Planning a solar system. Have some questions.

System · March 2011

Hello to all.
Been studying here for a long time.
Getting ready to install a grid-tied solar system late this summer in western Arkansas. Probably around 3 kW in size to start and would like to have the ability to add more in the future.
Going to mount the panels in the pasture on top of poles near the house. No shading issues to worry about.
Going to try and do a lot of the work myself (digging the holes, bolting everything together).
I have a buddy who is a master electrician. I'm hoping he can wire everything up.

I've been taking in so much information that it's kind of all running together, but I believe I read that there is an adjustable mount to adjust for the angle of the sun at different times of the year. Could someone explain how this works?

I also read a thread about micro-inverters vs. one main inverter and kind of got a bit more confused. Not that hard to do though.
If I understood it correctly, I will need one micro-inverter for each panel and it will be installed outside with the panel. And if I use one inverter all the panels will be wired into it. From what I gathered, the micro-inverters seem like they would be safer just a little more time consuming to install.
Would someone mind elaborating on the pros and cons of each?
What kind of maintenance is involved with an inverter?

Thanks in advance for any help.

Cariboocoot · March 2011

Re: Planning a solar system. Have some questions.

Oh we've been down this road before. In fact this is the second time just today!

See? Your questions aren't that unusual or off-base.

The micro inverters are one inverter per panel, usually about 200 Watts each. Basically the panel's leads plug in to the inverter and the majority of the wiring is on the AC side. This makes for a fairly easy install. Safer? Not necessarily. Some people are just afraid of High Voltage DC. High Voltage AC can also kill you, so it's a moot point.

The down side to the micros is that the cost per Watt tends to be higher than with a central inverter. You should get some actual install quotes for your area, or settle on your system size and work it out yourself. Use the PV Watts program to see what sort of harvest/return you can expect where you are: http://www.nrel.gov/rredc/pvwatts/

As for tilting panels, check out the difference changing angles will make for you using PV Watts and the Mac's Lab optimum angle calculator: http://www.macslab.com/optsolar.html
Basically, the closer to the equator the less gain you get from climbing on the roof and pulling bolts to crank the legs up/down up to four times per year. The other choice is using automatic tracking like this:
http://www.solar-electric.com/zotrmoforsoe.html Single axis trackers follow the sun through the day, dual axis trackers do that and adjust angle for time of year.

mike95490 · March 2011

Re: Planning a solar system. Have some questions.

charlesldii wrote: »

.... What kind of maintenance is involved with an inverter? ...

Keep most of the dust and leaves off it, keep critters from nesting in it. Monitor it's output (check into what software, adapters, dongles, computer, annual subscriptions....) somehow so you know it's really working. They are mostly pretty simple, much like a garbage disposal. Generally good for 10 years or so...

Planning a solar system. Have some questions.

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