Need help on Solar

System

I have been researching different stuff on solar and understand that "Thin Film" panels will be cheapest. I am not sure how to figure out just what I need. I know I should start with a system that I can expand. I guess I would have to choose the item (light, computer, tv, etc.) that I want to power and then build a system that could do it. Correct? Not sure of all the components I need. Any good suggestions on a list of them and how to configure them? I am thinking I need a solar panel, power inverter and battery? What else? How big of a battery? Can you connect the batteries together as you need more power output or for a longer period? Like a daisy chain? Any help would be appreciated! :roll:

Thanks,
Outyounder

icarus

Re: Need help on Solar

Don't reinvent the wheel, spend a bunch of time reading on this forum and go from there. Many of your questions are bound to be answered here. Use the search function above,

Good luck,

Tony

12vman

Re: Need help on Solar

Outyounder..

What I would suggest is to pick the items that you would like to operate with solar and study the loads of each carefully. Don't forget the length of time that you'll be using each item because this is an important factor when using solar power. With this information and a few other factors, (location, shading issues, ect.) you'll be able to build a system to cover your needs. Battery sizing, how many watts of panel, ect. will be derived from this info..

I agree with icarus. There's a mountain of great information around here but it's hard sometimes for the everyday Joe to understand..

I'm very happy to see that this forum finally provides a place for the folks that want to learn and to understand how this stuff works. I just wish the senior members were a little more subtle and try to understand that the folks asking questions here are pretty much clueless to the facts. Compassion comes to mind..
Don

BB.

Re: Need help on Solar

Are you planning on doing this yourself, or are you looking for a "turnkey" system (somebody else gets the parts and puts it together at your home)?

In general, Thin Film panels are not always the best solution... Many are not made very well and quickly fail. Also, they are less efficient, so require more panels/larger area to collect the same amount of power. You then need more space and more racks to mount everything (increased costs).

In any case, thinking about panels first is placing the cart before the horse.

First, you need to know how much power you require... Reading labels on appliances is generally not very accurate... Most of the time, the labels list maximum power required rather than average power over time (for example, a refrigerator may use 100 watts, but only 10 hours per day). One accurate method is to measure with a $30 or so Kill-A-Watt type meter (use for several days or weeks). Another is to read your utility bill and see how many kWatt*hours per month you use...

You will need some basic electrical equations such as:

P=V*I (power = voltage * current)
P=V^2 / R = I^2 * R (voltage squared divided by resistance, etc.)
V=I*R

V is in Volts, I is in amp (or Amperes), and P is in Watts (or kiloWatts where 1,000 watts = 1kW)

The energy you use is known as Watt*Hours -- So a 100 watt light used for 10 hours = 100W * 10 Hours = 1,000 Watt*Hours (WHrs or WH) = 1 kWhr

Next, you will need to decide what it is you are trying to accomplish... Save energy, save money, prevent global warming, prepare for a natural disaster (3 days - 3 weeks without power) or whatever...

And, you will need to look at your home/solar site and see how much sun you will get... Solar only works in full sun, if you have shade (trees, buildings), marine layer (fog/clouds/etc.) will make solar virtually unusable for your location--you pretty much need full sun from around 9am to 3pm, summer and winter. There are times when the numbers can be bent--but you have to watch what you are doing to still make economic sense.

Since, you seem to be concerned about price ("cheapest" solar panels)--a few hints...

1. Conservation; insulation, double pane windows, energy star appliances, weather stripping, turning things off, change lifestyle, etc. are all the first place you should be investing your money and time... It is almost always cheaper to cut power requirements rather than generate the needed power with solar.
2. See #1 again.
3. Solar Thermal; generally, solar hot water and solar space heating is the best bang for your buck... Especially if you have electric hot water. Systems are relatively inexpensive--but do require quite a bit of maintenance to keep running (pumps, water leaks, air locking, etc.).
4. Solar Grid Tied Power; can be competitive with electric power in high cost states (like California), especially with rebates. If you have a good site for solar, your utility supports "1 year net metering" (basically, utility acts like a giant AC Battery over a 1 year period) will work well. Also, no maintenance required (wash off panels once every month or three--if you like).
5. Solar Off-Grid and/or emergency backup power; Can be a good solution for homes that are not near power lines. Also, can be useful where electric power is unreliable or you have long storm/natural disaster outages (hurricane, ice storms, etc.)... However, power is expensive and batteries require maintenance and replacement every 5-10+ years. For an urban home with reliable utility power, many times better to just get a backup generator (small like Honda eu2000i or larger permanently installed if you have a big home).
99. Wind Turbine; for a very few people that live in windy areas, wind turbines may make some sense. Wind Turbines look cheap--but installation costs can be high, turbines can be noisy, and there are few mechanically reliable home scale turbines out there--having to hire a crane every year or so to work/replace a wind turbine (plus the other costs of parts/replacements) have made most of us here pretty much recommend avoiding them.

