Solar power generator

[woodweasel]

Anybody have any info on solar generators? Found some on net for$2400.
Was on a website from Lee Bellinger @ Independent Living.Didnt have a lot of info, did say it had a 200 amp breaker and a smart meter?  ??? ??? :P :P ??? Daniel

[mad murdock]

My brother in law owns a company that makes them. The Goal Zero Yeti 1250 is a 1250 Watt generator that you can charge with 2 30 watt panels or charge from your wall outlet off 115v AC.

[woodweasel]

thanks m.m. I will check them out ! daniel

[clearcut]

Costco was selling a Wagan Solar Cube for about $1,300. A self contained unit that the solar panels folded out of. Folded it was about as big as a medium size rolling cooler.  If I remember correctly it had a 1500 watt inverter. It was interesting but would only run a full size refrigerator for about an hour.

[Al_Smith]

Solar via photovoltaic cells is a wonderfull idea .The drawback is the amount of surface area needed to get any kind of a usable amount of power from them .That obviously drives up the cost to a point it's not practical  .

FWIW the cost to run a fridge for a year is between 85 and 130 dollars .

[woodweasel]

ahh heck fellas what's a man supposed to do if we lose our power grid like some folks are talking about? $1300 to run a fridge for one hour? There's gotta be something out there that's a little more feasible and efficient  ??? :P

[woodweasel]

maybe I've been watching too many episodes of revolution ,I don't know ???

[Al_Smith]

Well most people including myself call that gizmo a portable gasoline powered generator .It costs about 4-5-6 times as much to produce the power but it's better than freezing your plumbing in a blizzard .

Then again I suppose you  could have an outhouse and a wash basin and do things the old fashion way .Some not including myself seem to long for that experiance .

[mad murdock]

The Yeti definitely is not a gas powered gen set, but it will provide moderate power for up to 2 days, depending on the load of course.  If you want inexpensive backup power, look for a small diesel gen set, or if you have a compact tractor, you can get a PTO gen set and run it off your diesel tractor.

[woodweasel]

I have a gasoline powered generator but that's not what I'm after! I want a solar-powered that will sustain itself for a little bit  more than 6-8 hrs of time! :

[mad murdock]

If you don't need portability and want backup that is not gas dependent, I would  put in a few solar panels into a couple marine 12v batteries and the. You will have decent power for whenever you need it as backup.

[clearcut]

Costco was selling a Wagan Solar Cube for about $1,300.

It was actually $700 for the Wagan 1500 Solar Cube. The list price is about $1,300.

Even at $700 it's a fair chunk of change for 80 watts of solar panels, a 55 amp hour battery, charge controller, and inverter.

[WoodenHead]

Solar generation equipment comes in many levels of quality and effectiveness.  If you want run a house a good system will cost.  My own off-grid system was about $60,000 eight years ago.  It was quite fancy for its time.  The batteries have a ten year warranty.  The diesel generator comes on automatically if there's not enough solar and wind generation.  But much simpler systems will do.  But it wouldn't be hard to spend $3000 and up.

[Jason_AliceMae Farms]

Woodenhead,

Would you mind sharring some details about your off-grid system?  I am interested in someday having an off-grid system if money ever allows so I am interested in some of the dirty details of your setup.

[WoodenHead]

Jason,

Here are some pictures of my off-grid system.  The system has changed quite a bit since we first built and I would sell a client different equipment today if they wanted/needed something similar (I sell this stuff).

First of all, my house:



2200 square feet (two-storey) log home with walkout basement (additional 1100 square feet).  The heating system is propane fired boiler for radiant-in floor heating (basement and main floor).  The second floor has radiators.  We designed the house from the ground up to be off-grid.

These two pictures are my 1.8kW solar array sitting to the north of my house.  We have since upsized the array to 12 x 230W panels and plan a similar sized array to be added soon to power the shop.





