Good equipment match up?

[sunpoweredev]

We are close to picking an installer on our grid tied PV system. Most likely going with 36 Panasonic 330W panels (~12kW). The installer selected SolarEdge SE11400H-US inverter with P400 optimizers. Looking at the spec sheets, looks like the installer over-spec'ed the inverter and optimizers a bit which should be a good thing, right?

I'd appreciate any input on this combination of equipment setup. Many thanks.

[ButchDeal]

He p400 is the exect recomended model for the 96 cell panasonic pv modules.
the SE11400 is Perfectly sized for an 11.88kw system.

[sunpoweredev]

ButchDeal thanks for confirming. Mainly wanted to make sure it's not undersized.

Oops typo above. 37 panels, not 36.

[JSchnee21]

Hi sunpoweredev ,

Yes, I also have 37 Panasonic 330W panels with a 11.4kW SE Inverter w/P400 optimizers. As Butch said, this is the perfect setup. I have the older "A-series" inverter. Your newer "H-Series" inverter is smaller and slightly more efficient.

In terms of the cost of my roof. It's two large flat surfaces -- so about as simple as you can get from a labor perspective. With mid grade architectural shingles and two replacement skylights (small) the total roofing cost was ~$8000 ($1200 of this was the skylights). This ranged from $6000-$9000 depending on the grade of shingles.

I bundled this through GPE with (from A&M) with my solar purchase and was able to claim the entire project (roofing and solar) when applying for the 30% federal tax credit. Site prep is an approved cost associated with this refund.

If your roof is already 15yrs old -- assuming you have generic or builder grade asphalt shingles (as I did -- aka crap) you'd definitely want to replace the roof now. Even if they were decent shingles at the time, the tar starts to break down after 15-20yrs. The solar, properly maintained, will last for 30yrs or more.

If you do have the roof replaced, try to allow one to two weeks of full sun between the roof install and solar install to allow time for the tar on the back of the shingles to seal. As others have said (I forget where it was JPM or BCROE) there are other more roofing friendly, flanged anchors which can be used instead of generic L-brackets. You might ask your installer and roofers about these. But it will cost more.

-Jonathan

[sunpoweredev]

JSchnee21 I see bits of my roof coming down from my gutter after a big rain. Oh yeah builder's special shingles for sure lol.

Before your suggestion, in my mind I was looking for every reason *not* to replace the roof, even though knowingly this roof is likely not going to hold up. We actually lost a few shingles from hurricane Sandy, and a few more here and there.

One of the reasons I wanted to avoid doing the roof is to avoid dealing with roofers. When Sandy hit, couple of companies wanted $5000 to replace less than 1 bag's worth of shingles. I actually paid them $500 to tarp up that portion of the roof per my home insurance. Fortunately I had a handyman in the neighborhood that fixed it for $300. Too bad he moved away. The second time a few shingles flew off, another roofing company wanted $1200 to fix.

Thanks a bunch for the info and suggestion. I will definitely look into doing the roof at the same time. No doubt it will save me thousands, especially now that I have an idea as to the cost.

[JSchnee21]

Understood. We were very fortunate with Sandy. Only minor fence damage and a few tree limbs, though we were without power for 10 days -- though this was mostly due to a political squabble between the electric company, the tree removal company, and the township.

In the NJ market, I've used John Asch for a couple different roofing jobs (prior to this re-roof with A&M) and I've been very pleased with them (www dot aschroofing dot com). I had John Asch replace a 10' x 10' section of roof replaced when I first moved into my home in 2006 along with several pipe boots/flanges, and a new skylight in total for ~$1200. The seem very competent / experiences and fairly priced. Probably not the cheapest, but a good value.

I find Angie's List to be a really good resource for:
Finding reputable, busy vendors
Estimating job costs
Getting personal reviews

My impression is that the pricing I got from A&M was below market -- or near the bottom of the market in terms of pricing. But I didn't get competitive bids so I don't know. My in-laws got a new roof in PA a couple years ago, and it was quite a bit more (~$12-16k) but their roof is larger, much more complicated than mine, and has a few more (and larger) skylights.

As a rough rule of thumb, in the 13 yrs I've lived in NJ, most residential building trades seemed to be priced at approximately $1200 per person per day. Plumbing, Electrical, Decking, Roofing, Sprinklers, Windows / Doors, insulation and Energy Star, tree removal. Sometimes a little less, but it usually gets me within 10-30% and prevents surprises.

