Help comparing 3 Solar Project Bids

[flyakite]

A. 6.48Kw 16 panels Q. PEAK DUO BLK ML-G10 Series 405watts
16 Solaredge optimizers
1 Solaredge 7.6 KW Single Phase Inverter w/HD Wave Technology
2 strings of 8
$18,183 $2.81 watt


B. 6.72Kw 16 panels REC Solar - SPR-REC420AA 420watts
16 inverters SunPower SPR-A5

$20,161 $3.00 watt

C. 6.02Kw 14 panels Mission Solar Energy - MSE430SX9Z 430watts​

7 inverters iCP-720E (7x)

$17,759 $2.95/watt azimuth 231 degrees (SW)

---

seeking feedback comparing the 3 systems. all feedback greatly appreciated. thank you

 

[sunshine_eggo]

B costs more than A

B will handle shade better than A.

 

[zanydroid]

B costs more than A

B will handle shade better than A.

Why would the microinverters handle shade better than the optimizer system? Both have per-panel MPPT.

I think it comes down to whether you believe in SolarEdge or Enphase more as a company (The SPR-A5 appear to be rebadged Enphase)

SolarEdge has a single point of failure (inverter), and there's probably a lot more complaining about SolarEdge on social media ?

That's about all I can objectively say about this.

 

[sunshine_eggo]

I've always been under the impression that microinverters are more effective than optimizers. Not by a lot.

 

[zanydroid]

I've always been under the impression that microinverters are more effective than optimizers. Not by a lot.

? Could be. The SolarEdge optimizers need to get some coordination help from the string inverter to stay within the max string voltage limit. Not sure if they maintain constant current (within min and max voltage limit) or both constant current and constant total voltage. The microinverters will happily do their own thing.

From the perspective of how lazy solar installers design systems, they're not that different.

 

[Hedges]

Will you want battery backup later?
Decide and price it out upfront. GT PV selection will paint you into a corner.

I prefer string inverters, but I'm not a fan of Solar Edge due to what failure rate info I have seen (but that may not apply to all models or locations.)
String inverters, all panels in a given string should be of a single orientation. So microinverters or at least optimizer may work out better for some situations.

I use SMA. I will be installing a couple of their Sunny Boy Smart Energy, which optionally takes an (expensive) battery. I understand Fronius is good too.

 

[glandpuck]

Hmm. It seems to me that Sunpower is quoting on an AC coupled system while Solar Edge is quoting on a DC coupled system. The Solar Edge has shade optimizers on each panel meaning if a chimney or a utility pole casts a shadow across the array, each panel's output is optimized individually rather than the entire array being reduced to the lowest output of a panel.

I believe that adding batteries to a solar edge system is a rather closed loop proprietary endeavor at this time. Adding batteries to a Sunpower system would mean adding a battery system that accepts AC coupling as the PV source.

In my case, I have my panels divided into 3 arrays. I have a high voltage hybrid inverter as found across this website and I have lithium battery stacks. It's easy to maintain. The batteries are closed loop, plug and play and forget. the panels can be easily replaced or updated because they are not tied to micro inverters or optimizers on each panel. If there is a storm with damage, only the panels need serviced with each PV wire, not local microinverters or optimizers.

The systems you have been quoted on were designed to make installation of the system quick and easy. Repair, flexibility not so much down the road.

 

[flyakite]

Will you want battery backup later?
Decide and price it out upfront. GT PV selection will paint you into a corner.

I prefer string inverters, but I'm not a fan of Solar Edge due to what failure rate info I have seen (but that may not apply to all models or locations.)
String inverters, all panels in a given string should be of a single orientation. So microinverters or at least optimizer may work out better for some situations.

Will you want battery backup later?
Decide and price it out upfront. GT PV selection will paint you into a corner.

I prefer string inverters, but I'm not a fan of Solar Edge due to what failure rate info I have seen (but that may not apply to all models or locations.)
String inverters, all panels in a given string should be of a single orientation. So microinverters or at least optimizer may work out better for some situations.

I use SMA. I will be installing a couple of their Sunny Boy Smart Energy, which optionally takes an (expensive) battery. I understand Fronius is good too.

No, will not want a battery back up later. And will not want to add panels later either. Yes, all panels will be in the same orientation.

