4.5kW SolarEdge/LG System coming soon to San Diego

[subdriver97]

Assuming my only option is the SE3800 to comply with NEC 2011, I thought of the following:
1. Can the main breaker be degraded further to 95A or 90A to accommodate a 30A solar breaker?
2. Maybe I should consider Enphase, at least then if I want to expand I won't be limited by a SE3800. When I want to add more panels I will just need to do a service panel upgrade.

My immediate thought is I shouldn't just bite the bullet and buy into the service panel upgrade. Cash in hand is more worthwhile to me. Also the vendor is charging $2500 for the service panel upgrade so it would cheaper for me to have a difference vendor do it even considering if I don't have the 30% tax credit.

1. (first choice, if at all an option) My vendor replied to my idea of derating the service panel to 95A (With a 95A breaker I can do a 30A solar breaker and handle the SE5000) and stated that the minimum rating for residential with solar is 100A. I could see having a 100A minimum on the service panel rating for residential with solar, but I can't understand the reason for a minimum main breaker rating. What if I have a tiny 1 bedroom house and draw very little power? What else matters other than loading? Is there a NEC regulation regarding this or is it San Diego AHJ?

2. (second choice) I'm seriously considering installing 16 LG280 panels with Enphase M-250 inverters so I can defer the service panel upgrade to if and when I expand the system and I won't be limited by a SE3800.

3. A third possibility is to install a 16 LG280 panels with a SE3800 now. Then install an additional SE inverter if and when I expand. However this is less cost effective for a small number of panels and there is something like a 8 panel minimum to run a SE inverter.

[SoCalsolar]

Your main panel looks

Your main panel looks good for install a bit cramped but should be able to back feed at least 45amps for the solar since it is derated from 125 down to a 100. The center fed is likely to be more of an issue than the available amps for back feeding and the center fed issue will not be resolved by anything but an upgrade. Have them submit it to the city drawn up with original main panel and if the counter approves the drawings you may have just saved $2500. Of course when the counter and the inspector disagree usually the inspector wins. Worst case scenario you fail inspection and then upgrade the main panel for $2500.

[subdriver97]

Your main panel looks good for install a bit cramped but should be able to back feed at least 45amps for the solar since it is derated from 125 down to a 100. The center fed is likely to be more of an issue than the available amps for back feeding and the center fed issue will not be resolved by anything but an upgrade. Have them submit it to the city drawn up with original main panel and if the counter approves the drawings you may have just saved $2500. Of course when the counter and the inspector disagree usually the inspector wins. Worst case scenario you fail inspection and then upgrade the main panel for $2500.

How did you come up with the 45amps for solar? It's center-fed so limited to 100% of busbar rating, so max of 25A for solar with a 100A main supply, no?

[subdriver97]

1. (first choice, if at all an option) My vendor replied to my idea of derating the service panel to 95A (With a 95A breaker I can do a 30A solar breaker and handle the SE5000) and stated that the minimum rating for residential with solar is 100A. I could see having a 100A minimum on the service panel rating for residential with solar, but I can't understand the reason for a minimum main breaker rating. What if I have a tiny 1 bedroom house and draw very little power? What else matters other than loading? Is there a NEC regulation regarding this or is it San Diego AHJ?

Update: My vendor replied and stated that the minimum rating of a 100A main breaker is a SDGE rule.

[JBinCBad]

So to dumb this down further, do microinverters relieve the amperage required of the control panel? Ie if I want to the SE string inverter instead of panels with microinverters, could that possibly require a panel upgrade? Haven't considered that yet, nor have I committed between the string inverter or microinverters.

Also, over-simplified advice was to install as many panels as possible, but obviously the ROI diminishes if I make more power than I use vs. paid for. . . Since I don't have an EV yet, and it may be a year or two out, seems like microinverters are more easily added. . .

[subdriver97]

Update:

Re-cap:
- My service panel is rated at 125A degraded to a 100A main breaker. This leaves room for a 25A solar supply breaker. Any solar supply breaker > 25A requires a service panel upgrade.
- SE3800 is the largest size SolarEdge inverter that can be installed on a 25A solar supply breaker SE5000/6000 require 30/35A.
- Service Panel Upgrade price is effectively $1800 (vendor claims $2500, but comparing quotes with and without service panel upgrade reveal $1800)

Here are the options:
1) 4.48kw, 16 LG280 + SE3800 inverter
- No Service Panel Upgrade, add 25A solar supply breaker to existing service panel
- System expansion requires service panel upgrade, additional inverter and min of 8 panels
- System Cost: $15,406 ($3.44/W)

2) 4.48kw, 16 LG280 + M-250 Enphase micro-inverters
- No Service Panel Upgrade, add 25A solar supply breaker to existing service panel
- System expansion requires service panel upgrade, but can add panels/microinverters one by one
- Includes Envoy Comms Gateway & $250 individual panel monitoring fee
- System Cost: $17,163 ($3.83/W)

