Looking to go solar...everything looking good, am I missing something?

[roxanwright]

I have Bosch 255W panels install since Dec 2103. I don't think they are any different as other brand name (discontinued) and I got them at $2.84 per Watt DC before incentives. I have lots friends looking for the same deal and wish they can get my deal, but no more.

We offer the best

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[josh26757]

Ok so here come the big dogs! I finally got a quote on SunPower panels and inverter, which everyone seems to agree are the best in the industry. They actually quoted me on the largest system yet, 11.2kW, to cover 100% of yearly electricity. I'm waiting to receive the month-by-month production number so I can plug them in and see if it's worth going with a system that big.

11.2kW system producing 21,300 kWh per year
35 x SunPower SPR-320NW-WHT-D 320W panels
1 x SunPower SPR-11401f-i UNI inverter
$43,904 pre-tax credits ($3.92/watt) - $29,732.80 after tax credits ($2.65/watt)

You do get a better "bang for your buck" on these more expensive systems because you get a lot more back tax credit wise. So for example a $44,000 system will end up being $30,000 net, while a $31,000 system would be $21,000 net...so you get $14,000 for $9,000 basically.

One thing I've learned, which I wasn't told of until today, is that these 2.99% financing deals seem to only be available on the higher priced panels (SunPower, SunEdison). The lower priced (Canadian Solar, Hanwha) have a rate of 7.99% so you're getting a lot less for your money, combined with less tax credit, doesn't really seem to make a lot of sense.

I am in a different location, but did a write up on my system at joshuablaylock.com (you can also see the live monitoring). I got a 7.44KWh system after rebates for right at $10,000 and installed it myself. It was really easy and I used Astroenergy/SolarEdge combination with the panels putting out 310 watts each. I also installed a hybrid hot water heater and am using a TED5000 to monitor power usage. I was able to drop my usage at night down by 50% and got my monthly usage from 1600KW to 1024KW. The panels are already running 95% of my usage and I am paying minimum bills. It has been rainy and cloudy quite a bit too, but I am hoping to get a good rise over the summer. This is my first year, but I must say that all the outputs that were listed to me were actually under what I am seeing.

[Ian S]

Yeah that was the idea...that was just showing if how many we could fit if we wanted, but it would probably be an 11kw-12kW system.

Sounds good!

[HX_Guy]

Yeah that was the idea...that was just showing if how many we could fit if we wanted, but it would probably be an 11kw-12kW system.

[Ian S]

I received the Suneye results from one of the installers along with their recommendations for panel placement. We wouldn't actually even need these may as 45 panels would equal 14.72kW using SunPower 327w panels but if we go with a 255w-265w then it would be 11.48kW - 11.93kW. He said they have to figure out how they would string though so these placements aren't final.

The percentages are for annual sun exposure.. What do you guys think? Not as bad as I was fearing?

You really don't want to produce more than you use else you'll be essentially donating the excess to APS shareholders. You should be able to pretty much cover your usage with something around 12-13 kW. Why not nibble away at the partially shaded panels to reduce your overall power to that level?

[HX_Guy]

I received the Suneye results from one of the installers along with their recommendations for panel placement. We wouldn't actually even need these may as 45 panels would equal 14.72kW using SunPower 327w panels but if we go with a 255w-265w then it would be 11.48kW - 11.93kW. He said they have to figure out how they would string though so these placements aren't final.

The percentages are for annual sun exposure.. What do you guys think? Not as bad as I was fearing?

[J.P.M.]

This has to make you question the knowledge and competence of the companies providing the quotes!

Caveat Emptor.

[russ]

This has to make you question the knowledge and competence of the companies providing the quotes!

[silversaver]

Yeah all the quotes were for 1 inverter, two inverters would
would bump up the price quite a bit. Wouldn't it be easier and make more sense to go micro-inverters.

10kW solar on multi roofs..... no way it can be done on 1 string inverter. I don't think there's a dual MPPT inverter larger than 6kW...

[HX_Guy]

Yeah all the quotes were for 1 inverter, two inverters would
would bump up the price quite a bit. Wouldn't it be easier and make more sense to go micro-inverters.

[fuzzelogic]

Another possibility would be to use 2 inverters. 1 for the large roof and 1 for the other smaller system.

1 - it gives you be better redundancy if 1 of the inverters would have a issue.

2 - It could give more flexibility in not having all the panels tied to 1 inverter.

The catch would be is if you would have enough panels to turn on the smaller inverter...

When looking back at earlier posts, it looked like both quotes only mentioned 1 inverter?

[inetdog]

You definitely do not want to put panels with different facing directions into the same string. It will really reduce your output.

And if you can get the same number of panels (all one direction) into each string, say 1 E string and one S string, then IF neither string has partial shading issues you can combine both strings into one MPPT input with almost no losses at all.

But if the shade is going to be marching across the array during any hour of decent production, you will be better off with either micro inverters or DC optimizers.

[HX_Guy]

One of the companies mentioned the dual MPP thing but they were wanting to put all south facing panels together and then the east facing together (something about 14+14 south facing panels and the remaining east ones on a string). That doesn't seem like it would be ideal to me as then the south facing panels on the north end of the house would be affected if the south side panels are in the shade. Maybe they are putting more importance the rest of the year and not the 3-4 months during winter.

[silversaver]

Well that sucks. I guess micro-inverters would be the better way to go?

You can use the inverter that has dual MPP trackers on the shadow side of panels. Take a look of SMA TL-US series that has OptiTrac (shade management)

http://www.sma-america.com/en_US/products/grid-tied-inverters/sunny-boy/sunny-boy-3000tl-us-4000tl-us-5000tl-us.html

[HX_Guy]

If one panel is affected, the whole strings act the same.

Well that sucks. I guess micro-inverters would be the better way to go?