Anybody here into Solar Power?

By TimGary (****)

Date 01-22-2012 20:17

Sounds smart John. Please keep us updated on how it holds up.
Blog?

By RioCampo (***)

Date 01-22-2012 23:13

If you add much power, take a look at the wind turbines. 300-600 watt ones can be had for good prices. Some will even have the charge controller built in.
Big solar power gets expensive real quick.

By jwright650 (*****)

Date 01-23-2012 12:49

Rob, I agree about the big solar stuff being expensive...man I cringe when I browse through the sites looking at the upper end solar panels, controllers, battery banks...ect.

Hopefully one day someone will hit on a formula for a cheap inexpensive way to get lots of energy from the sun.
I see that someone on Youtube uses mirrors to double the amount of energy from their solar panels. I have to wonder though if they will over heat them and kill the panels prematurely.

By hillbilly delux (***)

Date 02-01-2012 21:18

you can buy the panels on ebay for about a dollar a piece and tab them your self which is what I did. Panels can take a pretty good amount of heat. Give me a day and I will give you a post on how to build your own solar panels. Also if your interested in building your own wind generator. Again take a look at ebay and do a search. Theres a guy who lives in Derby Kansas that explains in his book how to build your own wind turbine for around 3k using off the shelf parts. Cost of book about 20 bucks. Found it on ebay but thats been years ago.

By jwright650 (*****)

Date 01-23-2012 12:50

Tim, I'm not sure about blogging...LOL...I'll just try to keep this thread up for now.

By DaveBoyer (*****)

Date 01-23-2012 03:05

You might consider using LED backup lights for lighting. Some of My sailboat friends have gone that rout. I would not use the incandescent lighting given the available choices today. A 100 watt 120V load will pull 10 amps on the 12V side.

Some solar pannels are "shadow tolerant" and others loose ALL output if a shadow crosses a portion of the panel. This shouldn't be a great problem on a fixed location system, but it was an issue on boats.

I used golf cart batteries, 6 of them for a 645 amp hour 12V system. I got "seconds" from East Penn Manufacturing "Deka" brand at the factory, these were the most bang for the buck. This system would power the 1800 watt inverter at full load [180amps @ 12 volts] for a good while before output voltage dropped.

I didn't use solar, and made minimal use of a wind generator, recharging was from a 190/165 amp alternator and a multi step voltage regulator driven by the engine. I lived off grid this way on a boat a good portion of '91-'03.

If You let that small refrigerator run full time, I don't think You will have enough power from the solar pannels You have to keep up.

What is the standby draw of Your inverter, or do You only power it when You need it? Many don't have a low draw standby circuit. If I remember right My Heart EMS1800 draws .03 amp at standby. I have a different brand I was going to install in My truck that draws a whole lot more, and must be unhooked when not in use.

By jwright650 (*****)

Date 01-23-2012 11:58

Dave sounds like you and some others have some experience with this stuff. That is great...I may need to pluck your brains if I have any trouble figuring this stuff out.
My inverter is a cheap one so I turn it off when not in use...it has cooling fans that run continuous, so the draw at standby is probably pretty significant. I agree about the incandescents, but it was all that I had on hand when I was doing the wiring.

Yesterday was the first day where I played with it any to see what the solar panels were producing. It was pouring down rain all day and I unhooked the battery to check the voltage straight from the panels and it was hovering between 16.7 and 17.1v without any sun. It was enough current to run one of the 2 12v 5w CFLs(no battery, just solar panels).

The HF 45w kit has what I thought was a charge controller in it, but I'm not 100% sure...how do I tell so that I don't cook my battery with 24-25v on a sunny day? I have a separate charge controller but didn't use it...yet. The instructions in the HF kit never mentioned adding one, it only stated that the battery and inverter were not included.

I need to purchase some dedicated amp/volt/watt meters and wire them in so I can keep an eye on things.

By Superflux (****)

Date 01-23-2012 21:40

Great topic,
and perfect timing. I am just starting to do research into an off the grid subterranean home. There isn't/wont be a power pole with in a 1/2 mile of my property. LEDs are first on the list.
Are all solar panels created equal? Is there a benefit to spending xtra $$$?
Energy storage seems to be the BIG issue. Are Forklift batteries a better bang for the buck than Deep cycle marine?