3) 4.48kw, 16LG280 + SE6000 inverter + Service Panel Upgrade
- System is expansion-ready, can add panels one by one
- System Cost: $17,344 ($3.87/W) - $1,800 service panel = $15,544 $3.47/W

It looks like a no brainer between option 2 & 3. However, the difference between option 1 and option 3 will be the cost to expand the system. If I expanded it would be to support an EV so probably 5-8 panels. The difference is essentially the need to buy a second inverter. I think installation of a second inverter will also require a new permit (where it wouldn't be required to add panels to option 3). I'm thinking I'm saving ~$700 by going with LG280 vs. LG300, I should just put that toward the service panel and do option 3.... About 5 years down the road I'm thinking of putting a pool in so I will probably have to upgrade the service panel anyway (right?).

I'm torn, opinions?

[bcroe]

About 5 years down the road I'm thinking of putting a pool in so I will
probably have to upgrade the service panel anyway (right?). I'm torn, opinions?

Its pretty hard to do much with a 100A panel. Here the question would be, upgrade
the panel to 200A, or something larger? Maybe with a separate panel for the solar?

Bruce Roe

[subdriver97]

Its pretty hard to do much with a 100A panel. Here the question would be, upgrade
the panel to 200A, or something larger? Maybe with a separate panel for the solar?

Bruce Roe

It would be an upgrade to a 200A panel most likely. Hopefully the existing power line from the street can handle this.

Rob

[thejq]

It would be an upgrade to a 200A panel most likely. Hopefully the existing power line from the street can handle this.

Rob

Yeah I think that's the right decision considering you plan to do it any way later. You should confirm with the city about the wiring from the sheet.

[bcroe]

It would be an upgrade to a 200A panel most likely.
Hopefully the existing power line from the street can handle this. Rob

You might need new wire all the way to the pole. But with a line tap to another PV
distribution panel would mean you could run about anything for solar. Bruce Roe

[J.P.M.]

Update:

Re-cap:
- My service panel is rated at 125A degraded to a 100A main breaker. This leaves room for a 25A solar supply breaker. Any solar supply breaker > 25A requires a service panel upgrade.
- SE3800 is the largest size SolarEdge inverter that can be installed on a 25A solar supply breaker SE5000/6000 require 30/35A.
- Service Panel Upgrade price is effectively $1800 (vendor claims $2500, but comparing quotes with and without service panel upgrade reveal $1800)

Here are the options:
1) 4.48kw, 16 LG280 + SE3800 inverter
- No Service Panel Upgrade, add 25A solar supply breaker to existing service panel
- System expansion requires service panel upgrade, additional inverter and min of 8 panels
- System Cost: $15,406 ($3.44/W)

2) 4.48kw, 16 LG280 + M-250 Enphase micro-inverters
- No Service Panel Upgrade, add 25A solar supply breaker to existing service panel
- System expansion requires service panel upgrade, but can add panels/microinverters one by one
- Includes Envoy Comms Gateway & $250 individual panel monitoring fee
- System Cost: $17,163 ($3.83/W)

3) 4.48kw, 16LG280 + SE6000 inverter + Service Panel Upgrade
- System is expansion-ready, can add panels one by one
- System Cost: $17,344 ($3.87/W) - $1,800 service panel = $15,544 $3.47/W

It looks like a no brainer between option 2 & 3. However, the difference between option 1 and option 3 will be the cost to expand the system. If I expanded it would be to support an EV so probably 5-8 panels. The difference is essentially the need to buy a second inverter. I think installation of a second inverter will also require a new permit (where it wouldn't be required to add panels to option 3). I'm thinking I'm saving ~$700 by going with LG280 vs. LG300, I should just put that toward the service panel and do option 3.... About 5 years down the road I'm thinking of putting a pool in so I will probably have to upgrade the service panel anyway (right?).

I'm torn, opinions?

Not to muddy the waters, but there is the considerations of what SDG & E will allow you in terms of system expansion and still allow net metering under the current or new NEM tariffs, depending on the size of the expansion and when it's done relative to AB 327 mandated tariff changes.

[subdriver97]

Not to muddy the waters, but there is the considerations of what SDG & E will allow you in terms of system expansion and still allow net metering under the current or new NEM tariffs, depending on the size of the expansion and when it's done relative to AB 327 mandated tariff changes.

That's a good point, but I'm going to run into that if I ever decide to expand my system. Assuming I want to add 8 panels to support a EV, is there a plausible tariff scenario in which switching from a 4.5 kW system on net metering to a 6.9 kW on tariff would be insufficiently beneficial that I wouldn't want to upgrade? Or is it impossible to know?

