I Should Have Expected This

At the 1979 total solar eclipse, I watched it from a location right next to some electric power distribution equipment.  Just as totality hit, there was an enormous flash from the equipment, as (presumably) thousands of photosensors turned on lights.  Along with what sound like irrational disaster fears in many states on the totality path, this 8/7/17 CBS Philly article has a video about how the partial eclipse is going to drop 6 megawatts from California's photovoltaic grid, requiring backup power sources to come online.

Battery/Charger Question

I have a solar charge controller charging a 12VDC AGM battery from a solar panel.  The controller has two LEDs: charging, and charged.  The charging LED is pretty much always on while sunlight hits the panel.  The charged LED never turns on.  The battery is certainly charging; I have an inverter connected to the battery and I can turn on the inverter and run AC lights, even at night, so I know the charge controller isn't powering the inverter.  How should I determine the defective part?  Would taking the battery to a dealer enable them to determine if the battery is ready to be replaced?  How do you verify that charge controller is doing it right?

Solar Power Made Easy

This company sells a solar system that instead of requiring an electrician, you just plug the output of the inverter into an outlet.  I asked the following questions:

1. Will the power going into that circuit cross the breaker and feed other circuits?  YES.

2.  Will the 110VAC going in that outlet feed 220VAC devices on other circuits?  NO.  Ask for the 220VAC inverter, plug into a 220VAC outlet.

3. Will the 220VAC input into the 220VAC circuit cross over to the 110VAC circuits?  YES.

4. Does the grid-tie require an electrician to install?  YES.  The ones that just plug into an outlet are not grid-tie and do not.  They is a grid-tie option.

The price is higher than more traditional solar systems, but it does seem to be entirely DIY.  I might hire my ex-Special Forces handyman to put the panels up.  They also sell backup/off-grid systems.  Amazon sells the more expensive systems only.

LED Bulbs

I was so happy with the first set of these:

that I ordered more. The master bathroom vanity had five 52 watt incandescents (mostly because of heat concerns) so replacing them with these has transformed the room.  Far more light for shaving and applying makeup, and much whiter (like daylight).  And even with the dramatic increase in illumination, I am using 1/4 of the electricity. 

When I tried putting the LED bulbs in the outside security light fixtures, the lights flickered.  Some pages I visited suggested cleaning the inside of the socket to get a better connection, or see if all the electrical connections to the fixture were good.  So I wiped the interior of the socket (with power off), then removed the fixture from wall, where I found not wire nuts, but some other type of connector that looked far too solid to easily disassemble or suspect.  I now wonder if the issue is that these lights are so bright that they are turning off the light sensor of the fixture for a fraction of a second and when darkness arrives, the power goes back on.  This may require some tuning of the fixture's light sensitivity.

Solar Power

Last year, before the heart attack and stroke, I was experimenting with PV panel, a solar battery tender, a 12V battery, and a Harbor Freight inverter in the telescope garage.  I was successfully recharging the power supply for the telescope mounts.  Then all my time was spent trying to get my life back.  I decided to go see if all the parts could be used to run a 14W LED bulb.  If so, I would put a light fixture on one of the rafters, run some Romex to the power inverter and a light switch, and at least have light in there.  The bad news is that the battery with the misleading name MaxLife is 17 months old and will not take a charge, even from a battery charger hooked up through my 100 foot extension cord to the house.  Also, the solar battery tender no longer seems to work.  Even with power from the solar panel, output is 0V, and the status LED on the tender is utterly dead; it also will not do anything to the backup Jaguar's battery, which is just fine.  I think I will get a fresh battery and charge controller and try again.  Solar power barely make economic sense, because of the capital required, but for a structure that has no power lines to it, this makes sense.  The cost of excavating a trench for power and installing a circuit breaker panel makes this sort of DIY solar make sense, especially because I have the PV panel and the inverter already.

Solar Power Again

I am looking to install a couple of 225W 240VAC panels on the house, not grid-tied and not charging a battery, just to provide excess power for summer A/C and another source of power in the event of the end of civilization as we know it.  I am waiting for some technical details on cable lengths and mounting brackets.  I do want to order them to get the tax credit for this year, when I will have some shot-term disability income that wasn't taxed.

Nice to See More Solar Power Innovation

The end of tax year 2014  is coming soon so if im going to install solar panels I better get it done before the end of month. I was looking on Amazon and I was pleased to see that someone has simplified the installation process a bit more. This package is a 235 Watt solar panel that plugs directly into 120 V AC outlet. It should just be something that you can on the roof and plug in. And the price is $795.

