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This is just an example, no endorsement or plan to get it. It represents my near term need, not to get off the grid or even sell excess to HELCO, but as a back up if/when there are power outages, possible switching to it as the main during low load times, just opening the breaker. 1KW seems like enough for now, mostly pulling current from the batteries.
http://www.amazon.com/1KW-VISE-COMPLETE-SOLAR-SYSTEM/dp/B004XEJWM6/ref=sr_1_12?s=lawn-garden&ie=UTF8&qid=1350668706&sr=1-12&keywords=1kw+solar+system
1KW VISE COMPLETE SOLAR SYSTEM
6 panels
$3,472
This price doesn't include installation or the batteries. Is there any experience out there with the price range here for an equivalent system with installation and without the batteries, preferably HIT panels?
This is an easy and interesting reference for the number of batteries. My current usage is 7KWh/day, planning to halve that soon, so with this guide, it looks like 10 250AH batteries could last for 5 days.
quote:
As a rough rule of thumb for home solar systems, the total battery capacity (in amp-hours) should be five times your daily usage. 5 days of storage or backup is commonly used. To work out what storage you require, just take your average daily usage in watts and divide by the battery voltage. For example, if you use 3 KWh (Kilowatt-hours) or 3000 Watts of electricity per day and your solar electricity system operates at 12 volts, then dividing 3000W by 12V gives you 250 AH. It’s important that the battery is not discharged completely and we suggest discharge should not be more than 50%. At 50% discharge you will need 500AH of battery storage."
*Japanese tourist on bus through Pahoa, "Is this still America?*
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You are looking at a grid tied solar system.
In other words it will not work for battery storage.
The main thing that you want to do with any battery system is not only size the bank for the loads after dark and cloudy weather, but also to set up a single series connection for battery arrangement. Any parallel connections on batteries will shorten battery life. Read FEB/March 2012 Solar Pro. I keep a copy with me at Maku'u market on Sundays. Voltage for inverters and batteries becomes the formula that you need to work on the most before buying any system components. Yes there are lots of parallel banks out there but this is not what you want for long battery life. We all know what the biggest complaint for off grid systems tends to be. Battery life.
Raye
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1. Chinese solar panels are available for $1/W locally (Hilo). I find it hard to believe that the inverters/mounting hardware really add $2.5/W.
2. Specs from Rolls say you should avoid more than 3 parallel sets in your battery bank. "No parallel connections" makes sense from an engineering perspective, but as with everything it's really a price/performance tradeoff -- eliminating all parallel connections means bigger/more expensive batteries are necessary to achieve any real capacity.
My opinion: grid-tie is a scam since you're still beholden to HELCO. Replacing batteries every few years is still cheaper than the minimum HELCO fees. For that matter, grid power here is so expensive that gas generators are cost-competitive....
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I bought 720 watts of panels for about $1,000 (good deal, that), eight 6-volt costco golf cart batteries for $875, an mppt charge controller for $450, and I got a 48 volt to 120 volt 2,700 watt inverter free. I'm not done yet as I have to mount the panels still and it is surprising how much electrical wire and fittings costs. I must have spent $2,500 so far but I have bought most of what I need. The rest will be labor.
Using the mppt charge controller I can put the panels in series so they will always put out something to charge the batteries even on somewhat cloudy days. I think that this is important in an environment like Puna where sun intensity varies so much compared to places like the desert southwest. The batteries will be put in series (48 volts) since that is what the inverter requires. Whether in parallel or series, the batteries will store the same energy. The advantage of higher voltage is that you can use smaller gauge wire as well as less risk of uneven battery discharge and the consequent shortening of battery life that causes.
I didn't do any elaborate calculation of how much battery capacity to install. I had an inverter that required 48 volts. If I need more battery capacity in the future I think I will buy eight larger batteries rather than 16 golf cart batteries. One question I have is whether I got enough pv capacity. I will adapt my usage to pv capacity. It is a good exercise to mentally slap yourself whenever you say "I use x kwh per day now". Unless you are made of money, what you use now while hooked up to the grid is literally not relevant. You won't be heating water with electricity off grid, or if you do, you're officially crazy and you should just burn $20 bills for heat. It is what you can stand to live with or without off grid that is relevant.
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quote:
Originally posted by solarrayes
You are looking at a grid tied solar system.
Actually, no. Grid-tied Solar Electric Systems generate electricity for your home and route the excess power into the electric utility grid. I don't intend to do that. My main power will be from the grid, and the solar is supplemental and a backup. When I am operating solar, I will open the breaker to HELCO so I am not connected to the grid. I think this will help the permitting since it's the loading study that costs so much and takes so much time. My payback will come from not using HELCO power at different times, and continuing to have power if there is a HELCO power outage. It might be difficult to understand if the view is everything or nothing. My application is in-between, have no desire to be totally off grid power but would like solar to be there, especially when I am on vacation and keeping my security systems powered up.
Those high capacity battery packs could be better than series-parallel battery banks but don't know anything about the cost. Will look into those.
That system was just an example and it definitely uses Chinese cells. Here is another one, similar, 1KW, 4 panels, Chinese cells:
http://www.wholesalesolar.com/system/auo...e-kit.html
My question was if anybody had any reference cost with a 1KW installation with HIT panels. Chinese panels might not be a bargain for much longer, there is a 30% tariff being applied to them soon.
*Japanese tourist on bus through Pahoa, "Is this still America?*
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The systems you linked to are grid tied systems--Enphase micro inverters are only for grid tied.