$1800 is close more than 10% of the system price so it's definitely something to ponder. Maybe the best thing is to just do the SE3800 for now and see how things play out with AB 327 before deciding if I want to expand. It's plausible that I could upgrade to a SE5000 or 6000 and sell my used SE3800. It may also end up being 10 years before I upgrade and nearing the time that the inverter would be toward end of life. (However, the fact that SolarEdge offers a warranty extension makes me think that these units are engineered to last 20-25 years and very well last that long. Someone mentioned that part of the reason SolarEdge's warranty is limited to 10 years is primarily based on the cash reserves that they need to offer it.

[sensij]

Not to muddy the waters, but there is the considerations of what SDG & E will allow you in terms of system expansion and still allow net metering under the current or new NEM tariffs, depending on the size of the expansion and when it's done relative to AB 327 mandated tariff changes.

Anticipating what PV technology will look like 5 years from now seems hard to do. 5 years ago, the Enphase M190 was just getting launched, SolarEdge just started mass production, and 200 W panels were hitting the market. "Smart" inverters are still in the definition stage today, but 5 years from now? On the other hand, what happens when the tax credit expires.. will manufacturing and supply chain costs drop enough to maintain momentum?

My opinion is to spend only what you need to today. If you need capacity in the future, buy it then. Today's tech should be much cheaper, and tomorrow's tech will be much better. Buy the smaller system today, and work on getting a very good understanding of your usage patterns. Maybe it will turn out that a TOU plan will cover the EV, should that come to pass. If you install a pool, let the panel upgrade be part of the pool cost, don't pay it now with today's dollars just because you can. Spend that $700 on LED's, or better attic insulation, or some other efficiency upgrade that will really help lower consumption.

It might turn out that the successor tariff to net metering makes expanding the system beyond 10% uneconomical. I don't think paying an electricity bill on that additional consumption is the worst possible outcome here. It is hard enough to be sure that today's PV system is economical in today's assumptions.

So, if it isn't clear, I would choose option 1. Same amount of power for the least amount of money. If you need a panel upgrade in the future, you could take some time to shop it on its own, and that will help avoid the fuzziness in pricing that occurs when lots of things get bundled together.

[subdriver97]

Anticipating what PV technology will look like 5 years from now seems hard to do. 5 years ago, the Enphase M190 was just getting launched, SolarEdge just started mass production, and 200 W panels were hitting the market. "Smart" inverters are still in the definition stage today, but 5 years from now? On the other hand, what happens when the tax credit expires.. will manufacturing and supply chain costs drop enough to maintain momentum?

My opinion is to spend only what you need to today. If you need capacity in the future, buy it then. Today's tech should be much cheaper, and tomorrow's tech will be much better. Buy the smaller system today, and work on getting a very good understanding of your usage patterns. Maybe it will turn out that a TOU plan will cover the EV, should that come to pass. If you install a pool, let the panel upgrade be part of the pool cost, don't pay it now with today's dollars just because you can. Spend that $700 on LED's, or better attic insulation, or some other efficiency upgrade that will really help lower consumption.

It might turn out that the successor tariff to net metering makes expanding the system beyond 10% uneconomical. I don't think paying an electricity bill on that additional consumption is the worst possible outcome here. It is hard enough to be sure that today's PV system is economical in today's assumptions.

So, if it isn't clear, I would choose option 1. Same amount of power for the least amount of money. If you need a panel upgrade in the future, you could take some time to shop it on its own, and that will help avoid the fuzziness in pricing that occurs when lots of things get bundled together.

Sounds counsel (and easy on the pocketbook...) Much Appreciated.

[J.P.M.]

That's a good point, but I'm going to run into that if I ever decide to expand my system. Assuming I want to add 8 panels to support a EV, is there a plausible tariff scenario in which switching from a 4.5 kW system on net metering to a 6.9 kW on tariff would be insufficiently beneficial that I wouldn't want to upgrade? Or is it impossible to know?

$1800 is close more than 10% of the system price so it's definitely something to ponder. Maybe the best thing is to just do the SE3800 for now and see how things play out with AB 327 before deciding if I want to expand. It's plausible that I could upgrade to a SE5000 or 6000 and sell my used SE3800. It may also end up being 10 years before I upgrade and nearing the time that the inverter would be toward end of life. (However, the fact that SolarEdge offers a warranty extension makes me think that these units are engineered to last 20-25 years and very well last that long. Someone mentioned that part of the reason SolarEdge's warranty is limited to 10 years is primarily based on the cash reserves that they need to offer it.

I'm not sure it's possible to know, but once you pull the trigger on the 4.5 kW or any other size system now, as things stand at this point, your stuck w/ SDG & E limitations on system expansion under current rules or stuck with new rules if the system is expanded under the new rules, whatever and whenever those become reality. I'm not suggesting it's necessarily cost effective, but it may be a consideration to up the size now, depending on how certain your plans are re electric vehicles, etc.