Advice on small grid tie system 6Kwatts

[RichBenn]

i am starting a design of a grid tie system with net metering for my house. Did this almost 10 years ago, and it did not pencil out due to our low energy costs in Northern Nevada. But I see things have changed, so I think it’ll work.

My current usage would be covered by a 4-5k system but I’m going to fix the outdoor spa and maybe add some new electrical loads, so 6K (probably more) is the target. Our power is reliable here, so no battery backup. Classically we have a lot of sun but periodic snow loads and high altitude. RELIABILITY is my most important criteria. I’m looking at:

Ground mount 400 watt bifacial panels at the south end of our house.
Ironridge racking(helps figure wind and snow load and drawings for me)
Either Fronius Primo or SMA Sunny Boy smart grid tie inverter.
75 ft DC conduit run from panels to inverter, which would be located outside near the power panel and meter.

Of course I have questions:
1. Anybody have experience with these inverters, or can suggest another “reliable” UL listed grid tie inverter in the under 10 Kwatt range? I’m not interested in hybrid or off-grid inverters and would like the MPPT and inverter portions in one box.
2. I’m a little sketchy on disconnects. I believe NEC 2017 requires a PV array(DC) and post inverter(AC) disconnect and that no rapid shutdown is needed as it is not mounted on the roof. So is the DC disconnect is located at the PV array and the AC disconnect is between the inverter and grid?
3. Anybody have experience with ground screws in rocky soil(for the ground mounts)? I’ve never used them before, and am leaning towards concrete.
4. I want to mount the inverter on my Northeast wall. No direct sun except for a little in the morning, but wondering if that’s going to affect longevity?

I’m sure I’ll have more questions. Hope this is the right section to post this.

Thanks in advance for any advice,
Rich

 

[1201]

Get a growatt 6kw min tl-x inverter.
$750

15x 400w Talesun bifacials $1620

Do two strings.

Or a 7.6kw min tl xh $1000
600v in Nevada you might be able to do one 15s string

That should pencil out.

Most inverters have a DC disconnect at the inverter but many choose to add separate fuses even though series strings don't need them.

You need a knife switch disconnect near the main meter

 

[RichBenn]

Get a growatt 6kw min tl-x inverter.
$750

15x 400w Talesun bifacials $1620

Do two strings.

Or a 7.6kw min tl xh $1000
600v in Nevada you might be able to do one 15s string

That should pencil out.

Most inverters have a DC disconnect at the inverter but many choose to add separate fuses even though series strings don't need them.

You need a knife switch disconnect near the main meter

I see many poor ratings for Growatt and min, which is why I wasn’t considering them. Seems most failures are a couple years down the road, and replacements are not available. Reliability is my main criteria. Don’t want to touch the system after it’s installed, which is why I was going name brand.

Wish we could get actual, not anecdotal experiences on these Chinese makers, but it is what it is. There is some actual failure rate data on the bigger names, but even some of that is hidden.

I’m debating one or two strings. Probably two, as there may be some partial shading in winter.

I

 

[1201]

I see many poor ratings for Growatt and min,

Where?

which is why I wasn’t considering them. Seems most failures are a couple years down the road, and replacements are not available. Reliability is my main criteria. Don’t want to touch the system after it’s installed, which is why I was going name brand.

Fair enough but isn't fronius like 4x the price for the same wattage?

Wish we could get actual, not anecdotal experiences on these Chinese makers, but it is what it is. There is some actual failure rate data on the bigger names, but even some of that is hidden.

I haven't seen it

I’m debating one or two strings. Probably two, as there may be some partial shading in winter.

I

 

[Kuma]

i am starting a design of a grid tie system with net metering for my house. Did this almost 10 years ago, and it did not pencil out due to our low energy costs in Northern Nevada. But I see things have changed, so I think it’ll work.

My current usage would be covered by a 4-5k system but I’m going to fix the outdoor spa and maybe add some new electrical loads, so 6K (probably more) is the target. Our power is reliable here, so no battery backup. Classically we have a lot of sun but periodic snow loads and high altitude. RELIABILITY is my most important criteria. I’m looking at:

Ground mount 400 watt bifacial panels at the south end of our house.
Ironridge racking(helps figure wind and snow load and drawings for me)
Either Fronius Primo or SMA Sunny Boy smart grid tie inverter.
75 ft DC conduit run from panels to inverter, which would be located outside near the power panel and meter.