I use SMA. I will be installing a couple of their Sunny Boy Smart Energy, which optionally takes an (expensive) battery. I understand Fronius is good too. thanks for the input

 

[Hedges]

In that case price, reliability, actual capacity are about all that matter.
You don't need the optimizer feature that comes with Solar Edge module-level electronics or the total independence between microinverters. But you will need module-level RSD, which is include in those.

The SunPower system has 6.7kW of panels. (under most conditions, will produce up to 75% or 85% of that.) I can't find the inverter info, so don't know if they are undersized compared to panels, which is commonly done.

My preference would be a string inverter like from SMA, with the PV panels allocated across 3 MPPT according to voltage limits. There would be RSD boxes for each one or two panels.

Your location mapped to here, is this you? If so, almost my neighbor.

Castalia

www.google.com

What kind of mounting structures, and what is your roof?
Installers want to slap it on fast. That means lag screws through shingles, and caulk to seal it. (But roofs are designed with shingling to spill water, not adhesive suppose to be water tight to old dirty surfaces.)
I'm planning to use flashing and standoffs, even though far more work.
Any roof leaks could wipe out all power savings and much more.

If you are in the Bay Area as the map showed, do you have a PG&E NEM 2.0 reservation?
If not under NEM 2.0, rather will be NEM 3.0, don't do it. Without batteries, the system will be a terrible deal. Unless you consume near 100% of power at the moment it is generated.
You will also be forced onto a time of use rate plan that is likely unfavorable.

 

[hwy17]

It seems to me that Sunpower is quoting on an AC coupled system while Solar Edge is quoting on a DC coupled system.

I never heard string inverters called DC coupled before. DC coupling is when you feed into a DC charge controller to a battery.

I get your angle, but the terminology is wrong. String inverters and microinverters are both AC coupled systems.

 

[flyakite]

In that case price, reliability, actual capacity are about all that matter.
You don't need the optimizer feature that comes with Solar Edge module-level electronics or the total independence between microinverters. But you will need module-level RSD, which is include in those.

The SunPower system has 6.7kW of panels. (under most conditions, will produce up to 75% or 85% of that.) I can't find the inverter info, so don't know if they are undersized compared to panels, which is commonly done.

My preference would be a string inverter like from SMA, with the PV panels allocated across 3 MPPT according to voltage limits. There would be RSD boxes for each one or two panels.

Your location mapped to here, is this you? If so, almost my neighbor.

Castalia

www.google.com

What kind of mounting structures, and what is your roof?
Installers want to slap it on fast. That means lag screws through shingles, and caulk to seal it. (But roofs are designed with shingling to spill water, not adhesive suppose to be water tight to old dirty surfaces.)
I'm planning to use flashing and standoffs, even though far more work.
Any roof leaks could wipe out all power savings and much more.

If you are in the Bay Area as the map showed, do you have a PG&E NEM 2.0 reservation?
If not under NEM 2.0, rather will be NEM 3.0, don't do it. Without batteries, the system will be a terrible deal. Unless you consume near 100% of power at the moment it is generated.
You will also be forced onto a time of use rate plan that is likely unfavorable.

Hedges,
I wish I was almost your neighbor, but no, it is Castalia, OH 44824. Both estimates are using the IRONRIDGE Flush Mounting System.

last 12 months use: 14,854 KWH = 1,238/mo avg $1725 $143.75/mo avg home is all electric current generation rate 5.9 cents /kwh
see pic - panels would be installed on garage roof. I do not want to attach to house roof mainly to lessen damage if a leak, and ease of installation.

note: SREC rate is only $4 in Ohio. 1 salesman said I could opt to sell them to Pennsylvania which is around $43 - but I cannot verify if this is true.

also: I live in one of the cloudiest regions of the country, just below Lake Erie. That being said, 5 miles from my house they are starting to build the following -The proposed Wheatsborough Solar Project consists of an up to 125 megawatt solar-powered electric generation facility and an up to 50 MW battery-energy storage system located in Groton Township, Erie County.

thanks to all for input

 

[Quattrohead]

I never heard string inverters called DC coupled before. DC coupling is when you feed into a DC charge controller to a battery.

I get your angle, but the terminology is wrong. String inverters and microinverters are both AC coupled systems.