In your case, it appears that Hillsboro Oregon may not be a very good place for solar power (using Portland, OR)... You get roughly 1/2 the sun of San Francisco Ca. (near where I live). So, that makes any solar installation virtually twice as costly ($$$/kWhr) as down here.

So, for example, I have 3.5 kW of solar panels on a Grid Tie inverter. My system (my panels don't face south, but at 155 degrees, so change default, ~$29,000 installed (retail price installed, includes engineering and permits), before $8k in rebates and tax breaks, assuming 25 year life and no interest charges):

$29,000 / (4,875 kWhrs per year * 25 years) = $0.24 per kWhr

Your system (defaults) would generate about 3,562 kWhrs per year (assuming everything else matches the defaults):

$29,000 / (3,562 kWhrs per year * 25 years) = $0.33 per kWhr (no rebates)

If you are looking for a battery backed system, running all of the numbers, you would end up paying $1.00 per kWhr, or more (a hybrid Grid Tied / Off grid system would probably cost you between $0.50 and $1.00 per kWhr).

If you compare that with the cost of power in your area... An battery backed system is going to increase the cost of your power by 5-10x...

And, if you are off-grid and/or want emergency backup power--you will probably need a generator backup anyway--so you still have those additional costs and fuel storage/supply issues.

I tend to recommend a small generator (like a Honda eu2000i) as they are reliable, quiet, and very fuel efficient. You only need a few gallons per day of gasoline for backup power (at full power 1,600 watts for 1.1 gallons; at 1/4 power, 400 watts for 15 hours on 1.1 gallons of fuel).

The larger home emergency generators can easily use 1-2 GPH, or more... May be worth it--but for long outages, fuel costs (and storage requirements if not Natural Gas) can be a big issue.

-Bill

System2

Re: Need help on Solar

Wow that gave something to work on! I really appreciate it. I will probably start with supplementing my energy by just choosing a few things to run. I can get a meter to see how things are drawing on power and go from there. I may start with running lights at first. I will keep you posted! I am sure I will have more questions as I get started.

Outyounder8)

BB.

Re: Need help on Solar

Generally, it is not real easy to start small and enlarge a solar PV system... If you get a large charge controller and a small number of panels, the charge controller will waste power.

If you start a small system with just a few batteries--it is generally not recommended to add to an existing battery bank. The new batteries will tend to take over more of the load (because they are better) and will sort of age until they are as "old" as the original batteries--then all fail about the same time.

Also, small off-grid type systems will tend to be a 12 volt battery bank (typically 1kWatt or less). A medium size around 24 volts (2-3kWatt). And a large system would be 48 volt (3kW and larger)--so you end up having to replace inverters as well too as you scale up the systems.

What you might do is size your "emergency" load--like running your refrigerator (a newer Energy Star kind--of course), a few lights, and a radio or small TV... Once you get some experience with the system--you can then decide to go larger to power more of your loads--and move the small system to a cabin--or just keep it for emergency power and build out a large Grid Tie system (assuming your AC power is reliable and your utility supports Grid Tied Solar with Net Metering).

-Bill

12vman

Re: Need help on Solar

Thank you, Bill. You're a great asset to this wonderful site!

It may seem like your "Chewing your Cud", Per Se, over and over again but IMO it means so much to the newbie to get that personal touch! All of the reading in the world will never compare to direct, personal interaction. I was one. I remember. And still learning..

Kudos to you and to everyone here freely providing information on alternative energy and the products available. Your efforts will not go unnoticed..

BTW.. I have a line on (20)-Hawker Power Safe 3VB11's that aren't very old if you know someone that could use them. They can be shipped..
-Don