Of course I have questions:
1. Anybody have experience with these inverters, or can suggest another “reliable” UL listed grid tie inverter in the under 10 Kwatt range? I’m not interested in hybrid or off-grid inverters and would like the MPPT and inverter portions in one box.
2. I’m a little sketchy on disconnects. I believe NEC 2017 requires a PV array(DC) and post inverter(AC) disconnect and that no rapid shutdown is needed as it is not mounted on the roof. So is the DC disconnect is located at the PV array and the AC disconnect is between the inverter and grid?
3. Anybody have experience with ground screws in rocky soil(for the ground mounts)? I’ve never used them before, and am leaning towards concrete.
4. I want to mount the inverter on my Northeast wall. No direct sun except for a little in the morning, but wondering if that’s going to affect longevity?

I’m sure I’ll have more questions. Hope this is the right section to post this.

Thanks in advance for any advice,
Rich

Did a lot of research and spoke with a couple retailers/venders last year that sell multiple brands and one even said SMA is the "gold standard". Also, the Fronius inverters that I researched had a mechanical fan for cooling. SMA has a 10 year warranty and for another $500 - 30% for Federal Tax Credit gets you another 10 or 15 years depending on the model. Installed a 6.8kw system with a 5kw SMA Inverter.

In Nor Cal no ac disconnect was needed between inverter and service panel. This is roof mount and inverter is 2 ft from service panel. I suggest doing a walk in to your bldg dept with a rough draft of your system. I did this and the bldg dept was very receptive and answered all questions.

Direct sun can eventually make the front panel LCD display hard to read. Some have made a little flap to protect it.

btw - SMA and Fronius are not popular on this site. One or two people are experienced and may reply.

 

[RichBenn]

Where?


Fair enough but isn't fronius like 4x the price for the same wattage?


I haven't seen it

A great review is on solarquotes.com.au
Or you can search google - Reddit and others are full of criticism
Even a global search on DIY solar using terms “Growatt failure”

Fronius is not 4x the price. One can get a 6K for $1400 (more if you want wifi and not direct connect ethernet)
Maybe their newest stuff is good. Specs are. But… At over 70, and a long time engineer, I’m just done trying to save a nickel. My remaining time is worth more than money.

China can make great stuff or crap. Brands like SMA and apple have good products, but they design and monitor the build quality and components carefully.

 

[RichBenn]

Did a lot of research and spoke with a couple retailers/venders last year that sell multiple brands and one even said SMA is the "gold standard". Also, the Fronius inverters that I researched had a mechanical fan for cooling. SMA has a 10 year warranty and for another $500 - 30% for Federal Tax Credit gets you another 10 or 15 years depending on the model. Installed a 6.8kw system with a 5kw SMA Inverter.

In Nor Cal no ac disconnect was needed between inverter and service panel. This is roof mount and inverter is 2 ft from service panel. I suggest doing a walk in to your bldg dept with a rough draft of your system. I did this and the bldg dept was very receptive and answered all questions.

Direct sun can eventually make the front panel LCD display hard to read. Some have made a little flap to protect it.

btw - SMA and Fronius are not popular on this site. One or two people are experienced and may reply.

Nice to know. Thanks for the info!

 

[1201]

A great review is on solarquotes.com.au
Or you can search google - Reddit and others are full of criticism
Even a global search on DIY solar using terms “Growatt failure”

Fronius is not 4x the price. One can get a 6K for $1400 (more if you want wifi and not direct connect ethernet)
Maybe their newest stuff is good. Specs are. But… At over 70, and a long time engineer, I’m just done trying to save a nickel. My remaining time is worth more than money.

China can make great stuff or crap. Brands like SMA and apple have good products, but they design and monitor the build quality and components carefully.

Ok I thought it was like 4x. I'm happy with my growatt but for only $650 more and even less after tax refund, the fronius makes sense.

Also interfaces well with victron if you ever decide to ac come to a battery inverter