This is my battery bank.  If I remember correctly the batteries are about 11" wide by 16" deep by 24" high.  I have a total 12 of them.  Each are 4VDC wired in series for a total of 48VDC (my system voltage).  Each battery weighs about 220lbs.



These are my inverters.  They are Xantrex (now Schneider Electric) SW4048 inverters providing 4000W each at 120VAC and stacked together to provide 120/240VAC just as any other house would have.  On top is a generator bypass switch in case work has to be done on the system and the inverters shut down.



The next picture shows some of the additional "stuff" that you would need with a larger system.  The white box in the center of the pictures is the main DC disconnect along with several DC breakers.  The black box just above it is the MPPT charge controller for the solar array.  The white box just above that is a PWM charge controller that manages excess power by "dumping" power to a heater element in a secondary hot water tank (used a pre-heat for my domestic hot water tank).



This is a picture of my solar array and wind turbine.  The wind turbine is a 1kW SouthWest Wind Power Whisper 200 (no longer available).  The turbine sits on an 80ft tilt-up tower.



This is a picture of the charge controller for the wind turbine.  Built-in is a heater element that will dump power if need be (which is why it is labelled "hot").



What I don't have pictures for are my 7.5kW diesel genset and my experimental solar array.  The diesel generator was originally wired to automatically come on when the batteries reached a certain depth of discharge.  At the moment that has been disconnected because of my on-going efforts to try to bring the shop into the system.  Also not shown are the hundreds of feet of copper wire of various sizes buried and criss-crossing my property.  :D

The "dump" loads are necessary to manage excess power (i.e. when the batteries are full and you still have sun and/or wind).  If you generate it, you either have to use it or dissipate it.  Since you are your own power company you always have to balance load with generation.  I have three levels of dumping - two involve the hot water tank, and the third is the wind turbine heater.  All have settings that need to be harmonized.

To further complicated things, my shop runs on both 3-phase (25kW) and single phase (7.5kW) generators.  Someday, money and time permitting, I would like to set things up to power both the single and three phase loads using solar.  Eventually even the sawmill will be powered by solar if I can manage it.  The equipment exists, but the cost is considerable.   

[Paul_H]

Very interesting,thanks.

[Jason_AliceMae Farms]

Thank you for all of the pictures and explanation.  Both the house and your system look very well thought out.  Once I sit myself down and figure out how much power and what exactly I want to do I will be sending you a PM especially knowing that you sell this stuff and are up to date with what is current.

[New Forester]

"Here are some pictures of my off-grid system" WoodenHead

That is one of the nicest, cleanest (and most expensive) private solar installations I've ever seen, and I design and install them.  Whoever did that work did you proud and if was you, I bow humbly.

The only reason to be this extravagant is having to meet a huge electrical load and the easiest way to save money on any power installation is to minimize the load.  Conservation is really cheap compared to replacing batteries.  The single best energy saving tip I can offer is insulation first.  Yea the whole house but specifically the refrigerator/freezer.  I use a 12 volt Engle (www.engel-usa.com), swing motor compressor, it draws 2.8 amps at 12v freezes 3 cuft rock solid, insulated to R40, another one chills my 5 cuft refrigerator (R30) but that one rarely runs because the freezer side does most of the work.  Total daily consumption for both, about 55 amp-hours and I have never had to suffer warm beer or lack of ice cubes for cocktails.

Hummm, as I'm new here, I should mention this f/f is on a sailboat, the entire vessel, is powered by 550 watts of solar panels and 600 amp-hours of AGM batteries, been living aboard for 9 painless years.  I made the f/f, insulated the bejezus out of it and never looked back. 

"Solar Generator" is marketing hype for a battery and inverter with a solar panel, how difficult is that?  Concentrating on energy conservation plus LED lights, tight construction, lots of insulation and a good bit of help from ya'll will hopefully lead to success in my newest adventure, a net-zero house nestled in an east Tennessee forest.  I am looking forward to the conversation ... hello.

