New member looking for feedback - Inland San Diego County

[CharlieEscCA]

I have been considering solar for a long time, but finally have decided to move forward.

Here are the relevant details:

- Purchase, not lease.
- SDGE crazy rates make solar almost a no brainer.
- Been in my house 25+ years and plan to stay here for another 10 years or more
- Lot's of eucalyptus trees make roof a no go, but I'm on a one acre lot so I've got land for a ground mount
- Annual usage is about 10000 kWH, but this is with limiting A/C to worse days of the year, and then setting to about 81 degrees (open concept house with ceilings as high as 24').Monthly usage is typically 775 to 800 when no A/C.
- Despite 1 acre lot, there still will be shade issues. A large local company with initials BE came out this week and using some hand held meter did measurements and said with shading I would be at 84% (vs 100% with no shading) where as the model they ran before coming out was at 91% (it was a pretty cool software package that they put in my trees and actually sited the install location onto the Google earth map views.
- Using their model, a 22 panel 320w LG system @91% shading with a SolarEdge 7600 inverter was going to yield about 10900 kWH.
- If I do go solar, I absolutely want to upsize as to make my wife happier (and thus my life better), A/C would definately be run on more days, so I'm thinking even a 24 x 310w or 28 x 310w might be in order (more on this in a bit)
- 200 amp main panel (at garage) with plenty of breaker room, and 150 amp service at 200 amp rated breaker in house fed by 150 amp breaker from main panel.

I've got two ways I'm considering to go.

One is at $3.40 per watt using BE with me doing the trenching (add $4000 for them to do the trenching, they really don't want to do it and say I can likely get it done for $700 to $100).

The second is to do a homeowner permitted project with me being the general contractor and using hired help (referred to me by a friend at work) for installation assistance that would come in at $3.00 per watt all installed -- this install would be LG 310 / Enphase M250 (yeah it might clip a bit, but PVWatt showed a whopping 5 KW hours for the entire annual production) -- and this installation would have a trench run about 100' less to the corner of my house where it would then continue in the fully accessable crawl space (varies from 3' to 8' high due to post and beam construction on a lot that slopes back of house to front) to the 200 amp rated panel with room for two 20 amp breakers (to support two strings of the M250).

I like the idea of a shorter trench run, and while maybe SolarEdge might be a little better production wise then Enphase (though it seems you can find studies that go both ways), it seems like the SolarEdge is a single point of failure that would take the entire system offline.

So looking for any feedback / comments / concerns, but a couple of specific questions:

Is it correct that code allows the two 20 amp breakers at the subpanel? When I brought up the "20%" rule I thought applied to the 150 amp breaker to the subpanel, I was told that it was 20% of the bus rating and the subpanel bus was rated for 200 amps, so it would be ok.

What's the deal with the Siemans / Enphase relationship? The Enphase warranty is from Siemans, and Siemans has their own M250 -- is it the same or different than Enphase? I'm thinking it's slightly different -- after all the Siemans spec sheets says up to 310 watt STC input, where the Enphase recommends only 300 watt (though I'm ok with the 310/M250 pairing based on all that I've read).

Thanks in advance for any comments, and for this great site!

[Mike90250]

Run the calcs for the wire size, 8Kw @ 240VAC will need larger wire than 8Kw @ 420VDC to a string inverter,

I think the microinverters will have overvoltage issues, from the long run from the array, to your 150A service run, At least they will be easy to replace failed ones.
A string inverter saves at least the distance from array to service panel.

There have been several members with AC high voltage issues, more with micros than string inverters

[J.P.M.]

Baker's a good outfit, and $3.40/Watt for a ground mount, the price is probably not too bad for around here - even with trenching ( I may be one of your neighbors - zip 92026, east of the 15, up the hill behind the Welk resort ).

I don't recommend vendors and this ain't a plug, but I doubt you can do as good a job yourself as they can do. Just make sure you/they get the AHJ involved ASAP.

But, sometimes Baker needs a push on price. They're tough on negotiations and won't usually budge too much on price (but some if you use a cattle prod). I'd get a quote or two for comparison. Sullivan will be higher, Milholland may be a bit lower than Baker but both may balk/decline a ground mount. Don't share prices with vendors - you'll only pay more. IMO, They're probably 3 of the best vendors around.

Whoever you buy the equipment from, one thing to check: LOOK at the panels that get delivered to the site and MAKE SURE they are the same STC Wattage as the contract reads and what you think you're buying. Once in a while vendors will skunk in older panels of the same physical size of the same company mfg., but lower Wattage - perhaps another side benefit of underestimating performance - which is common. Doesn't happen much, but I've seen it 2X in monitoring about 100+ installs for my HOA. A ground mount will probably make such material subbing less likely.

Ideal array orientation for you will be about 29 deg. tilt, 192 azimuth - for no shading +/- about 5 deg. for both and not super critical. However, your shading will change that ideal orientation. Your unshaded annual output will be about 1,750 kWh/yr. per installed kW. Shading will reduce that - how much ?? I'd cut the trees down.

With a 10 yr. time line, I'm not sure upgrading your A/C will be cost effective, but short of that, any other load reductions via conservation efforts or lifestyle changes will make your proposed system more oversized, which sounds like a goal for this project. Such measures will be a more cost effective way to meet that project goal than increasing the array size.

[philips]

Don't forget to consider how time-of-use (TOU) rates will affect you. Currently they are mostly favorable for solar production, but there is pressure for peak rates to shift to the evening.

I would look into an orientation more south west like J.P.M mentioned (ideal for the current 11-6 or 12-6pm peak??). I haven't ran the numbers for a possible 2-9pm or 4-9pm TOU peak, but it may make sense to have an azimuth more west than 192.