Solaredge system is DC to the inverter where it gets converted to 240v AC.
Enphase is 240v AC straight into your electrical panel via their combiner/monitoring system.
Both have RSD built in.

 

[glandpuck]

I never heard string inverters called DC coupled before. DC coupling is when you feed into a DC charge controller to a battery.

I get your angle, but the terminology is wrong. String inverters and microinverters are both AC coupled systems.

Enphase is an AC microinverter. The panel connectors are plugged directly into the microinverter mounted at the panel and the output is 240 volts AC current at about 1.0-1.2 amps per panel (give or take a little for panels power differences.) The "trunk wire" connects these microinverters in series up to a maximum of about 16 amps at 240 volts. These trunk wires can then be combined into larger amperages in parallel and out to the grid or battery backup.

The Solar Edge system used DC optimizers on each panel, not AC microinverters. Their combined output then goes to the solar edge inverter and the conversion to AC current takes place. From the solar edge website:

"Our most advanced generation of Power Optimizers provide cutting edge safety features, simplified wiring, and smart remote monitoring while continuing to: Boost panel-level production with DC optimization, despite shading or debris."

I think my original post above was quite accurate in describing the differences between the 2 systems.

 

[Hedges]

current generation rate 5.9 cents /kwh

Is there a separate transmission rate?
Is generation rate what they credit you for backfeed?

If you only pay five or 10 cents per kWh to buy power, forget PV unless you want backup power during grid failures.

Renewable Energy Credits I don't understand, because as a consumer I have no market here.

If RSD could be avoided, it would save money, especially for DIY installs. But maybe carport/garage requires and only ground mount or power shed, with DC stopping at inverter not on the house, is exempt.

Other face of roof, even if north facing, may be useful if you want power in summer for A/C or pool pumping.

 

[hwy17]

I think my original post above was quite accurate in describing the differences between the 2 systems.

Solaredge system is DC to the inverter where it gets converted to 240v AC.

If you guys are doubling down on calling string inverters "DC Coupled" I'm outta here. I don't know what to say.

 

[cs1234]

Solaredge system is DC to the inverter where it gets converted to 240v AC.
Enphase is 240v AC straight into your electrical panel via their combiner/monitoring system.
Both have RSD built in.

Both systems are shooting AC straight into your electrical panel. One of them does it at a centralized inverter, the other does it at each panel/microinverter.

I would describe both systems as AC grid tied systems.. if you wanted to do anything with them, with say a EG4 18KWPV, you would have to AC couple it to them to control them or have them bypass the EG4 and go straight into your utility and turn off when power from the utility is lost.

 

[zanydroid]

If you guys are doubling down on calling string inverters "DC Coupled" I'm outta here. I don't know what to say.

You can convert a string inverter system with no battery support to one that has solar panels DC coupled into a hybrid inverter. The original string inverter would need to be ripped out.

With microinverters, which are clearly AC coupled, it is not labor-efficient to add storage by DC coupling.

In the case of a SolarEdge, you would have to rip out the optimizers too, so there is little difference to microinverters, you have to AC couple. It doesn't fit neatly into the taxonomy and is inherently confusing.

These are a important complexity, cost, and system design consideration.

I would somewhat agree that it is inartful to call it DC coupled when there is no battery system involved yet. How would you call it?

 

[hwy17]

How would you call it?

I would call it AC coupled because of the way that it is.

Ease of conversion into a DC coupled system is a factor you can discuss, sure, but I am only offering a simple and clear terminology correction to @glandpuck . A string inverter is not DC coupled.

 

[Farm Boy]

A. 6.48Kw 16 panels Q. PEAK DUO BLK ML-G10 Series 405watts
16 Solaredge optimizers
1 Solaredge 7.6 KW Single Phase Inverter w/HD Wave Technology
2 strings of 8
$18,183 $2.81 watt


B. 6.72Kw 16 panels REC Solar - SPR-REC420AA 420watts
16 inverters SunPower SPR-A5

$20,161 $3.00 watt


seeking feedback comparing the 2 systems. all feedback greatly appreciated. thank you

Sense your close to the lake, I'd consider a ground mount system if you have the space. Easy to get lake snow off.

 

[cs1234]

I would somewhat agree that it is inartful to call it DC coupled when there is no battery system involved yet. How would you call it?

AC grid tied.. they are both AC grid tied systems.