Another recommendation needed

TexasSun

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Nov 5, 2021
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I thank the fellows who helped with the last configuration.

But apparently all of my friends are thinking about solar, and another friend spent 2 hours talking to me about it yesterday.

OK, currently he has nothing. He was going to spend $3500 just to install a 500 gallon propane tank to run a generator, and I thought that was nuts and it would go a good way toward a solar setup. He's looking at 13kW of panels, with the possibility of upgrading to 20kW. He wants it to be grid-tie producing power & paying for itself normally, and adding batteries so it'll work in a grid-down situation. Again, local here in Central Texas and the grid-down ice storm from February woke him up.

I've got him lined up with some great solar panels. $0.283 per watt! Looking for guidance first on the inverter/charger. I've only worked with smaller units, up to 12kW. I don't know if it's better to go with stacking units, or a single larger system. Or, get one system that is 'smarter' (AC coupled), like the Outback Skybox, and find a less expensive UL1741SA compliant that can operate as a slave to the Skybox? Or consider a bigger Growatt system? I'm all ears and open to reasonable suggestions.

Once I pick an inverter, THEN we can get into battery discussions (yes, I know, it changes by the day... hence why I'll save the battery discussion for later)
 

houseofancients

Photon Sorcerer
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Nov 29, 2019
Messages
1,095
i think a hybrid setup would be the thing he wants, however 3500 will not cut it.

i think , depending on inverter brand , that would be enough for just half the inverter.
also you really need get more info on his peak usage and daily usage, as that will heavily impact the inverter size and battery size
 

Bossrox

Solar tinkerer
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May 21, 2021
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Location
Columbia, SC
I'd take a gander at some Growatt stuff. I know they have a 12kw with built in charge controller, can't beat their price & warranty but it's China made & tho it has a good reputation, political relations between us might scrap any future service issues.
 

TexasSun

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i think a hybrid setup would be the thing he wants, however 3500 will not cut it.

i think , depending on inverter brand , that would be enough for just half the inverter.
also you really need get more info on his peak usage and daily usage, as that will heavily impact the inverter size and battery size
He really doesn't use much. His house is all electric, and his monthly bill is about $100 (I saw the annual average). So call it $3.50 a day, or about 30-35kW per day. So even at 13 kW, he'll be over producing. However his son might put a place on the ranch, so that's what I think he's anticipating (and yeah, just what I want to hear, more adult kids moving back home!).

However his wife does a fair bit of cooking, so that might be the better part of their electric bill.

I've seen lots of the Growatt smaller units, 6 or 7 kw size. However I've not seen where someone actually has the larger units. Anyone know anyone who has a larger inverter, here in the US?
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
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Rural NE Ontario Canada

The answer sometimes is staring right at you.
 

TexasSun

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Steve,
I do like that option. The direct link to the inverter is https://watts247.com/product/lv6548...erter-4kw-250v-mppt-bms-ul1741-built-in-wifi/

He needs a pair, 6.5kW @ 120v each, two give him 13kW @ 240v. $1600 each, so $3200. They do suck 80w at idle per unit, so that isn't great. And he can upgrade to 4 units for 26kW capacity!

I just spoke with my buddy, he's going to check this out. It's sounding like he's going to hold off on getting batteries for now (hope he doesn't regret that later, but we all have only so much to spend).

Thanks for the link Steve.

I've also found that some of the Growatt systems might work. I've got a call into them... we'll see what data they have.
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
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OOPS that's trouble that is waiting to fall on you. DON'T DO THAT !

Get a 240VAC Split Phase AIO and stack those... don't play the 120V on one side 120V on the other and try to flip it so you get split phase... Remember they operate in the opposite phase relative to leg. (sorry extremely tired now, need bed)

240V split phase inverters do what they are supposed to and when stacked they operate in synch... it is designed for that & cost difference IS negligible in teh grand scheme.

ALSO BE CAREFUL ! There is 220/230 V units but SINGLE PHASE @ 50Hz (EU & Asia)
North America = 240VAC Split Phase @ 60Hz. Sadly some people don't read the fine print and get the wrong one and that never ends well.
 

TexasSun

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Nov 5, 2021
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23
OOPS that's trouble that is waiting to fall on you. DON'T DO THAT !