[bcroe]

As was pointed out, it will take A LOT more copper to limit voltage rise using micros, than string inverters. But with
shade issues optimizers might be required. With one acre shade could well be from your neighbors property; harder
to cut down HIS trees. Dodging that shade for all seasons will tend to push the array into a specific area of the lot,
make sure it doesn't interfere with other stuff. I'm tending to optimize for summer KWH; winter production is so
much less here. Bruce Roe

[DanKegel]

Also check how SDGE rates are likely to change, the top tiers are supposedly going to be flattened down a bit statewide (and a new top tier at 4x normal usage added).
See http://www.sdge.com/RateReform/
Might change your payback time.

I suspect the solaredge central inverter's pretty reliable, I wouldn't worry about it being a single point of failure (not that I'd really know; I've only had mine for 9 months or so).

[baadls1]

I just signed a contract with Baker last week and discussed it in this forum. I don't think you will find any better option out there. . I was very impressed with his knowledge and transparency. He made things very comfortable for us. Everyone in my father's neighborhood down in Poway says they do excellent work, and the clients have had pretty high expectations.

[J.P.M.]

For T.O.U. which you will be on, optimum UNSHADED orientation in N.C. Inland San Diego is about 210 azimuth and about 30 deg. tilt. Fortunately, that orientation is not critical. As long as the the tilt lt is somewhere between about 20 deg. and 40 deg. and the azimuth is between 180 and 230 deg. the annual per STC kW production won't be less than about 96 % in terms of revenue or about 94 % in terms of annual production from that of the optimum orientation which, using current SDG & E T.O.U. tariffs and SAM production estimates is $469/yr. per STC kW and 1,784 kWh/yr. per STC kW.

[CharlieEscCA]

It's me again

Apparently mentioning vendors in here is ok.

I just got a quote this week from Cosmic Solar for a system using Q.Plus BFR-G4.1 280 panels with SolarEdge optimizers and SE7600, and ProSolar GroundTrac mounting system -- installed at $3.00 per watt DC. This is significantly lower than Baker, and Baker wanted me to do the trenching.

I see from searching online that the lower price is certainly due to the much lower price of the panels vs LG -- but if I have the space for the size of the system I want, then it seems a watt is a watt.

Any thoughts on these panels or the ground mount system?

And the 1,784 kWh/yr figure per STC kW is good to know, because Cosmic is also offering a written first year production guarantee of 13,431 kWh on this 7.84 kW DC STC system -- recall I will have unavoidable shading unless I wish to chop down trees, which is not happening. If production is below the written guarantee, panel(s) would be added at no expense to me. Given my uncertainty of knowing how bad my shading is or isn't, a written guarantee is viewed as a desirable plus to the quote.

[CharlieEscCA]

I don't recommend vendors and this ain't a plug, but I doubt you can do as good a job yourself as they can do. Just make sure you/they get the AHJ involved ASAP.

...

With a 10 yr. time line, I'm not sure upgrading your A/C will be cost effective, but short of that, any other load reductions via conservation efforts or lifestyle changes will make your proposed system more oversized, which sounds like a goal for this project. Such measures will be a more cost effective way to meet that project goal than increasing the array size.

We are "semi close" neighbors. East of I-15, by Orfilia Winery.

What is AHJ? I've read a lot, but missed that term.

Lifestyle changes / conservation changes have been done -- that reduced usage about 100 to 150 kWh per month.

And after giving it more thought, the current 27 year old house A/C can stay as is until it dies.

But at $3 / STC DC watt, I'm willing to fund oversize to allow greater summer A/C use and if still excess, consider the electric Mini Cooper that's being talked about for 2018/2019 timeframe. I'm on my second Mini Cooper, and I like the car

[J.P.M.]

We are "semi close" neighbors. East of I-15, by Orfilia Winery.

What is AHJ? I've read a lot, but missed that term.

Lifestyle changes / conservation changes have been done -- that reduced usage about 100 to 150 kWh per month.

And after giving it more thought, the current 27 year old house A/C can stay as is until it dies.

But at $3 / STC DC watt, I'm willing to fund oversize to allow greater summer A/C use and if still excess, consider the electric Mini Cooper that's being talked about for 2018/2019 timeframe. I'm on my second Mini Cooper, and I like the car

Thanx for the info.

AHJ == "Authority Having Jurisdiction" - In effect the county building inspector. The outfit that reviews submitted plans, issues permits and inspects the work. If used as a resource, they can be most helpful. Go at them with an attitude and you'll probably regret it. Don't be afraid to challenge them if you think you're right, just be sure of your case and be professional about it. You'll get more flies with honey than vinegar. Besides, their guns are bigger and they have more rounds than you.

At ~ 10,000 kWhr./yr. you've done much to conserve.

For your time frame of ~ 10 yrs., I'm not sure spending several thousands of $$'s to save maybe a couple hundred/yr. is cost effective. On the other hand, if you use it more because your bill goes down as a result of PV, the annual savings from a changeout would be a bit more. I'd get the existing unit checked in the spring and maybe do some homework on new units. Just don't oversize. That's usually counterproductive as oversized unit's cycle time is lower. that usually means, among other things that humidity levels in the dwelling can be higher than with smaller units. The result is a damp, clammy house.

EV's are in my future as well - maybe - but my guess is probably 3 or so years from now, maybe more. another guess - I'm thinking I'll be able to wring about 3.5 miles out of every kWh in a vehicle battery. FWIW, my ex. has a Mini and swears by it. Not an endorsement (of the vehicle - the ex can speak for herself. )

Bet you're on the other side of the road from the winery ? No ID's. Just guessing.