enphase IQ8 + solark

[ImAnIdiotPleaseBePatient]

So my Florida home is getting slowly closer to its completion date, and I have a pretty competitively priced install for 35kw of solar installed with iq8s and Qcells, but I really don't want to pay for their proprietary battery system, so I've been debating about ways to remedy this with Solarks/GSL/Lux (looking like probly solarks). The issue I am running into on designing the system is that a single Solark only takes in 19.2kw through it's gen port for AC coupling. With two Solarks in parallel, can you "split" the input from the iq8's into both Solarks (maybe a breaker for each off of the enphase box or something), thereby giving you a total of 38.4kw of AC coupling?

If not, I was considering just doing 19.2kw worth of iq8+, AC coupling that to a single Solark (or two in parallel), and possibling adding some DC coupled solar down the road. Just trying to make sure I don't make any huge mistakes before I pull the trigger on the grid tied system. I'd love to do it all myself (new metal roof so I can use those neat non-penetrating racking systems), but Florida requires a licensed contractor to get grid-tied.

Any info or ideas would be awesome! Would like to do as much as I can myself once the grid-tie is approved.

 

[Shimmy]

It's kind of important to understand how much battery you expect to install to give help there. 38kW of solar is pretty significant, but there are multiple ways to deal with it.

 

[ImAnIdiotPleaseBePatient]

Was planning on around 90kwh or so, give or take. 60kwh minimum though.

 

[Shimmy]

Would you go with two 15k's in a perfect world, or do you see your home's demand satisified with a single unit?

Honestly, with that large of a system I would want a single party to be turnkey responsible for it. There is a lot of complexity and risk with whatever you do. I don't see the value the IQ8's are bringing you if you are going to add all-in-one's that have the same MPPT capacity built in.

 

[ImAnIdiotPleaseBePatient]

Definitely would go with two in a perfect world. I have the nightmare scenario house with all electric everything, no gas/propane, plugin hybrid car, and tons of LED lights powering my wifes tropical plant etsy store that run for 10 hours per day (with extra air conditioning)

Fortunately, the LEDs are linked and can be dimmed down to very little amps in case of an outage.

 

[ImAnIdiotPleaseBePatient]

I honestly cannot find anyone that will install solarks at a reasonable price, and the warranty/redundancy provided on the IQ8's is fantastic.

 

[Ampster]

If not, I was considering just doing 19.2kw worth of iq8+, AC coupling that to a single Solark (or two in parallel), and possibling adding some DC coupled solar down the road

I would seriously consider doing the max DC coupling first because that will give you more flexibility with AC coupling. It all works seamlessly when the grid is up. But if you have frequent power outages, you are going to need lots of DC coupled solar.

 

[ImAnIdiotPleaseBePatient]

I would seriously consider doing the max DC coupling first because that will give you more flexibility with AC coupling. It all works seamlessly when the grid is up. But if you have frequent power outages, you are going to need lots of DC coupled solar.

If I could find someone that could install a dual Solark setup with a reasonable $/watt, I would pull the trigger, but the quotes I got are through the roof. But aside from that, the Solark should be able to use all the ac coupled solar power in a power outage anyways, although I know I'll lose some efficiency from the extra ACDC conversions.

 

[Ampster]

but the quotes I got are through the roof.

Probably because of the Rapid Shut Down requirements, which micros solve.

But aside from that, the Solark should be able to use all the ac coupled solar power in a power outage anyways, although I know I'll lose some efficiency from the extra ACDC conversions.

I am new to SolArk and am still trying to confirm that is the case. There is a whole thread about that and the more DC coupled solar you have the better chance AC coupling will work in a grid down situation. Let me know if you need a link to to a recent thread about issues with AC coupling when grid down?.

 

[ImAnIdiotPleaseBePatient]

Now need, I've read the entire thread you're talking about, but most people I've run into haven't had much issues with the 15k being able to freq shift the micros into action.

I should also probably specify that the difference in price between the dual Sol Ark quote and the iq8 quote was so large that... no joke... I could have the entire 35kw of iq8s installed, buy TWO sol ark 15ks, 80kwh of rack batteries, and they would be about equal!

$3.37 per watt vs $2.25 per watt

 

[Ampster]

Now need, I've read the entire thread you're talking about, but most people I've run into haven't had much issues with the 15k being able to freq shift the micros into action.

I agree the economics drive the decision, especially since power outages, though inconvenient, only occur in my region less than one percent of the time. That is why I have 7.9 kW of AC coupled solar and 2kW of DC coupled solar on a patio cover which did not require expensive Rapid Shut Down. The AC coupled micros on my roof have native RSD.

 

[ImAnIdiotPleaseBePatient]

DC coupled solar on a patio cover which did not require expensive Rapid Shut Down

Well, with regard to what I may do in the future with DC-coupling.... heh

 

[Shimmy]

Maybe your expectations are unreasonable here, just penciling it out. With ~75 panels, the IQ8 has about a $5,000 premium over Tigo RSD modules. Two SolArk's are $17,000, so a net increase of $12,000 in materials cost going with SolArk, or about $0.50/W. There is a bit more installation cost, so your premium isn't that far off, so it might make sense to negotiate.

Your other options are to look at a different inverter arrangement or a mix-and-match solution. I have a feeling that once you go that direction you are going to see a $0.50/W labor premium with anybody.

Your "best" solution is likely to do half IQ8's and half DC-coupled to a single SolArk. Getting it done economically is another matter though.

 

[ImAnIdiotPleaseBePatient]

I hate it when other people are right.

 

[wheisenburg]

AC coupling SEEMS like a great idea. IQ8 inverters are extremely reliable and they work great on-grid. The main problem with AC coupling is that I can't find anyone that has made a 100% AC coupled IQ8 system actually work off-grid with a hybrid inverter. Full Enphase solutions with their controller and battery does work, but nothing else I can find. If I am wrong, please let me know what Hybrid inverter, battery and Enphase grid profile you got to work.

Just because the marketing people tell you AC coupled "Should work" does not mean that it actually does work. Apparently pair some AC coupled with DC coupled does work.

 

[Ampster]

If I am wrong, please let me know what Hybrid inverter, battery and Enphase grid profile you got to work.

I got Enphase micros to work with an Outback Skybox. The challenge with AC coupling is to have consistent loads so the micros do not have to be curtailed. Also the hybrid has to have a a good algorithm to modulate the micros.