Getting solar on our garage

[Tithis]

So early last month we had a salesmen from Trinity solar approach us about having them install solar and entering a purchasing agreement with them. We quickly shotdown anything but financing them and over the last few weeks have been working with them and a couple other installers on getting some quotes together for us.

Now our house is 250 years old and our rafters are literally logs with the bark still on them, so we're reluctant to add additional unneeded weight with solar panels, so instead we are planning to have the panels installed on a detached garage built in the 90s. Its a ~24x24 garage with a ~10/12 roof facing almost straight south (~172 degrees)

Initial quotes we've received.

Trinity Solar
System Size: 4.8KW
Panel: 12x400w Hanwha Q Cells
Inverter: Solar Edge Optimizer

Cash Cost: $26,544


New England Clean Energy
System Size: 4.8KW
Panel: 12x400w Hanwha Q Cells
Inverter: Enphase IQ8Plus MicroInverter

Cash Cost: $22,272


AllEnergy Solar
System Size: 5.74KW
Panel: 14x410w REC
Inverter: Enphase IQ8Plus MicroInverter

Cash Cost: $26,209


Right off the bat Trinity was pretty much out of the running due to being the most expensive, and they were fully removed when we discussed AllEnergy being able to fit almost another full kw on the roof due to their panels being both higher wattage and their narrower size allowing two extra panels. Their only response was for me to consider their warranties and how long they've been in business. You guys helped sell on getting solar... just not your solar.

When I reached out to New England Clean Energy they said they mentioned they offered the REC panels if I wanted to squeeze some more wattage out of the roof space, but they only mentioned the increased panel wattage and nothing about the possibility of fitting two extra panels on the roof. Kind of an important detail guys... Currently they are working on a 2nd quote with the REC panels.

Hoping to make a final decision later the week once we have the new quote for New England Clean Energy. Surprised that the panels being 1.1 inches narrower is making the difference here.

 

[stoveliker]

I don't know what the current market is, but I got 7.2 kW for $22,391 - back in 2018. (I have Enphase IQ7+ microinverters, and LG360 NeON-R panels.)
Costs have gone up this much?

 

[Tithis]

I am actually going back to AllEnergy Solar about their quote while I'm waiting for New England Clean Energy.

They provided an initial/preliminary whatever quote on Energysage for the project that is dramatically cheaper than the one they provided via email. Their initial quote was $19,188 for 12 of the same REC panels and higher capacity IQ8-A microinverters. Really just straight up asking why the price per watt went from 3.90 to 4.56 when I'm getting lower capacity inverters and if there is some challenge to the install that explains that kind of price increase. If they were consistant with price/watt the quote should have been about $4,000 cheaper.

 

[peakbagger]

Unless you have shading issues your installers are missing something. On a garage, unless its local code, you do not need rapid shutdown capability, therefore you can go with single string inverter with dual (or more ) Mppt inputs. This also keep electronics off the roof as the string inverter can be mounted in nice cool shady spot for longer potential life. A single string inverter generally costs less. The referenced Solar Edge inverter usually is paired up with panel level optimizers. Nice if you have shading issues but adds cost and you have electronics baking under the panels. The trade off is you lose panel level monitoring available with optimizers or microinverters and you lose some output if you have shading issues which any good installer should be able to model. Setting up the strings correctly with string inverter can help avoid shading by breaking the strings up correctly but no where near as well s microinverters.

Home run wiring from the panel to inverter is lower as you are moving higher voltage DC so slightly smaller cables.

 

[Tithis]

We do have shading issues. I knew that going in and wanted microinverters for that reason.

 

[peakbagger]

That is rather key issue that you skipped on your original post. Sounds like you have a handle on it, good luck with the project.

 

[Tithis]

Yeah, trying to get a third quote to match the AllEnergy Solar people. They answered my question on the large price jump and justified it with needing to come out for 2 days for a 14 panel install vs 1 day for a 12 panel, and the steepness of the roof meaning they will have to work slower.

Had a call with a local place I looked up that underwrites with my fiances radio station. Guy said he was confident on a price of around $20,500 for 14x400watt REC panels (so 5.6kw system vs 5.74kw) and doubted it would vary more than 500 bucks or so. Gonna have a followup meeting with them tomorrow on it.

 

[Tithis]

Definitely looking like we'll be going with Valley Solar.

System Size: 6.8KW
Panel: 17x400w REC
Inverter: Enphase IQ8Plus MicroInverter

Cash Cost: $24,888

Like AllEnergy Solar they are 2 rows of 7 panels in portrait, but additionally are going to put 3 panels in landscape near the ridge of the roof. This would cover 80-90% of our electricity and so far has the cheapest $/watt at $3.66.

From our discussion the only things that should affect that price as this point is if need to upgrade our electrical service or panels or service. From what I've researched would should be fine though as the garage sub panel has 125 amp rated bus bars and a 50 amp breaker to the house, and the main breaker has 150 amp rated busbars and has a 100 amp breaker for our service.

They also said if I tell them I want a battery backup in the future they would swap over to a SolarEdge Inverter with optimizers for $1000 extra. Good chance I'll take them up on it as that is something my wife really wants one day.

 

[DBoon]

if I tell them I want a battery backup in the future

Is the garage heated? Just make sure that any thought on putting a battery in the garage match what environmental conditions the battery requires. It would be great to have the battery in the garage - not the house (reduced house fire risk). Lithium Ferrous Phosphate is a better choice for home battery backup due to reduced fire risk (my opinion).