Solar Power Finally Makes Sense--Even Without the Tax Credits and Deductions

Here's the spreadsheet:

This involves buying this 400 watt system, which includes a 1000 watt pure sine wave inverter and 30 amp charge controller, cables, and mounting brackets.  It does not include a battery, which I really don't need since the goal is not to become completely independent of the grid.  It would, however, provide enough power to keep the well pump and pressurization pump running at least part of the day.

My assumptions, based on my experiments with solar panels at my location over the last few years, are 3.5 hours of full sunlight in winter (we get snowstorms, but many days of clear blue skies that are below freezing), 7 hours in spring and fall, and 10 hours in summer.  I am also assuming that the current Idaho Power electric rates are not going to drop.  The Idaho income tax deduction is 40% of the cost first year, and 20% for the next three years.  Strictly speaking, treating this as 100% first year is wrong, but inflation isn't so high as to make this too far off.  I am assuming that the costs of having my neighborhood electrician install this to my breaker box are not going to much at all, and I will install the panels on the roof myself.  I am assuming that the system will net 100 watts per panel, even with inverter losses, because a number of buyers of this panel report actually measuring 120 watts per panel.

Notice that it pays for itself in less than two years, and even without the tax benefits, in less than three.  (Tax credits can hide a host of bad ideas, but in this case, it makes sense.)  It looks like it scales pretty linearly if I install more equivalents in future years.

The primary goal is to reduce dependence on the grid, but it at least seems to make sense as well.

UPDATE: The 400 watt system above includes a charge controller (which I don't really need).  I might get the cost down by $30 by purchasing the inverter, cables, and mounting brackets with the panels separately.

UPDATE 2: In case you are wondering why this kit includes a charge controller but no battery, I suspect that it is because enough deep discharge battery to store very much of this power would take the price way, way up there. It certainly makes it nice to be able to just add as much battery as makes sense for you.  This 28 aH battery would store 336 watts--less than an hour of output from these panels (assuming no losses in the wiring and perfect output from the panels).  The cost of enough battery to store several days energy production is as much or more than the 400 watt system, which is an argument against using batteries unless you are seriously interested in getting off the grid on a regular basis.

UPDATE 3: The panels alone are about $600.  This 400W pure sine wave inverter is $144.95.  With the cables and mounting brackets, this could be done for about $800, which knocks payback down to a year and a half.

UPDATE 4: I am waiting to talk to my electrician, but I suspect that I am going to need a 220V inverter to feed power into the bus on the panel.   To my surprise, while pure sine wave 220V inverters are rarer than 110V inverters, they are not dramatically more expensive in the same wattage range.

UPDATE 5: I just can't take seriously an inverter with eye candy in the picture.

Solar Power

I see that our power rates have increased recently.  The non-summer rate is now 7.23 cents/kWh; the summer rate is now 8.5 cents/kWh.  (You Californians have no one to blame but your state legislature.)  This means that the 100 watt panels that Amazon has for $150 each would pay for themselves (even ignoring tax incentives) in about 60 months or so. 

Solar Power

I bought a cheap modified sine wave inverter at Harbor Freight, 400W continuous, 800W peak, primarily for experimental purposes.  If I end up putting in a garage door opener, I'll use a pure sine wave inverter for that circuit, and this one for lighting.  And it works.  I plugged in a CFL lamp, and it worked.  Next I plugged in the charger that recharges a telescope battery pack/flashlight combo, and it recharged it pretty quickly.

Next step: installing a couple of light bulb fixtures in the ceiling of the telescope garage (using LED bulbs to reduce power consumption), a wall switch, and starting to run electrical conformant to the building code so that I can plug in one or two circuits to the inverter.

Pure Sine Wave Inverters Are Astonishingly Expensive Compared to Modified Sine Wave Inverters

I am guessing that there is something about the electronics required to produce a pure sine wave that explains the astonishing price difference.  As I understand it, if you are running a computer or other digital device, a pure sine wave AC output really matters.  What about other devices, such as garage door openers, electric motors, drill presses?  Is there any advantage to a pure sine wave inverter over a modified sine wave inverter?

More On Solar

One of the great frustrations there for a while on solar power was that if you bought enough of a charge controller to handle a really big array, then you were spending a pile of money for a charge controller.  If you wanted to start small and build up your solar panel array, you could save money by buying a small charge controller, but then you would have to upgrade it.

I am not immediately sure of the output capacity of the Battery Tender that I currently have at work in the telescope garage, but I suspect, based on the current version of it, that is probably 9W or 10W.  That isn't going to work if I want to add a 40W panel.  I know that there are problems if you try to combine two different power output panels to a single charge controller--often you end up with the lower output panel limiting the output of the higher output panel.  But I presume that it is possible to feed the output of two different charge controllers into the same storage battery -- or do you end up with that same problem of the lesser source limiting the greater source?  Or is it necessary to use a diode to prevent power from working its way back from the battery to the other charge controller?