By RioCampo (***)

Date 01-24-2012 00:32

All solar panels are not created equal. There are differences in efficiency rates as well as voltages ie. 12, 24, 36, and etc. Generally, the higher voltage is better efficiency.
The are essentially two kinds of solar panels on the market today. One is mono crystalline, these are used on homes and commercially with rigid frames. The other is relatively new, called thin film solar. It looks promising as the efficiency rates are around 15%. It is not in a rigid frame as the other type is. This should lend itself to many more applications than mono crystalline type panels.
Another thing that would be nice over the long term is nickel iron battery cost. Currently, you would need to rob a bank to afford a set. Most people go with standard lead acid style batteries. Surrette makes very good ones (think submarine batteries).
You can also extend lead acid battery life with what is called a desulfator. It sends a small opposite charge through the batteries to remove the charge buildup from the lead plates. This technology has been used in government installations since the 50's that I know of.

By DaveBoyer (*****)

Date 01-24-2012 03:12

There are actually 3 typs of panels, single cristal, pollycristilin and amorphus thin film. The efficiency and life span on single cristal and polly cristilin is close to the same, the thin film requires 2x the surface area and will deteriate over time. Cost per watt was about the same when I last checked, but that was near 10 years ago.

Surett does make really good batteries, but they cost a fortune.

Forklift batteries are great for a large system.

Be careful of what You are buying in "marine" batteries. Many are combination starting/deep cycle batteries, not really deep cycle batteries.
The difference is plate thickness, true deep cycle batteries have thicker plates, but fewer of them.

The charge used for de-sulfating is the same polarity as charging, but at about 15-16 volts with limited amperage and duration.
Chemical additions keep the lead sulphate from cristalising in a gell battery, and higher voltages than 13.8 WILL damage them.

Hydrocaps can be used to re-combine the hydrogen and oxygen given off while charging and greatly reduce water loss [battery maintainance].

Wet nickel cadnium batteries have extremely long life with proper maintainance, but are expensive and have a greater difference in charging voltage and output voltage that creates issues in a system.

Charge controllers are a good idea on systems that are not being used & monitered all the time. Some [smaller] panels have low enough output voltage that regulation is not needed, but any system that has enough panel output that it doesn't continually operate at a deficit will at some point need regulation.

The best book I ever saw covering this topic, but geared towards boats [now fairly old] is "Living on 12 volts with ample power" By Dave Smead & His wife Ruth.

**** GRID TIED SOLAR SYSTEMS***

These are a whole different ball of wax.

Grid tied systems operate at line voltage, and the inverters match line frequency. No voltage regulation is required, as the system is not large enough to affect grid voltage. There is no storage capability, You use grid power when You need it, and the system puts power back on the grid when the system output exceded Your use. The rate the power company pays You for what You generate depends on Your home state's laws.

One of My friends has a 9 KW system in Tracy California. It is mounted independantly from the house. It cost about 40K out of pocket after all the rebates & tax credits. It looks like it will pay off in about 7 years. California laws favor solar systems much more than Pa. where I live, and the sun shines a much greater portion of the time.

*** Solar domestic water heating***

We installed a Heliotherm brand system about 1980. This system uses (2) 3'x8' pannels and a 75 gallon heat exchanger storage tank. A few hours of direct sunlight around mid day gives water too hot to shower with. We get such weather about 1/2 of the days of the year. another 1/4 of the time it doesn't help at all, the remainder somewhere in between. This is an antifreze filled system.

The solar heated water is plumbed to deticated selector valve at the tub/shower, sink in the shop and as the feed water to Our oil fired sidearm boiler.

I did replace the tank/heat exchanger about 5 years ago, other than that the system has required no maintanance.

An alternative to an antifreze/ heat exchanger system in cold climates is a freshwater drainback system. These only put water in the pannel & exposed piping when the sun shines, and drain back when it doesn't.

Seasonal freshwater systems are simple to build, We built one before We installed the present one, but there was nothing to be gained from using both.

By Superflux (****)

Date 01-24-2012 05:12

XLNT info.
I have barely scratched the surface on this. Thanks

Efficiency is the issue, with no external (off the grid) back-up available.
DC cannot be jacked up or down like AC, right? Here in lies one of the great dilemmas facing us DIY'fers.
I can create a more efficient voltage, but it will cost a fortune to get the available "appliances" for the end use.
transmission loss is not the issue, just an economic storage system.
I've even considered a large volume concrete storage tank of compressed air to drive a wind turbine as a back-up system.... got to explore all avenues.

By Superflux (****)

Date 01-24-2012 05:17

So,
If I have equal abundance of wind and solar available...
Which is the more cost effective for initial investment?

By DaveBoyer (*****)

Date 01-24-2012 08:05

If You are only a half mile from a pole, it is probably cheaper to run the wire if You expect to spend much time there.

You need to decide on how large a system You need [how little electricity are You willing to live with] This dictates what equipment You will use.