For A&M they had 5 or 6 guys (if I recall correctly 4 or 5 laborers and a foreman) and they were there for about 5 or 6 hours (e.g. one job per day). So that's inline with historical expectations -- but a bit low given that the materials are fairly expensive (shingles, sky lights). In general, $150 per hour -- roughly half for the trades-person and half for the shop -- is pretty typical.

-Jonathan

[sunpoweredev]

We were out for only 5 days and still had hot water so we were quite fortunate. I kept my aquarium fish alive by filling thermos containers with hot water lol.

Every contractor I've ever dealt with tried to rob me. Central AC went out, one wanted $7k to replace the compressor. It was fixed for $150 with sealant. Furnace draft inducer fan went out, another company wanted $900 to replace. Bought the fan for $150 and DIY in 10 minutes. And the roof repairs mentioned above. Just goes on and on.

Thanks again for all the info you provided. It is extremely helpful.

[motorcyclemikie]

Every contractor I've ever dealt with tried to rob me. Central AC went out, one wanted $7k to replace the compressor. It was fixed for $150 with sealant. Furnace draft inducer fan went out, another company wanted $900 to replace. Bought the fan for $150 and DIY in 10 minutes. And the roof repairs mentioned above. Just goes on and on.

We get "okie doked" a lot where I live also, it more or less becomes a conscientious involvement to get anything accomplished by contractors, so we DIY as much as possible. I don't believe that the solar contractors are the sole exception.
I don't always agree with the reasoning in this forum (it's a forum), however my roof needs replacement before I install my PV system and I fully appreciate the knowledge and experience to be found here by everyone. My brother recently bought ribbed metal roofing and had his $12hr guys install it. It worked out for him, so I am thinking of the same route. Where we live nobody gets permits for repairs or upgrades, but going grid tie changes that picture. I would hate to have a new roof that didn't match code for the PV installation.

[JSchnee21]

sunpoweredev ,

You might take a look at the PSE&G Worry Free contracts if you have them for either gas or electric. I have JCP&L for electric but PSE&G for gas. It's fairly pricey ($44/mo) but i have coverage for my furnace, AC, hot water heater, gas drier, piping, and one or two other things. If you only cover 1 or 2 things it is less.

There are EXCLUSIONS -- Most notably Freon. and AC compressors (I believe it may cover labor just not the part -- not sure -- maybe not at all). BUT I've had several furnace and hot water draft induction fans replaced, as well as most of the guts of my hot water heater, an air handler blower fan, and two starting capacitors for my condensor. All for "free". And the Freon charge to top off my aging HVAC (1997) has only ever been $50-150 and the service call itself is free. And the techs that come are very experienced.

There can be a delay when scheduling, but they do prioritize no heat no cooling calls from a life safety perspective. They do install new equipment. But, the hot water heater I had them install when I moved in seemed very expensive.

-Jonathan

[PAS1949]

I have purchased four 100 watt solar panels. Each has a 8.5 amp charge controller. I have a 400 watt inverter. I need to purchase batteries. I have 9 electric snow melting mats which total 14.5 amps. One mat is 3.5 amps. Three mats are 7.5 amps (2.5 amps each). Five mats are 3.5 amps (.7 amp each). How should I set up my system? Do I need to combine panels? Is my inverter large enough? I would like to get two or three nights from stored power. Thank you your assistance. PAS

[bcroe]

Why do you need an inverter, do the mats operate on 120V? If they do, 14.5A X 120V = 1740W, which is
way beyond your equipment capabilities. Bruce Roe

[PAS1949]

OK! If I start with one mat which is 3.5 amps, would my 4 panels work or should I have 5? And how many batteries are required? PAS

[bcroe]

ok! If i start with one mat which is 3.5 amps, would my 4 panels work or should i have 5? And how many batteries are required? Pas

DO the MATS OPERATE ON 120V?

[PAS1949]

Yes!

[bcroe]

You cannot compare amps at different operating voltages. Multiply the A X V to get watts in each case,
and compare those. 400 watts of panels will not operate 1740 watts of load (mats) directly. To work
time into the picture, multiply watts by hours to get watt hours. Bruce Roe