Alternative energy advice from Ask Jeff Yago. Volume #26

Ask Jeff Yago
Solar & Energy-Related Issues

By Jeffrey Yago, P.E., CEM
Jeff Yago

Sorry. Jeff no longer answers questions online

Solar array


I am attempting to bring the first Solar Array to attach to the Grid, in Pennsylvania.

I need some expert advice.

G. Price

Mr. Price:

I can assure you that you are not the first person in Pennsylvania to install a solar array connected to the grid. We have been doing this for over 15 years and many installations were in Pennsylvania. I also assure you we are just one of many solar installers on the east coast and they also will have installed many systems in your state. If really interested, check on the web for a listing of qualified solar dealers by state:

Good luck,

Jeff Yago


My wife and I are trying to be self sufficient as possible. We just paid off our house at the age of 30, got ourselves a well and a new barn on a 1/3 acre parcel with a house. We just purchased an AeroGarden PRO200 aeroponics unit and would like to put this in our new shed and grow inside there. Is it possible to power this unit, possibly two of them with solar and what would I use for a solar system. Keep in mind we are in Arizona and have basically an unlimited supply of sun, sometimes too much.

Thanks in advance



Yes you can power the AeroGarden PRO200 from a solar-powered inverter if you are willing to spend several thousand dollars to power its three grow lights. However, why are you wanting to play around with these “toys”? They are for apartment dwellers wanting to grow one tomato plant. Since you have a house, well, barn, and land, why not buy a greenhouse “kit” or build your own add-on greenhouse to your new barn?

It can be any size you want and will be totally solar powered without having to power with a separate system. This will give you much more growing area and if you do not want to heat in the winter, you can use it to start early spring seedlings without auxilliary heat. Your location should keep it very warm in the winter if you add some thermal mass like an insulated concrete floor slab and several 55 gallon barrels of water along the insulated back wall to absorb the bright afternoon sun during cold winter days. There are many passive solar books on this subject you should review and most were published in the 1970’s.

Just a thought,

Jeff Yago

Surface mounted LED fixture

I am looking for fixtures just like the one in your article Is LED lighting in your future. I have been unable to find that style. Can you tell me where to get them?

Tim Kieffer


That is actually a model that I purchased several years ago at a boating supply parts store. There are many more models and styles now available for the boating and RV world, and I suggest you try these outlets.

Jeff Yago

Transfer switch

Aloha Jeff,

I’m looking to be near off-grid in the next 5years. I presently have solar attic fans, and am pumping house water from catchment tank using a 3 gal per minute/50 psi – 12 volt RV flowjet pump (soon to be powered with solar panel and battery backup).

My question – I have a 4000 watt generator and am looking for a transfer switch for the grid/gen scenario which will eventually be solar/gen scenario. Any guidance on acquiring a single, inexpensive transfer switch which will work in both situations?

Thank you very much in advance for your attention to this question.

Frank Pustka


Of course the best transfer switches are those you can buy as an option with the larger size generators. They are expensive but well made. Most smaller capacity generators can get buy using an industrial relay having at least 30 amp capacity ( 30 amp X 240 volt = 7200 watts ). However, before trying to build your own transfer switch be sure to use a relay having a DC coil, and use an AC to DC rectifier bridge. This is because when a generator starts to wind down when turned off, it is still generating power, but as the voltage drops an AC relay will “chatter” while a DC coil will remain closed until it completely opens. This is much easier on your electrical loads downstream as you want a “clean” transfer from generator power to grid power, or inverter to generator. When the relay does not “snap” from one position to the other, the relay will not provide a clean transfer of power and will cause major voltage spikes or voltage sags to the loads downstream.

If you have no idea what I just said but still want a very-low cost transfer switch for a smaller size generator that avoids the problems I described, check out the following link:

Good luck,

Jeff Yago

Going solar on our RV

We would like to go totally solar on our RV. Any suggestions on the least expensive route to go?



This is not easy to do unless you have lots of roof area not obstructed by antennas, vents, skylights, and AC units as most solar RV systems are only large enough to meet full-time power needs. Also, powering your air conditioner unit is out of the question, so I hope your camping will be in an area that has mild weather.

If still interested your first problem to address is increasing your battery capacity. Most RV batteries can only store about one day’s electric requirements as they assume you will be connecting to the RV park each night for re-charge. I suggest replacing your single 12 volt RV battery with two (2) 6-volt golf cart batteries which will provide more storage capacity and will stand up to the heavy daily charge-discharge cycling. Next, since your RV’s battery system is not wired to any of the 120 volt outlets, you will need to add an inverter unless you will not be using any 120 volt AC appliances like a TV, computer, DVD player, or micro-wave. I STRONGLY suggest buying an inverter having a pure sine-wave output as it will provide much better service and have less risk of damage to some types of electrical loads than lower-cost modified sine-wave inverters. You will need at least 800 watts capacity to power all the electronics you may have, but you will need at least 1800 watts output to power most micro-wave ovens.