Get a 240VAC Split Phase AIO and stack those... don't play the 120V on one side 120V on the other and try to flip it so you get split phase... Remember they operate in the opposite phase relative to leg. (sorry extremely tired now, need bed)

240V split phase inverters do what they are supposed to and when stacked they operate in synch... it is designed for that & cost difference IS negligible in teh grand scheme.

ALSO BE CAREFUL ! There is 220/230 V units but SINGLE PHASE @ 50Hz (EU & Asia)
North America = 240VAC Split Phase @ 60Hz. Sadly some people don't read the fine print and get the wrong one and that never ends well.

Steve,
Are you aware of systems failing because they were used this way? The unit that you suggested is a 120Vac unit, and it is designed to run in pairs to generate 240Vac (two 120V legs, 180degrees out of phase). In fact it appears that you can even take 3 units & generate 3 phase power (not needed here). You do add communication wiring so that the units are aware of each other, and one acts as the master & the others as slaves. And yes, I'm well aware of the 50 Hz / 60 Hz issue.

Do you have a 240Vac inverter you'd recommend instead of this one?
Thanks
 

Steve_S

Offgrid Cabineer, N.E. Ontario, Canada
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Location
Rural NE Ontario Canada
Some info I add because who knows who will come afterwards reading the thread. You'd be surprised how many have no idea about 50 or 60hz let alone the rest.

Growatt and even MPP have 120 or 240 systems, if you want 240 then start with that Base Model and parallel up for more output. KISS is always best and MOST ESPECIALLY with solar gear. I am aware that paralleled 120V AIOs can be programmed as you mentioned but if one pops you got issues. People have had failures due to misconfiguration and not RTFMing. Growatt includes most of the comms gear by default and can interact with battery packs using CanBus/RS485 pending on model, and battery packs as well.

VICTRON is a Tier-1 product and some of the best goodies out there for this type of build but comes with an extra cost but minimal longterm worry.

IF I was to build my system TODAY, Budget Build (for me) would be Growatt AIO Based, Best Build would be Victron. There are 3 other brands I would seriously consider but I won't mention that as it would toss open a Bag Of Cats which I have no interest in furtling with. They are not discussed in this forum.
 

SolarPrep

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TexasSun: First thing to do is check with the AHJ (who has authority there?) and find out if you need UL listed. If so, your choices will be greatly reduced. If not, I'd second Victron. The new Phocos model looks nice, and it will be UL approved.
 

TexasSun

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There is a requirement for UL in this location, no question about it.

I don't see where the Victron system has any real benefits. A short 2 year warranty, only 6kW inverter, and not UL tested/approved? Yikes, I'm running away from that. Compare that to Sol-Ark 12k, with a 10 year warranty. Yup, more expensive, but quality doesn't come free. This setup does not need that level of quality, but bare minimum is that it needs to be legal here (UL)!
 

TexasSun

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I found an interesting option, the Growatt MIN 7600 TL-XH-US (in the family, multiple sizes available from 3kW to 11.4kW).

Very interesting. I like the specs on it... running two of these interconnected will give all the power required. And each unit is under $1500, add a few hundred for an auto transformer. Call it under $3500 for 16.2kW of PV output power. 10kW of battery-based output power in a grid-down situation. Even AC coupling capability. Wow. And a 10 year warranty.

Only thing I'm not fond of is that it requires a 'nominal' 400V dc battery system. You can buy their batteries (awaiting pricing locally). That would basically be 32 batteries in series at 12v batteries. Per string. And 400Vdc can hurt if you put your fingers across them. But, if that's the only shortfall, this unit clearly wins hands-down.

Any comments for or against this unit?
Thanks.
 

TexasSun

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Well it just gets more and more interesting... Heard back.

I'm told that the MIN series from Growatt only works with Growatt's batteries, the ARO series. They run $6600 for 10kW-hrs of storage... definitely on the expensive side.

Anyone know if these work with other batteries, ideally DIY batteries? I know, it'll 'void' the warranty (if there is an issue and they catch me!). But, will it work?
 

SolarPrep

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There is a requirement for UL in this location, no question about it.

