malakim_angel209 karma2013-03-23 16:52:51 UTC
if you wire an array in series, the voltages add up, and with high voltage you can have smaller wire size to deliver the same power. Wire sizing is dependant on how many amps the wire can carry without compromising the insulation and starting a fire... for instance #10 gauge copper wire can accept over current protection up to 30 amps in the National Electric Code.
If you have 10x200 watt panels, they probably put out around 50 volts and 4 amps each. 1 string of 10 panels will be 500 volts and 4 amps. A parallel array would be 50 volts and 40 amps, so you're going to need much bigger wire and you're going to lose more power to resistance since the volts are low.
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malakim_angel169 karma2013-03-23 16:07:36 UTC
That is a good question. I worked for one solar company that went bankrupt, and many of their customers are now out of luck as far as the installation warranty goes. Some already sold systems were sub-contracted out to other installers to be completed. In this volatile market, you have to beware of offers that seem too good to be true. Those great deals may lead to a company's eventual bankruptcy. I wouldn't trust quotes for less than $3 / watt unless you're getting a large-scale commercial installation quote.
Most panels have a 25 year power production warranty, and a 5-year frame warranty, and the bigger the company the more likely they are to be around to honor that warranty. I like Sunpower, LG, and Kyocera panels. If the installer has NABCEP certified installers, they are more likely to be legitimate and will generally put in a good-quality system. Make sure the installer is a licensed electrical contracter and is insured.
One thing to note is you want your roof to be relatively new since those panels may be up there for 25-50 years. Removing the panels to re-roof is a few grand. Any honest solar salesperson would take the condition of your roof into account and inform you if you should re-roof before installing solar.
You can ask your salesperson if they make a commission on the systems they sell. In my experience, non-commissioned salespeople will put less pressure on you and be more honest with their answers.
malakim_angel95 karma2013-03-23 16:46:05 UTC
I am happy to see people installing solar now, but I fear they may feel short-changed in 10 years when all this amazing technology becomes mass-produced. right now PV efficiencies are around 15-20% for mainstream solar panels. (so if full sunlight hits your roof it is about 1000 Watts or energy/ square meter... resulting in 150-200 Watts of electricity.)
I have read about this possibly tripling in the coming decade. I've been thinking I'd save up for better stuff in the future.
But if people don't buy solar now, there won't be as much financial incentive to come out with more and better solar products. Catch-22 much?
Edit: I've talked to some co-workers, and they feel the next 4 years won't bring as much solar tech improvement as the last 4 years have already given us.
TLDR; Revolutionary technology exists, it just needs funding to be mass-produced.
malakim_angel84 karma2013-03-23 16:36:35 UTC
On the cheap, you could use aluminum L-stock to create roof-attachments that you'd lag-bolt to your rafters through the roof, seal it with silicon sealant. make racking out of same L-stock, use bolts to attach some old solar panels, run #10 USE wire from panels to a fused disconnect, to some cheap charge-controllers, a few batteries, and a crappy 2-plug inverter.
I wouldn't want to run sensitive electronics from such an inverter, but it would be fine for lights, mini-fridge, etc.
you'd need to measure your roof, and get solar panels that would fit.
malakim_angel71 karma2013-03-23 16:18:54 UTC
I was lucky to start in solar in 2006 through a connection with a friend. A willingness to learn and being comfortable with heights was all that was required.
Nowadays, for new hires we generally prefer a renewable energy certificate (2-year or 4-year), general construction experience, or electrical training.
Your renewable technology certificate will definitely get you a leg up on entering the industry! If I were you I'd want to take classes on Geothermal, Solar thermal, and photovoltaic solar. I knew quite a few folks that have had success starting as electrical apprentices and then specializing in solar installation/repair...
I've installed a few wind-turbines, but I don't like them since the wind is so sporadic in Colorado, and the moving parts seem to invite eventual failure. If you were to be somewhere with consistent wind, then studying wind-power installation would be good too.
Jobs available: PV designer, Renewable energy financier, Installer, Electrician, Sales person, marketing, energy auditor, Maintenance/repair guy. I know a friend who is starting his own company just installing animal guard to keep squirrels out from under the arrays.
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