Lastly, if you stay with only the DC circuits in your RV and do not need an inverter, your RV roof may provide enough free roof area for the solar modules. However, regardless of mounting, there will be times the RV will not be oriented properly or will be in a shaded area. Since I wanted much more solar power than I could get on the roof of my RV, I have four (4) larger 75 watt size solar modules and folding ground mounting rack that I keep in the rear truck bed. It is pre-wired with a 50-foot cable and if I need to dry-camp, I can remove them and position the rack on any side of the RV to face south. If my batteries are really low, I can re-position the solar array several times during the day to always face the sun. Since solar modules are available in different sizes, you can find a size that is not too large for you to handle by yourself, but will fold up as needed to fir the storage area you have. There are several firms now providing roof mounts for solar modules that can be remotely raised and lowered or even rotated, but your power requirements may exceed the amount of solar array these can handle.

Good luck,

Jeff Yago

Wood fired hydronic furnaces

Hi Jeff,

I have just stumbled upon one of your columns while researching boiler options for our home. It is a 3000 ft2 log and stick frame home in the woods (read: unreliable power), with additional heating for a 1000 ft2 insulated work shop, a few walkways and porte-cochere (snow control only). We have completed extensive renovations and the heating system was upgraded to radiant floor (multiple zones) from an oil-fired scorched air system.

My question goes toward more reliability and longevity than efficiency per se. There is ample fuel in the form of hardwood available, and I don’t mind a little extra of the cut-split-stack routine so a few percentage points in efficiency I can live with assuming there is not a huge increase in particulate emissions. What I would like to avoid, however, is spending a lot of money on a WFHB and have to repeat the process in a few years. I originally looked at models by central boiler but have heard many horror stories about their fire boxes being destroyed after 5-7 years, and am leaning more towards ceramic lined ‘gasification’ units such as the Greenwood.

Can you offer any advice in this matter?

Many thanks and best regards,

Tom Tebo


The last time I tried to recommend a wood-fired heating system to a reader I had a dealer for corn stoves writing irate email to me for months saying his system was better and I should have included it in my article. Having said that here we go again.

I have a wood-fired hot water boiler that heats my 3400 square foot home that includes a welded steel water jacket around the sides, back, and bottom of the fire-box, plus 90 feet of boiler tubing above the fire-box. Water flows around the fire and is piped back to a hot water coil in my forced air furnace, which distributes the heat to every room. I purchased this unit in 1978 and it was in storage until I built my home in 1993. Although we do not build a fire every night during the winter, we do use it as often as I am home to carry wood and we have never had any problems with burning out the fire-box or water jacket since the water keeps the steel below 200 degrees. We just had our chimney cleaned this past fall for the first time since moving into our solar home in 1994 and the chimney sweep said there was only minor buildup on the interior flue walls.

I have not heard of any major increase in wood-boiler fire-box failures and find this hard to understand unless these failures were related to metal parts not enclosing water and over-heated. Like any marketplace of different products having different features, each manufacturer will say their products are better than the other brands and list all their selling points. I know I would not want any appliance in my home that was burning at over 1100 degrees even with a ceramic lined fire-box, but I understand that these higher temperatures can improve burning efficiency and reduce chimney buildup. Keep in mind you are wanted to heat your home with radiant heated floors and this requires a much “lower” water supply temperature for heating then if you were heating with hot water radiators or hot water coils in a ducted air system.

I am sure almost any of these systems will serve your purpose, so I would select the brand with the best warranty and best installer who will be there if you do have problems. When shopping for any wood stove, I am always interested in how long the fire-box is so I can see how short the wood must be cut, how large the fire-box is so I know how often I have to re-fill it, how are the ashes removed, which is always a pain, and what kind of simple controls are provided to automatically regulate the burning process. I want a wood stove I can fill up and then leave it alone for hours without having to constantly adjust something.

Good luck,

Jeff Yago


Hi Jeff:

Are you familiar with the vertical wind turbine generator used by celebrity Jay Leno in his power system, and what is your opinion of the vertical turbines in general?

Efficiency vs Cost? Finally, what manufacturer would you recommend?

Thanks for reviewing these questions, and for the great articles in Backwoods Home.


Andy Anderson


If you ever got several private pilots together and asked which is better, a high wing or low wing plane, you might end up watching a fist fight. I have seen a few applications where vertical axis wind machines were a good choice, but almost all commercial wind systems are horizontal axis machines. I just drove through eastern Pennsylvania today on my way back to Virginia, and I counted over a hundred large scale horizontal axis wind machines lining several ridge lines. Since each one of these cost several million dollars, I assume someone smarter then me has figured out these horizontal axis designs are a good choice. It is also easier to support the blades and mount at a high elevation above the ground where the wind is highest.