Because of the manner in which I will be using these, it might just be simpler to use the low output system for lighting, and the high output system for running an automatic garage door opener.

Solar Power in the Telescope Garage

I had mentioned a couple of months back that the 5W solar panel that I bought for solar power inventions a few years back seemed to be dead.  I went out to the telescope garage this afternoon, and discovered that it was apparently a problem of having the polarity to the battery minder wrong.  Once it was in direct sunlight after the polarity reversal, the tender showed that it was charging the 12V battery.

Measuring the power output, I found about 1.8W, which reflects what I have long suspected: that Harbor Freight's specifications on products may have a wide range of output.  Or perhaps it was because it was late afternoon.  On the other hand, at 8:20 PM, the battery minder still showed that it was charging the battery.

UPDATE: Never assume that your components work.  It was kinda Rube Goldberg, but attached to the battery terminals I put a alligator clamp to cigarette lighter adapter, then a 12 VDC cigarette lighter plug to 110 VAC converter, then I plugged in a lamp with a CFL bulb.  And nothing.  But after testing each component, I discovered the 12 VDC -> 110 VAC converter (originally purchased for a 2001 East Coast trip to recharge the Hi-8 camcorder) no longer works.  It would not power a cell phone recharger, for example. 

Of course, I don't have a 12 VDC light anywhere to try on a direct connection, but if I get serious about powering lamps, I am going to need something that does the 12 VDC -> 110 VAC conversion in a way that gives more than just one plug.

Solar Power Calculator

A reader pointed me to the National Renewable Energy Laboratory PVWATTS 2 calculator, which uses your local weather information to calculate likely power output, including adjusting from nominal DC output to AC (because of inverter losses).  I ran the data for a nominal 1 KW system (four of those Westinghouse panels), using the default inverter efficiency, and our current 7.8 cents/KW-h.  I also assumed a fixed tilt array.  (Changing the angle four times a year helps, but not dramatically.)  I am not assuming that I will get my proprietary improvements working.

"Station Identification"
"City:","Boise"
"State:","Idaho"
"Lat (deg N):", 43.57
"Long (deg W):", 116.22
"Elev (m): ", 874
"PV System Specifications"
"DC Rating:"," 4.0 kW"
"DC to AC Derate Factor:"," 0.770"
"AC Rating:"," 3.1 kW"
"Array Type: Fixed Tilt"
"Array Tilt:"," 43.6"
"Array Azimuth:","180.0"

"Energy Specifications"
"Cost of Electricity:"," 7.8 cents/kWh"

"Results"
"Month", "Solar Radiation (kWh/m^2/day)", "AC Energy (kWh)", "Energy Value ($)"
1, 2.88, 276, 21.53
2, 4.16, 359, 28.00
3, 4.93, 463, 36.11
4, 5.77, 507, 39.55
5, 6.12, 542, 42.28
6, 6.47, 541, 42.20
7, 7.05, 582, 45.40
8, 6.93, 587, 45.79
9, 6.40, 536, 41.81
10, 5.30, 481, 37.52
11, 3.48, 313, 24.41
12, 2.80, 272, 21.22
"Year", 5.20, 5459, 425.80

I should point out that the 7.8 cents is for the 0-800 KW-h consumption rate -- Idaho Power actually charges us more than that above 800 KW-h per month.  Sixteen of those panels would cost $9600 plus shipping; I am going to have to pay something to my electrician to put in a 20 amp breaker to connect this to the main bus.  I will also have to spend some money and time build a support system to position these on the hillside that allows me to change angle four times a year.  Still, it is hard to imagine that this plus shipping will exceed $600.  A $10,000 investment thus takes 23 years to pay for itself, ignoring rising electricity prices and leaving out the 30% tax credit from the federal income tax return and the relatively trivial tax deductions on the state income tax return.  It also does not include the inevitable drop in output over the life of the panels.

This is beginning to make less and less sense.

UPDATE: Of course, if the cardiologist calls me back next week and says that I need an angioplasty, all of this will need to be delayed.

UPDATE 2: This isn't California.  Idaho Power's net metering program is somewhat limited:

Is there a limit to the size of generation from the customer? 
Yes. For residential and small commercial customers, generation is limited to 25 kilowatts of nameplate generation or less.

I am guessing that they mean 25 KW-h per month.  Not a problem; I can't imagine investing that much capital in solar panels.

Is there a limit to how many Idaho Power customers can participate in Net Metering? 
Yes. At this time Idaho Power limits the total amount of customer-owned generation to 2.9 MW. The actual number of systems will vary depending on the size of the individual installations. 

I have no idea if they are at limit yet; I've put in a call to their office to find out.  Worst comes to worst, we skip net metering and just settle for wasting the extra energy. Perhaps this would encourage not putting in more panels than I would likely use at any given moment.  Or it might make sense to look at using excess power to charge batteries for use after dark.

