Advice on a 1.2kw grid tied system

[oliverd]

I live and work at a small nonprofit in central Georgia. We were recently given 4 Schott Solar ASE-300-DGF/50-300 (300W) panels (see image). They are 10 years old, but generated power for only about 5 years. The rest of the time they were in storage. We are fairly handy with building and wiring and have a licensed electrician available. So we're hoping to purchase the balance of system components and self install the panels in a grid-tied system.

After some research, it seemed that my inverter options were limited. None of the micro-inverters I looked at could handle the 60.0 Voc of these old panels and the market for string inverters below 2000 watts seems slim. Three reasonable possibilities emerged: Sunny Boy (1200 or 1700), Kaco blueplanet 1502xi, and Fronius Galvo 1.5. I could not find a Sunny Boy in 60 Hz for a reasonable price, and the Kaco and Fronius were about $1500. This is definitely more than we'd like to spend given we'll also have to buy racking, wiring, etc. If we must bite the bullet and spend the $1500, I'm inclined towards the Kaco because of its two integrated DC and AC disconnects.

I have tested the four panels and all are fully functioning (even though the glass on the back of one of them is cracked). We have sunny space for the panels to ground mount in full sun with no shading issues. Our design low temp is 14F and our design high is 97F.

Any advice you have on setting up this system would help. In particular, affordable inverter suggestions (new or used) would be most welcome.

Thank you,
Oliver

Module specs.jpg

[Amy@altE]

I have good news for you. ABB MICRO-0.3HV-I-OUTD can handle 96 cell panels, up to 79V in. I checked their string sizer tool, it will definitely work with your panels. Especially since you have a damaged panel. I wouldn't invest in a string inverter that needs all of them to work.

4 micro-inverters @ $200 each, 4 connector cable for $100 total, ABB CDD for $300, plus a few random pieces, add another $30. You are under $700, and have the ability to add any other panels you happen upon in the future. Plus racking, wiring, AC disconnect, etc. of course.

Amy

[Amy@altE]

You do want to be realistic about how much power you are going to generate with only 4 panels, figure if it is worth it. 300W x 4 x 4.74 average sun hours x .77 = 4380Wh a day x 30 days = 131kWh a month. Check how much you are paying per kWh, and see what you will save a month. Up here in MA, it's about $0.16 x 131kWh = $21 month.

[oliverd]

I have good news for you. ABB MICRO-0.3HV-I-OUTD can handle 96 cell panels, up to 79V in.

Thanks, Amy. Ok, newbie question: If I count the smaller squares on each module (which I presumed to be one cell each) there are 12 cells x 18 cells = 216 cells. Does that not mean it's a 216 cell panel? Would that micro inverter still work? I tried unsuccessfully to find the Schott ASE-300 on the ABB string sizer tool.

[sensij]

Thanks, Amy. Ok, newbie question: If I count the smaller squares on each module (which I presumed to be one cell each) there are 12 cells x 18 cells = 216 cells. Does that not mean it's a 216 cell panel? Would that micro inverter still work? I tried unsuccessfully to find the Schott ASE-300 on the ABB string sizer tool.

Yes, it is 216 cells. More information on that panel is here. Amy's recommendation is still fine though.. matching the Voc, Vmp, Isc, and Imp to the microinverter is what is important, not the number of cells. The 96 cell style she mentioned is what has become the conventional construction of a panel that has similar electrical characteristics to yours.

[Amy@altE]

Sorry, I hesitated about referring to the cell number, as they have them wired in series and parallel in such a way that it is equal to a 96 cell panel voltage. I caused more confusion than needed, I should have just referred to voltage.

I just took a screen shot of the ABB string sizer, you can see the panel specs match yours.

[oliverd]

Sorry, I hesitated about referring to the cell number, as they have them wired in series and parallel in such a way that it is equal to a 96 cell panel voltage. I caused more confusion than needed, I should have just referred to voltage.

It was going to trip me up at some point, so I'm glad to be educated. And I'm very glad to know I have a significantly less expensive micro inverter option. Thank you!

[SunEagle]

I have good news for you. ABB MICRO-0.3HV-I-OUTD can handle 96 cell panels, up to 79V in. I checked their string sizer tool, it will definitely work with your panels. Especially since you have a damaged panel. I wouldn't invest in a string inverter that needs all of them to work.

4 micro-inverters @ $200 each, 4 connector cable for $100 total, ABB CDD for $300, plus a few random pieces, add another $30. You are under $700, and have the ability to add any other panels you happen upon in the future. Plus racking, wiring, AC disconnect, etc. of course.

Amy

Hmmm. With 4 of those $200 micro inverters plus $100 of cable, a $300 ABB CDD and $30 misc hardware that comes to over $1200 invested. With him saving 131kWh per month or ~$21 he should be able to break even in +5 years or just about the time one or more of those panels stop producing. But it can be a fun project to build and test out.

[Mike90250]

The panel with the cracked glass, is going to very likely fain within 2 years of being exposed to the weather, sorry, just don't count on it lasting very long.