Consider using propane for coking and refrigeration and using a generator when You need huge ammounts of power for a limited time.

Wind generators do damn little at wind speeds below 12 kts, and many don't give rated output at less than 18-20 kts. But they do work on windy nights, and solar NEVER works at night.

Generally, a site should have wind measured over time to see just how mush wind power is available. You can probably find a map someplace that will give You a rough estimate.

My experience is with 12 VDC to 120 VAC inverters. For larger systems [over 2KW], it makes sense to use a higher DC system voltage, and the apprpriate inverter.

I have a transformer type inverter on My boat. These are heavy and expensive, but give 3:1 surge capacity rather than 2:1, and can be configured to operate as a high capacity battery charger when 120 VAC is available. Mine does not charge well from a small generator, however. I cant comment on newer ones, Mine was built in 1989.

Compressed air for energy storage will loose EVERY TIME.

You need to give more information on how You want to live there, and how much of the time.

By jwright650 (*****)

Date 01-24-2012 12:01

Golf cart batterirs seem to be the bees knees for these residential systems(at least the ones on YouTube). They come in 6v with 250Ah or more(4 or 5 times as much reserve as a regular deep cycle battery) and you can wire them in series for whatever voltage system you want to run.
http://www.trojanbattery.com/Products/T-1456V.aspx
12v is easier math and there are lots of 12v appliances already out there, however if the panels are going to be any distance from the system, you can wire then in series to add up the voltage so that you can get away with smaller wire to travel the distance without a voltage drop, then step it back down at the charge controller. ie. 12v panels wired in series can add up in increments of 12...so for a 24v system every two panels are wired together in series or for a 48v system every four panels are wired together in series and then combined in a junction box and fed to the system. The Ah (amp hours) add up, so the more batteries you add the longer the reserve capacity.

Reserve capacity = usable minutes at 80 degrees F @ 25 amp draw to 10.5V

Amp-hour capacity = Available amp-hours, at a fixed rate, over a given period of time (e.g. 20 hr rate, 5 hr rate., etc).

The WindMax is a good turbine comes in several ratings and can put out more voltage with less wind than some of the other turbines. Some of the other are better producers at high winds, but this one does well at low wind speeds.
http://www.youtube.com/watch?v=9tzaK38fOqc&feature=related

By DaveBoyer (*****)

Date 01-25-2012 02:23 Edited 01-25-2012 03:45

"you can wire then in series to add up the voltage so that you can get away with smaller wire to travel the distance without a voltage drop, then step it back down at the charge controller"

How do You plan to step it back down at the controller? Once You have done the series connections, You are stuck with the voltage You have.

I used a "Windbugger" wind generator. This has low end performance about what the guy shows in the video, makes 20 amps at 20 KTS, but at higher wind speeds, a centrifical brake activates to prevent overspeed. This unit was nearly silent in operation when everything was in good shape. This is a wound generator, as is the "Four Winds" brand. These units do require more maintanance than alternators like the one in the video or the Air Marine 400.

The units I mentioned are similar in output. For what it is worth, a friend uses (2) Air Marine 400 units to provide power on His sailboat, along with a solar panel that I doubt contributes much due to it's location. I can't say what a new Air Marine is like, but the older ones made a fair ammount of noise.

The 645 amp hours I mentioned from the (6) golf cart batteries was at the BCI 20 hour rate. This was fine on a 43' sailboat living the cruising lifestyle, but that is a low energy use lifesyle that many don't want in a house.

If You are attempting to run a house size system You would be better with the fork lift batteries as oposed to a great number of golf cart batteries. Space requirements on a boat dictate that You use what You can fit in the space You have, not an issue in a house.

EDIT:
An important point that I should have included somewhwere on this thread is that a lead/acid batteries in good condition require 120% of the amp hours discharged to be put back in to get to the same level of charge that was started with. This is the recharge rate that the BCI [Battery Counsel International] uses to determine amp hour rate of a battery, over (5) discharge/recharge cycles. As batteries deteriate, capacity will be lost.

Anyhow, use the 120% figure when calculating charging acpacity Vs. use.

By RioCampo (***)

Date 01-24-2012 22:42

Wind is a little cheaper for the turbine depending on system size. But and this is a big but, you have to have a pretty high sustained wind to turn a wind turbine, a 5 mph wind won't cut it. Most turbines I have seen need at least 12 mph to generate electricity.

If you are looking for something to run the entire house with appliances and a/c, and etc. you are looking at a lot of wattage. 10k watts plus pretty easy. That is some serious cash. You will also need a standby generator to supplement times when you have no wind or sunshine. I'm assuming you have a welder with a generator on it, but are you the only one who will be there when it is needed?