UPDATE 3: Details on Idaho's alternative energy tax incentives are here.  You are allowed to deduct 40% of the purchase price of the system in the first year from your income taxes, and 20% in the following three years.  Idahoans who can afford to consider alternative energy are going to be in the 8% marginal state income tax bracket, so a $3000 investment means a $1200 reduction in your taxable income, or about a $96 tax reduction the first year, and $48 tax reduction for the next three years.  The website previously linked isn't very clear on how the $5000 maximum incentive per year, $20,000 maximum incentive total, works; Idaho Code 63-3022C gives the details.  It appears that you are not allowed to take more than $5000 of deduction in any year.  The Idaho Code says nothing about a $20,000 maximum incentive.

If you are a greenie, Idaho law is a sign of what a backward, primitive, stingy state we are.  If you are anyone else, they are a sign that Idaho legislators like the idea of alternative energy, but didn't drink the green Kool-Aid.  The incentives are so tiny that they are essentially a sop thrown to greenies to make them think that Idaho cares about Mother Earth.

Simplifying Solar Power

One of the big problems that I have with solar power is that installation is typically half or more of the cost of a photovoltaic system -- turning what might be a temptation into a "this doesn't make sense" situation.  Worse, if you want to just experiment, by putting in a couple of 200 watt panels to see how much you are getting, those installation costs make it absurdly expensive.

There are several companies that are producing what are intended to be DIY (do-it-yourself, or disaster-is-yours, depending on your competence) solar systems.  Westinghouse, for example, has this panel with an integrated mounting system and inverter, as well as simplified connectors.

What is pretty interesting, however, is how some companies are producing plug-and-play products, like this Goal Zero 1250 watt-hour solar generator over at Lowe's.  It is a combination of two 30 watt solar panels with inverter and deep discharge battery.  This isn't intended as a primary solar power system, but as an alternative to a backup generator.  The two 30 watt panels are supposed to fully charge the battery in 20-22 hours, or you can recharge from the grid in 16-20 hours.  When fully charged, it gives you 1250 watt-hours -- which for short-term emergencies is probably sufficient.  They also claim that you can add more panels to reduce charge time, or add more deep discharge batteries to increase capacity.  And it is all portable.  For $1799, this doesn't seem like a bad product idea.

The Westinghouse Instant Connect 235W panel is available for about $860 on eBay (including tax and shipping).  That's not a particularly impressive price if you are only looking at the dollars per watt, but it does include the inverter, and I guess that you could just plug it into a wall socket.  I believe that our backup generator already has a grid disconnect built-in, so something like this would be a plug-and-play device.  This wouldn't run our power meter backward without net metering equipment installed, but in the heights of summer, when our electric utility bills are high to pay for air conditioning, this would make a lot of sense.

UPDATE: Reading the DIY installer instructions for the Westinghouse give me pause.  They are still written for an electrician.

A reader points out that he suspects air conditioning costs are a big chunk of the average household's electricity use.  I suspect that he is right, at least in summer.

There is an amusing synergy here: air conditioning is a big cost in areas where solar energy is most available and reliable.  When solar energy is not so available, air conditioning costs drop nearly to zero.  In addition, electric utilities charge higher electricity costs above some threshold level, so even in places where solar power as a source for all your electric power might not make economic sense, solar power might make sense for getting your electric consumption down below that threshold.

UPDATE 2: An email from Westinghouse Solar indicates that the pricing will be back on the website shortly, and at about $600 per 250 watt panel.  This isn't really a bad price, considering the panel has its own AC inverter.  This is cheap enough that it should call my electrician and find out what he would charge to do the connection to the breaker panel.

UPDATE 3: I was just paying my electric bill this evening.  My consumption last month was 680 KwH, or about 22 KwH per day.  At the peak of last summer, we were consuming 41 KwH per day; in the depths of winter, about 29 KwH per day (with spring and fall generally less).  A nominal 4 Kw system operating 12 hours a day (pretty typical around here at the height of summer) would produce enough power to satisfy all of our needs.  In winter, we might average 4 hours a day, or a bit less than half of our needs.  Spring and fall would produce about 25-28 KwH per day, a bit more than we need.  Of course, that would mean 16 $600 panels, or $9600.  With the 30% federal tax credit, and the fairly minor state tax deduction, that means a net cost of about $6500.  I would expect to see our annual electricity bill fall from about $700 a year to perhaps $150 a year.  That would mean about an 11 year payoff at current electricity rates -- and a bit less with the likely rise in electricity prices.

Time to call my electrician, and find out what he will charge me to hook this up.  I could start with two panels, and perhaps add two panels a month once the fall semester starts.