I don't see where the Victron system has any real benefits. A short 2 year warranty, only 6kW inverter, and not UL tested/approved? Yikes, I'm running away from that. Compare that to Sol-Ark 12k, with a 10 year warranty. Yup, more expensive, but quality doesn't come free. This setup does not need that level of quality, but bare minimum is that it needs to be legal here (UL)!
Victron has 5 year warranties. Great equipment. It sucks that they don't get UL approval, except for a very few 12v or 24v units.

If you need UL (most people do now, even if they don't know it) Growatt, MPP and many others are out of the question. A few of them give misleading comments like "Ul Compliant". It isn't enough. Certification has to come though approval by OSHA though their NRTL program.

One that is supposedly going to have UL Listing is the new 6500 Phocos.
 

SolarPrep

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Jul 15, 2021
Messages
229
I found an interesting option, the Growatt MIN 7600 TL-XH-US (in the family, multiple sizes available from 3kW to 11.4kW).

Very interesting. I like the specs on it... running two of these interconnected will give all the power required. And each unit is under $1500, add a few hundred for an auto transformer. Call it under $3500 for 16.2kW of PV output power. 10kW of battery-based output power in a grid-down situation. Even AC coupling capability. Wow. And a 10 year warranty.

Only thing I'm not fond of is that it requires a 'nominal' 400V dc battery system. You can buy their batteries (awaiting pricing locally). That would basically be 32 batteries in series at 12v batteries. Per string. And 400Vdc can hurt if you put your fingers across them. But, if that's the only shortfall, this unit clearly wins hands-down.

Any comments for or against this unit?
Thanks.
Not UL listed.
 

Hedges

I See Electromagnetic Fields!
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10,681
OK, currently he has nothing. He was going to spend $3500 just to install a 500 gallon propane tank to run a generator, and I thought that was nuts and it would go a good way toward a solar setup. He's looking at 13kW of panels, with the possibility of upgrading to 20kW. He wants it to be grid-tie producing power & paying for itself normally, and adding batteries so it'll work in a grid-down situation. Again, local here in Central Texas and the grid-down ice storm from February woke him up.

Is the purpose of a battery backed system (rather than pure grid-tie) to provide heat during a power outage?
"Propane tank" suggests he doesn't have natural gas (or is afraid it will cut off during freezing again.)
For heat, either need a huge battery for electric heat, or a fuel source.
Assuming some kind of furnace, the electric load is blowers, so inverter needs to be able to start and run those.
Whatever volts x amps = watts (or VA) is shown on the motor, multiply by 5 to get surge current for startup, which might last a second. That is what inverter has to provide for that amount of time. If label shows "LRA" Locked Rotor Amps, use that instead of 5x running current.

If he has electric heat, then some fuel based backup heat could be a better way to go. Wood pile, coal, or oil to fire a water heater, piped to radiator inside home? (Batteries aren't practical except for just overnight power of a small heatpump like in an RV.)
 

TexasSun

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Nov 5, 2021
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Is the purpose of a battery backed system (rather than pure grid-tie) to provide heat during a power outage?
"Propane tank" suggests he doesn't have natural gas (or is afraid it will cut off during freezing again.)
For heat, either need a huge battery for electric heat, or a fuel source.
Assuming some kind of furnace, the electric load is blowers, so inverter needs to be able to start and run those.
Whatever volts x amps = watts (or VA) is shown on the motor, multiply by 5 to get surge current for startup, which might last a second. That is what inverter has to provide for that amount of time. If label shows "LRA" Locked Rotor Amps, use that instead of 5x running current.

If he has electric heat, then some fuel based backup heat could be a better way to go. Wood pile, coal, or oil to fire a water heater, piped to radiator inside home? (Batteries aren't practical except for just overnight power of a small heatpump like in an RV.)
Not worried about heat. In fact this fellow just ordered a wood-burning stove. And I tell everyone that solar is a horrible solution for heat or cooking. Fan/lights/fridge/well are what solar is great for running. And no natural gas is available (out in countryside).

And I can confirm that the Growatt units require their $$$ batteries, so it's off the list for that plus not UL listed.
 

SolarPrep

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TexasSun: "The Colorist" is located in Belize, is a great guy, and will be selling the Huayu here. He is very knowledgeable. He is also working with the Megarevo line.

He was selling a lot of Deye equipment until SolArk took care of that by forcing Deye to stop letting people sell here.

Companies who want to sell here are going to have to get their stuff certified. It will be better for many of us if they do.
 
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