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+--- Thread: Solar Electric Question (/showthread.php?tid=10346)
RE: Solar Electric Question - kalakoa - 09-14-2012
Biggest challenge to a $2500 system is the "island price" for solar panels (and batteries, charge controllers, inverters, etc), and the "fridge premium" if you go with a DC fridge.
With commodity parts and off-island panels, it's possible to design a $2000 system that includes a fridge and water pump. Many of the "expensive" parts are available from Amazon; several eBay vendors offer free shipping on the UniSolar PVL panels (they're flexible, so can be rolled up into a USPS flat-rate box).
I paid under $2/W for my panels, so it was cheaper to install enough wattage to run a dorm fridge ($200, WalMart). Works great, no generator required.
RE: Solar Electric Question - ericlp - 09-14-2012
Hey kalakoa,
Do you have an email address or you can email me @ punaweb@gmail.com. I'd like to see your setup...
Maybe you can send me that PDF.
Thanks!
RE: Solar Electric Question - Cagary - 09-14-2012
quote:
Originally posted by terracore
quote:
Originally posted by GuitarDude
I have been reading through the solar water heater comments on this thread & have a question. Are these systems on properties that are on the grid? If so how much $$ do you estimate that's saved on your helco bill? I hadn't put much thought into a solar hot water system, but this has me thinking. Thx. Steve
The number that is thrown around for "how much do you save" with a solar hot water heater varies so much because hot water usage varies so much by family, but the figure I hear the most is "about a hundred bucks" a month. The "net" cost of installation is about $1,700 after rebates and tax credits, so using the $100 figure it takes less than 2 years for the system to pay for itself and then you've got free hot water for life. Unlike PV (electrical) systems that are always subject to technological breakthroughs that will either dramatically lower cost or raise efficiency, making "is now the right time to buy them" always a gamble, solar hot water heater systems are already as efficient as they need to be (refer to my previous post regarding we never run out of hot water) or are going to get in the near future, so now probably really is the best time to get them while the rebates and tax credits are still in place. Even if you are wrong, by the time that changes it will probably be 2 years from now and your system will already be paid for and you're enjoying free hot water anyway. Depending on who's figures you believe the average electricity bill (with a home with electrical hot water) is between 25-37% used for heating water. Amazing that a $1,700 investment can make that percentage GO AWAY.
Edited to add, we are on the grid.
Isn't there some maintenance and replacement parts involved?
RE: Solar Electric Question - mailes - 09-14-2012
ericlp, I'm assuming ur talking to moi,
Did I say morningstar? My bad!
Here's the system we copied:
http://www.midnitesolar.com/pdfs/Small_DC_MPPT_system.pdf
But we used the grape panels. We chose the Blue Sky Solar Boost 3024i controller with the meter. Northern Arizona sells that and the combiner and the big baby box and all the circuit breakers and wire (it's expensive but be sure to install the GFCI- shown in the schematic as GFP, AS WELL AS the Midnite Solar Surge Protector). The GFCI, Surge protector and the STAR (toothed) washers that peeps fail to install can make your system and possibly your house hurt you or go up in flames.
RE: Solar Electric Question - MarkP - 09-15-2012
The GFCI disconnect is actually very controversial. It disconnects the ground as well as all the power conductors. Some people think this is crazy, yet it is somehow in the code as a requirement when the panels are on your roof. It is not required when the panels are mounted on the ground. I guess that the concern is that you can't shut off the panels at the point of entry like you can for a feed from the grid. If there is a short somewhere the rational is that you have to disconnect all possible paths for electricity including backflow through the ground. Statistically though, the times when power flowing through the ground will be what starts your house on fire, while not impossible, are vanishingly small. In return for eliminating this remote possibility you have accepted that at the first sign of electricity going somewhere its not supposed to, you will un-ground the system. Frankly, that IS crazy and probably an example of the tail wagging the dog. Many people ignore this requirement if they feel they can get away with it bureaucratically and they do so with a clear conscience. I am strongly considering building a little power shed to house batteries, generator, and solar panels on the roof. It won't be part of the house so no code requirement. That may in fact be the safest solution all round.
When I first saw the code requirement for GFCI it took me a while to understand that they were breaking the ground, which on the face of it seems stupid without a very good reason, and I still am unclear about what that good reason is in the minds of those who wrote the code. I admit that there may be a special risk posed by solar panels in that you can't just shut them off and they are out of sight, out of mind up there on the roof. I guess firefighters are uptight about things that cause fires up in your attic. Perhaps I shouldn't be so judgmental but I am not the only one. There are serious doubts about the wisdom of this GFCI business as it is called out in the code. Then again solar PV, while not new, is expanding rapidly and does have its own unique challenges and risks. Perhaps there are some "whodathunkit" risks covered by this code. As a kind of way out there analogy, certain gliders that have no fuel or power on board have caught fire and been destroyed because when parked in certain positions relative to the sun, their canopies act as magnifying glasses and set fire to the upholstery. Whodathunkit?
RE: Solar Electric Question - dayna - 09-15-2012
I just got our most recent electric bill yesterday. It was $152 for 33 days and that was WITH mostly using the dryer (hung up the drying line towards the end of that bill) a fridge and part of the month with the hot water heater.
The next bill will show what we saved with using line drying (mostly, I like to fluff it), tap cold water, solar hot water, and a propane oven. We purchased a grill and propane oven since using the stove and oven makes the house so hot!
We also have mostly LED lights (and we've had them for years). Probably the biggest cost to us is the fridge and the TV.
Unlike a lot of people though, I'm at home all day so I use electric during the day while most folks are at work.
Dayna
www.E-Z-Caps.com
RE: Solar Electric Question - GuitarDude - 09-18-2012
Hey all. Just checked back on this post..Nice. lots of replies & good info. Thanks everyone.
RE: Solar Electric Question - rainshadow - 09-18-2012
It was recommended to me to have three of the midnite solar lightning arresters installed. I'm not exactly clear on the specific locations of those, however. Can anybody help clarify that for me?
Also, where can I buy them here in east Hawai'i (besides online)?
Thanks!
-- rainshadow
RE: Solar Electric Question - solarrayes - 09-18-2012
We sell both AC and DC Lightning Arrestors. Raye usually brings them to Maku'u Market on Sunday...we set up with the row of vendors that bring their own tents and we're in the closest row to Hwy 130. Otherwise you can call us at 968-1484.
http://www.solarrayes.com
RE: Solar Electric Question - mailes - 09-18-2012
Rain...why would you want to buy them locally? Unless of course you enjoy paying 2, 3 4, or 5 times the price? Whew.
Forego Delta arrestors! Install 1 in any box that has circuit breakers.
I.E., If you have a pv panel combiner box, 1 goes there
If you have a circuit breaker box for controller to battery connection, 1 goes there.
If you have a circuit breaker box for your 12v wiring, 1 goes there
If you have a circuit breaker box for your 120v wiring (maybe that is the 120v power coming from the inverter) 1 goes there
If you have a circuit breaker box for your 120v wiring coming from the grid, 1 goes there.