Have you looked at the cost of dc or propane refrigerators? They are dangled expensive, although you get much more efficient energy use from them. Decent sized dc freezers are outrageous.

There are several options for batteries as discussed already. You need to know that most systems are not designed to go below 80% capacity. Even though a battery says it has say 450 amp hours, you are not going to by able to use them without significantly reducing the useful life of the battery.

The first thing you probably should do is determine what appliances and accessories you will be powering daily. There are lots of online calculators out there. This one has several options: http://www.freesunpower.com/system_sizing.php
It will start you down the road to determining the requirements needed.

It would most likely be unrealistic to expect to put a system together for under $20,000 that would meet the needs of a standard sized house. You would need to calculate the number of years you expect to use the system vs. the amount of electricity you would use during this time. Don't forget to account for the increase in the cost of electricity. I have a feeling the new EPA regs are going to hurt.

By DaveBoyer (*****)

Date 01-25-2012 02:35

The guidlines I am familliar with suggest only discharging to 50% of the 20 hour rate amp hours.

There is a formula, "Pukerts equasion" that attempts to give a more accurate measure of discharge, as 3 amps for 100 hours drains a battery a whole lot less than 100 amps for 3 hours, but both are 300 amp hours.

I used an amp hour meeter from Cruising Equipment Company that just measured amp hours, Pukerts be damned. Later meeters used Pukerts to try to predict power remaining to a more accurate level.

No didrespect to Pukert, whoever He was, but I am probably spelling the name wrong.

There are apartment size propane refrigerators that are not as expensive as the super insulated ones, but I have no idea where to source one locally.

I used a mechanically driven refrigerator/freezer system on My boat, at the time it was the best way to go on a really large system, that did not have generator power. The compressor is an auto AC compressor, about 1 ton capacity. There are holdover plates in the fridge & freezer, much like an ice cream truck.

By RioCampo (***)

Date 01-25-2012 02:51

Typo on my part there Dave. Yes 50% is the standard for most systems.

By Cumminsguy71 (*****)

Date 01-24-2012 01:14

I look forward to seeing how those harbor freight ones hold up. I've been wanting to do solar on our house because we face due west on the side of a ridge so sun is always available. I had a friend back in high school(20 years ago) who's parents had solar panels and plumbing under it for hot water in the summer. In the winter they had a wood burning stove with a coil behind it so they could have hot water in the winter.

By 99205

Date 01-24-2012 06:28

Harbor Freight = Dollars directly to China's military. Screw that junk.

By Cumminsguy71 (*****)

Date 01-24-2012 17:25

Very true.

By jwright650 (*****)

Date 01-31-2012 20:15

Well the system is keeping the battery topped off. I have been running the lights at night for several hours while I'm out there and never saw the voltage drop more than 1-2 tenths of a volt. I'm looking at building some LED lights just to try it....I was thinking about using a plastic 4" ceiling fixture box w/ flat cover and drilling the cover to mount the LEDs in. I was planning on 2~18 LED arrays(3 in series x 6 parallel x 2) Got the idea from someone on Youtube.

also found a LED parallel/series resistor calculator that works pretty well.
http://led.linear1.org/led.wiz

12.7v battery voltage
3.2v forward voltage
20mA forward current
18 LED array(times two to get 36)

Wizard says that I need a 180ohm~1/4watt resistor in each series string. (3LEDs in series with the resistor)

By DaveBoyer (*****)

Date 02-01-2012 03:57

When the white LEDs came out I knew someone building ancor lights for boats. He used a pulsed power source, claimed it gave more light output without shortening the lifespan of the LED, which are aparently not tolerant of continuous over voltage.

By jwright650 (*****)

Date 02-01-2012 13:20

From what i've been reading, if you run them too hard with too much voltage for too long they will burn out. But like you stated, if they are rated at 3.2v continuous and 3.7v peak, you can pulse them at 3.7v for short periods(milliseconds) and your eye will never notice, (like the flash rate on a computer monitor), and they will last just fine.

By Sourdough (****)

Date 02-05-2012 05:35

John, I've read some about wind power and windmills. I have been dreaming of being completely off-grid for years.

By DaveBoyer (*****)

Date 02-05-2012 06:46

The reality is not as good as the dream. If You can run a cable to grid power rather than having storage capacity, You are way ahead of the game.

Your state laws have a great impact on the payback period of a grid tied system, however. My friends system in California just runs the meeter backwards when it overproduces, but here in Pennsylvania You sell power back at bulk rate [much lower than You buy it for].