There are a lot of considerations in doing any solar system. For example, how many batteries do you need? Well, how long do you want to go before you start the generator? What is your load? Then you know how many amp hours of battery you need. 500 amp hour batteries in series do not increase the amp hours available. To get more amp hours you need different batteries or a parallel bank.
What are the various voltages of the panels? I just put four panels in series onto my shed. The open circuit voltage is 33 volts. In series I get 132 volts. My inverter can handle 140 volts, so no problem. Put on a fifth panel...oops.
My grid tied systems has 12 panels in series. Big voltage--do not touch.
And, as was mentioned above all the other electrical parts can add up fast. In one sense solar is easy, but as they say the devil is in the details.
Jerry
Art and Orchids B&B
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Well, again, those were just examples for comparitive pricepoints and the difference in grid tie is the inverter. There is grid tie, off grid and on grid. I am referring to an on grid system. This site has the comparisons, although they don't seem to use Sanyo HIT panels:
http://www.civicsolar.com
Similar project:
http://www.civicsolar.com/solutions/on-grid
1.5 kW Central IL Residential Solar Installation
Similar to my plan, except smaller scale as lanai roof:
http://www.civicsolar.com/installation/s...ect-canopy
Santa Ana 2.7kW Bifacial Sanyo Project on Canopy
There was a guy in Hilo using Sanyo HIT panels but he switched to Chinese. He is making news, because he bought over 300 Chinese panels several months ago for about $55K and now found out the tariff is retroactive plus ranges from 30% to 256%. He has now been ordered to pay a tariff of $140K. I believe they are using Kyocera panels so I will just call and get a rough estimate.
http://www.eenews.net/public/Greenwire/2012/07/25/1
'Shocked and puzzled' businessman gets caught in crossfire of trade battle
*Japanese tourist on bus through Pahoa, "Is this still America?*
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If you want to see the Sanyo/Panasonic double HIT bifacial panels in action (though not truly the BEST install for the bifacial HIT's , UH-Hilo has a Florian rack mount system in the see through upper roof of the Kipuka lanai. Photo link:
http://floriansolarproducts.com/new%20Ca...lo%203.jpg
I personally WANT the Florian all aluminum patio cover system, Link:
http://floriansolarproducts.com/new%20Ca...nt%208.jpg
(best part is that is a fully engineered racking/cover system & the whole cover is a part of the solar system & is covered by the tax exemptions}... only problem? getting it here.... the UH-Hilo installers are not he ones that Florian references, and the Florian references on based in Oahu, have only done the Florian install in Oahu & their on-island company reps are too busy with commercial installs...We have already had such problems (almost a full year of playing wait & wait & wait with electrical upgrade instal here, that it seems that to go with this company (who already acknowledge they are too busy with commercial installs) would be a nightmare in the making.
Oh, while researching all of this we did find that the China HITs are using the rating differently than the Sanyo/Panasonic HITs, they are rating on the bifacial max potential, rather than the single side max.... so you need to compare them with that in mind...
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"it looks like 10 250AH batteries could last for 5 days."
Try to get that guaranteed in writing.
I'd have to say that just about all the people I know off grid just hope to make it thru the night and then evaluate how to make it to the next morning - is my system charged enough?, will the sun give me enough charge today? Should I run the generator? Nobody thinks 5 days, can't really think of any friends that even think 2 days. Not every sun day is equal , some days my system may produce more than 4-5kw per kw of PV, but I've also had days of less than .5. Any other common lessons to pass on, hmmmmm, most decide their initial system was too small (usually based on size their installer sold them), usually wanting more panels, some realize they didn't have enough panels for their batteries, most do better after replacing their initial battery set.
No grid tie or on grid experience, so someone with that experience might chime in. As for my off grid credentials.... Built a small learner system when we first moved here and indeed it was a learning experience. My house system was originally installed by Solarman, but with lots of discussion of choices. Initial system was 4.5kw of PV, 1350 Ah 48 volt battery bank., later added 24kw diesel generator (about 1200 hours in over 4 years). This summer I added another 1.5 kw PV. I admit, we use a lot of electricity, more than 5 years ago.
David
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That's what it's all about, talking through a topic and that becomes a learning process. What I have learned is not using the exact terminology correctly. My target system is a grid-tied battery backup system, although with no plan to sell surplus to HELCO.
quote:
GRID-TIED WITH BATTERY BACKUP
Grid-tie with battery backup systems offer the convenience of being connected to the grid with the security of having backup power during a power outage. They also allow for other power generating components to be linked into the system such as Wind, Micro Hydro turbines, or Fuel Cells. Again, these systems feed excess electricity back to the grid in the same way that a grid-tie system does, as well as providing power during power failures. You can still roll back your meter just as you would with a straight grid-tied system.
http://solarpowerplanetearth.com/images/...backup.jpg
http://www.foxfire-energy.com/pics/gtwbb.jpg
And for a more representative system with ballpark price:
quote:
http://www.wholesalesolar.com/system/mic...ackup.html
Micro Gridtie with Battery Backup Solar Power System
1,440W, up to 196.3 kWh per month, 6 Astronergy 240-watt solar panels
$5,808.00
This wiring diagram is a grid tie system which shows the main disconnect to use the system off grid, once battery backup is added:
http://solar.smps.us/gridtie-solar-wiring.jpg
*Japanese tourist on bus through Pahoa, "Is this still America?*
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