 

[Tithis]

Garage is currently unheated, although I would like to eventually put in a dual zone mini-split with one head in the FROG and one in the garage proper. Wouldn't expect the garage one actually heat it in winter, just enough to take worst of the chill off if I have to do some car work in winter.

Anyways we are still going forward with Valley Solar, cost went up ~$1k for the final plan. They are going to bring in a trencher to run another conduit between the house and garage. Frankly I'm not sure why as the existing circuit going to the garage should be sufficient enough as is, and the conduit is big enough where they could rerun the line with a high capacity one, something I might do anyways for the mini-split and any future car chargers. Best guess is they want to have the disconnect by the meter for safety.

Current plan is for everything to be installed in spring.

 

[peakbagger]

Definitely looking like we'll be going with Valley Solar.

System Size: 6.8KW
Panel: 17x400w REC
Inverter: Enphase IQ8Plus MicroInverter

Cash Cost: $24,888

Like AllEnergy Solar they are 2 rows of 7 panels in portrait, but additionally are going to put 3 panels in landscape near the ridge of the roof. This would cover 80-90% of our electricity and so far has the cheapest $/watt at $3.66.

From our discussion the only things that should affect that price as this point is if need to upgrade our electrical service or panels or service. From what I've researched would should be fine though as the garage sub panel has 125 amp rated bus bars and a 50 amp breaker to the house, and the main breaker has 150 amp rated busbars and has a 100 amp breaker for our service.

They also said if I tell them I want a battery backup in the future they would swap over to a SolarEdge Inverter with optimizers for $1000 extra. Good chance I'll take them up on it as that is something my wife really wants one day.

Mass really wants you to have a battery, the claim that I have not verified is that with incentives and revenue the battery will be paid for in 5 years. Here is link to the NGRID program https://www.nationalgridus.com/MA-Home/Connected-Solutions/BatteryProgram

 

[Tithis]

Got out system installed back in April, and it finally was turned on last week.


We ended up going back to them challenging the idea that we needed another conduit when we both have an existing one with plenty of room for more conductors and that the garage has its own sub-panel with 50amp connection to the house. They never really got back to us on it, but when the electricity came the 2nd day he asked to see the garage subpanel and wired it like this.


Supposedly called a feeder tap and looks like it just shares existing garage circuit. Was nice to get the $500 trench fee back.

I am somewhat wishing I tried to push for higher rated inverters, the clipping makes me sad



Finally we did have one issue with Valley Solar. I initially signed the agreement in November, but had to resign it in February to put my fiance on it since the financing is under her name. I guess during that time the company switched from a 15 year workmanship warranty to 10 year, and they changed it on the agreement without telling us. I caught it a few weeks before the install and was kind of a pain to get resolved. The VP of sales needed to approve it and he was completely unresponsive to emails or his own employees on the matter. It wasn't until I dug up his cell phone on a 3rd party site and called him did I get any traction.

 

[begreen]

We get clipping too, but the inverter was a good deal at the time and has performed well. Enjoy the solar watts.

 

[bogieb]

Got out system installed back in April, and it finally was turned on last week.
View attachment 312827

We ended up going back to them challenging the idea that we needed another conduit when we both have an existing one with plenty of room for more conductors and that the garage has its own sub-panel with 50amp connection to the house. They never really got back to us on it, but when the electricity came the 2nd day he asked to see the garage subpanel and wired it like this.

View attachment 312828
Supposedly called a feeder tap and looks like it just shares existing garage circuit. Was nice to get the $500 trench fee back.

I am somewhat wishing I tried to push for higher rated inverters, the clipping makes me sad

View attachment 312830

Finally we did have one issue with Valley Solar. I initially signed the agreement in November, but had to resign it in February to put my fiance on it since the financing is under her name. I guess during that time the company switched from a 15 year workmanship warranty to 10 year, and they changed it on the agreement without telling us. I caught it a few weeks before the install and was kind of a pain to get resolved. The VP of sales needed to approve it and he was completely unresponsive to emails or his own employees on the matter. It wasn't until I dug up his cell phone on a 3rd party site and called him did I get any traction.

That is interesting on the workmanship warranty. I wonder what happened that made them lower it. It could just be an insurance thing, or it could be a rash of failures between 10 and 15 years (I'm assuming they've been in business that long).

 

[bogieb]

I probably will never see clipping. Not that it won't happen, I just won't be able to tell for sure - who knows, maybe there will be a tell-tale that I'll recognize once I get more time understanding the usage charts. I have a hip roof so have panels on 3 sides. I have some shade on the east and south sides, so need the micro inverters there. The west side has no shade. Oh, now that I think about it, with the snow we get, I'd have to have microinverters regardless. I had plenty of days only portions of panels had cleared off and they still produced while the other panels were completely dark.

 

[peakbagger]

That is interesting on the workmanship warranty. I wonder what happened that made them lower it. It could just be an insurance thing, or it could be a rash of failures between 10 and 15 years (I'm assuming they've been in business that long).

IMHO, the only difference 10 to 15 years on workmanship would really impact is roof leaks and material corrosion.

 

[bogieb]

IMHO, the only difference 10 to 15 years on workmanship would really impact is roof leaks and material corrosion.

That is probably true.