[Jason_AliceMae Farms]

Welcome!  I look forward to following the progress on the net-zero house. 

I am pretty new here too but the folks here are very welcoming.  There is A TON! of knowledge in this great group.

[Rockn H]

WoodenHead, that's a really nice system.  I may have a few questions for you sometime.  ;) 
  A friend of mine is building a 1700sqft camp right now and is going solar with a diesel back up.  He has me looking at solar again, but while I can figure how many watts are need to carry a given load "now", figuring how many amp hrs. would be needed to carry this load for say a 24 hr period gets complicated.   He's using a company to figure his system and it's looking like $15,000.  We're planning on starting a small cabin next summer, but I can't justify the cost of solar for weekend use.   It's looking like we'll have to use a system similar to what we had on our last camp.  A battery bank and an inverter that uses a 5hp motor and a alternator to charge it. :D   With a small solar panel to keep the batteries up during the week when we're gone.   This worked good for us before, except during the summer months when it couldn't keep up with the A/C. 

[mad murdock]

One thing that can help conserve with lighting circuits is the use of joule ringers to cut power consumption without cutting lighting. They are fairly simple to make, from what I have seen on YouTube and other websites, and the materials are really inexpensive to boot. I plan on utilizing them when I start on my project. 

[New Forester]

Totally independent power systems that provide Air Conditioning are going to be expensive and is a rather poor use of energy IMO. 

These days the solar panels are cheep enough it's storage that costs.  Turning Lead and Sulfuric acid into cold air will never be efficient as there are large, cumulative losses in each transformation of energy, sun to electricity 15%, electric to chemical (battery) 85%, battery back to electricity 85%, electricity to motion (spinning motor) 85 to 90%, motion to compressed freon 80% and finally freon evaporator to distributed room air about 80% (another fan involved).  That leaves (.15x.85x.85x.9x.8) about 8% of the power hitting your panels becoming cold air at night. (note: the inefficiency of each step adds heat to the interior further increasing the AC load)

Good building design should minimize or eliminate the need for AC.  Generally the best thing about AC is dehumidification at least here in Florida.

[Draco]

I'll bite.  What building design in Florida will eliminate the need for AC? ???

[clearcut]

What building design in Florida will eliminate the need for AC? ???

Here is one featured in Fine Homebuilding in 2004.

     http://www.hoffmanarchitecture.com/finehomebuilding.pdf

I lived near Clearwater for several years. I spent one summer without AC in an older house that used similar features for passive cooling.  It was bearable, but I welcomed moving into a house with AC.

[WoodenHead]

New Forester,

I designed, put together and wired the system myself.     At the time, there was hardly an electrician that would touch the stuff.   :D

The system was rather expensive, but so was bringing utility power out to our location.  We designed the house from the ground up for power consumption of 6-8kWh/day (average home in Canada consumes about 30kWh/day).  My wife added the stipulation that we weren't going to do without any of the normal conveniences.  So, I have A/C.  Air conditioning is not a recommended load in an off-grid home, but if used strategically (i.e. when the batteries are full and the sun is shining bright) there's no harm in it.

Energy conservation is certainly the best way to save money when designing an off-grid system.  If you don't use it you don't have to generate it.  I know of one person who won the lottery so to speak and decided to disconnect his home from the grid.  He had no desire to implement any energy saving measures.  $250,000 later he is living off-grid.   :D

Off-grid systems can be built for much less, but it comes down to life-style.  The really small systems require a noticeable change in life style (for many of us).  I have one client who cooks on a wood stove and has an old water pumping windmill to provide gravity fed running water to the 1 bedroom home (plus loft).  Their power consumption is much less than mine and their system cost was much less.  It could have been even simpler, but they still wanted some of the automated features (like automatic generator start) and be able to start a 1/2 HP motor for their farm.  Everyone's needs and wants are different.