needing to pull from a generator, but it's OK if it needs a few days here and there.
Note: I have already planned out my power usage using the spreadsheet provided by this forum, thank you!
I am trying to pick equipment to use. I was thinking a 48v system with:
* 2 pallets of these Hyundai 390w panels, planning to use 48 panels for a max peak of 18,720w
* 57.6 kWh of these LifePower4 batteries in 2 separate server-racks
-- this should be ~2 days of full backup power, assuming 48 hours of zero solar production
edit:I'm getting a bit hung up on which inverter(s) to use. There a growatt 12kw split-phase off-grid inverter that seems great, but I would need 2 of these, plus the max PV power on the spec sheet says 7,000w. Doesn't this mean that with 2 of them, it could only do a total of 14,000w incoming from the panels, which wouldn't be enough to charge the batteries and power the house during the winter?
So, the 12kw growatt doesn't stack, so that's not an option for my setup.
edit: I did some more research, plus I went ahead and called Signature Solar and spoke with the Sales Manager (Brent) who was SUPER helpful! Adding the answers that I found inline below, in case they're useful for anyone else later on.
I could use 4 of these stackable growatt 5,000 ES inverters instead. Questions:
1)How does the max solar charge current work when these are in parallel? Does it stack the max currents? e.g.: if all 4 were paralleled, then would the max charge current be 400 amps? That would fit with my max charge current for a 1.5d recharge period.
A) Yes, these would need a transformer, and should do 2 inverters -> 1 transformer
2)Would an auto-transformer be needed in this setup?
A) yes
3)The panel configuration I was thinking is 4s12p. How do the charge controllers send enough current into the batteries when the total current coming in from the panels at max power would only be 115.92amps? (12 parallel x 9.66 amps per panel)
A) actually, a better configuration would be two of each: 7s2p, and 6s2p, total of 4 arrays
4) How do I figure out or calculate how far away the solar panels can be from the house?
A) apparently with PV wire anything <200 feet is a safe bet
4a) With the 4s12p (am I notating that correctly, or is it parallel count/series?) configuration that I was thinking, this would still only be a single positive wire and single negative wire coming into the house, right?
A) yes, 1 pair (+/-) home run PV wire per array, but note that for the inverter PV input, you need 1 array per MPPT input (many large inverters have >1 MPPT input on them)
4b) If so, would these individual lines be split into 4 somehow and sent into each inverter? ?
A) no, have 4 sets (+/-) of PV wires for 4 different panel arrays
5) I couldn't find anything on the spec sheet for the inverters on this, but if the incoming wattage from the panels is higher (due to being cold, etc), can the inverters automatically clip the incoming power without being damaged?
A) (only 90% certain on this one) based on a thread here with an over-paneling whitepaper, I don't think the growatt inverters support clipping, so you need to stay below the 6kw PV input per inverter
I would really appreciate any input or help you all have about this! I want to make sure I get everything 100% planned out exactly before I go purchase ~$32,000 worth of solar equipment... ??
I don't know if it's worth mentioning, but I am planning to buy everything I can from signature solar. Any discount codes I can use? ?
Thanks so much!
Basic background info:
- Building a large cabin in the woods
- Designing for being fully off-grid year-round
- Will install a large backup propane generator as a just-in-case (pays to be prepared)
- Solar panels will be ground-mounted
- Prefer the solar panels be as far as science allows from the house
I'm trying to design a system that operates year-round without needing to pull from a generator, but it's OK if it needs a few days here and there.
Note: I have already planned out my power usage using the spreadsheet provided by this forum, thank you!
I am trying to pick equipment to use. I was thinking a 48v system with:
* 2 pallets of these Hyundai 390w panels, planning to use 48 panels for a max peak of 18,720w
* 57.6 kWh of these LifePower4 batteries in 2 separate server-racks
-- this should be ~2 days of full backup power, assuming 48 hours of zero solar production
edit:
So, the 12kw growatt doesn't stack, so that's not an option for my setup.
edit: I did some more research, plus I went ahead and called Signature Solar and spoke with the Sales Manager (Brent) who was SUPER helpful! Adding the answers that I found inline below, in case they're useful for anyone else later on.
I could use 4 of these stackable growatt 5,000 ES inverters instead. Questions:
1)
A) Yes, these would need a transformer, and should do 2 inverters -> 1 transformer
2)
A) yes
3)
A) actually, a better configuration would be two of each: 7s2p, and 6s2p, total of 4 arrays
A) apparently with PV wire anything <200 feet is a safe bet
A) yes, 1 pair (+/-) home run PV wire per array, but note that for the inverter PV input, you need 1 array per MPPT input (many large inverters have >1 MPPT input on them)
A) no, have 4 sets (+/-) of PV wires for 4 different panel arrays
A) (only 90% certain on this one) based on a thread here with an over-paneling whitepaper, I don't think the growatt inverters support clipping, so you need to stay below the 6kw PV input per inverter
I would really appreciate any input or help you all have about this! I want to make sure I get everything 100% planned out exactly before I go purchase ~$32,000 worth of solar equipment... ??
I don't know if it's worth mentioning, but I am planning to buy everything I can from signature solar. Any discount codes I can use? ?
Thanks so much!
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