Hope this helps,

Jeff Yago

PTO Generators

Hi Jeff,

New to the website I love what I see and sure enough will be back many times.

I just purchased a Kubota BX24 diesel tractor and I am now looking into setting my house up with a back up PTO Generator. The PTO runs at 540 RPM with appox 17.5 hp at the rear PTO. Can I run effectively a 11-15 KW generator off this PTO? Second I am also wondering if I run this tractor at 1800 rpm will the PTO still run effectively? Thank you for you time and consideration.

Best regards,

David Petricone


Nice tractor! Yes, you should be able to power most of your home’s loads during an emergency, if you select the right generator. I had a recent client living off grid who was using a tractor-driven generator to re-charge his battery bank on the days his solar output was low. However, he was having all kinds of problems and was blaming his inverters. He wanted us to send his two inverters back for factory repair. After checking his system, we found the problem was his low cost PTO generator had very poor power regulation which was causing the inverters to keep dis-connecting due to an out of spec voltage and frequency.

A 12 to 15 kW generator will be large enough for most residential applications, and should not overload a 17 HP diesel PTO. All PTO designed generators have built-in gear boxes that take the standard 540 RPM input speed and increase it to what is required for the specific generator (usually 1800 RPM). If your generator includes a high quality power output controller, this will hold the voltage output fairly constant even if the speed varies up or down.

Good luck.


Inverter for solar powered trailer

Dear Jeff,

I have ordered a trailer, and am in the process of replicating the one you built.

In researching inverters, I contacted Xantrex, intending to find out what I could about a ‘true sine wave’ or the SW series. They have discontinued them; it was recommended to me to use a Prosine 2.0, but the individual who responded did not seem to be aware of any application for a mobile trailer…in fact, also recommended a replacement for the SW series that was for residential use, and said that ‘modified sine wave’ inverters were being used by their customers for computer power. I suspect that there is some additional conditioning for a residential application between the inverter and the computer.

Since I would like to be able to power anything in my house that the trailer will provide adequate power for, are there current units in production you could recommend? Not being an electrician (just a jack of many trades), I intend to almost exactly duplicate your trailer (using a smaller fridge, and a Honda generator i already own). I am trying to avoid ‘overbuying’ or mistakenly getting some part that will not work.

Thanks for any help and/or advice you can give :) I thought your trailer was a brilliant idea…2KW of power in a complete outage (which we get from time to time) is far preferable to ‘no KW’…i have an American Ingenuity dome house-approx. 800 sq ft on lower floor, and putting panels up would be a nuisance, not to mention the problem with battery storage area.

Elton Wylie


Glad you liked the article. You are correct, the SW series sinewave inverter line has been phased out and many of us are sad to see this guy go as it is the only inverter out there for small applications that came standard with two built-in automatic transfer switches – one for grid power and one for backup generator power. Xantrex has replaced this product line with their new XW series inverters. These are really great, but are definitely high dollar products for larger residential grid connected, grid-ties, and off-grid applications.

Most modified sinewave inverters will power a computer without any problem, but some appliances like a microwave oven will not heat very well and some televisions may have a reduced screen size when powered from a modified sinewave inverter. I actually had some X-10 type remote controlled light fixtures have a melt-down when powered from a modified sinewave inverter, and X-10 wall switches that actually were hot to the touch. Some battery chargers do not charge properly when powered from a modified sinewave inverter. Although they cost more, a true sinewave inverter is your best bet.

However, having said all that, my article describes the system I built using a sinewave inverter from Outback, not Xantrex, and the Outback sinewave inverter line is still going strong with several sizes to pick from.

Check out

Good luck,

Jeff Yago

Safe LED Lighting


I read the article on LED lighting in the most recent Back Woods Home magazine and I have a couple of questions for Mr. Yago:

Do these lights have mercury in them, and if so, how can these lights be disposed of properly so they do not adversley affect the environment? And, what about the radiation that these lights emit? I have read many times that the LED alarm clocks should never face directly towards one’s bed as they emit low doses of radiation. This is a real concern for me as I realize that so many of the electronic gadgets we use emit radiation and I wonder if over time we will see more cases of cancer and other illnesses due to this radiation exposure?

Thanks for a great magazine!

Lori Smith


Not to worry, there is no mercury in an Light Emitting Diode (LED) lamp, but there is mercury in Compact Fluorescent Lamps (CFL). The only radiation an LED lamp projects is light energy, no radioactive radiation like you are concerned with.

The older style clocks did have their glow-in-the-dark hands coated with a phosphorescent paint, and years ago they did use a very low radioactive type material. Since radiation travels in a straight line, turning these clocks away from you would be a good idea. However, much tighter regulations has forced most of these products to switch to non-radioactive and safer materials.

Perhaps you need one of those talking alarm clocks!

Jeff Yago

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