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Ask Jeff Yago
Solar & Energy-Related Issues

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


A tour?

Would GREATLY enjoy a "tour" of the "palace" - I am SURE that the 2 dimensional pics don't do it justice - would there be a possibility to see the place?

Myron Flagg

We get tons of requests each year to tour our solar home and we cannot possibly accommodate everyone. Our home is part of the lecture series for the architect and electrical engineering students at three different area Universities, plus the gifted children's program for our county. This means we have on average over 300 students per year visiting in groups of about 20 per field trip, and that is all the disruption to our home life my wife will allow!!

Jeff Yago


Fuses for 12 volt systems

Jeff:

I've been following your articles at Backwoods Home and have found them very helpful and informative.

I've installed two simple solar/battery systems for family at our weekend cabins in a remote area of New York's Adirondack Mountains, far from the grid. At the suggestion of the local Battery Distributor, I'm using two six volt golf cart batteries (350 amp hour size) wired to produce twelve volts (series, or parallel, I'm not clear on the proper terminology), connected to a 2000 watt Coleman Modified Sine Wave Inverter. My system has a single 75 watt solar panel; my brother in law's place has two 75 watt panels, but otherwise all other components are the same. I installed 15 watt controllers in both systems.

Both systems have gas powered generators as back up and to re-charge the batteries if needed.

I assume I should have a CD disconnect and/or a fuse somewhere in the system, but I do not. From reading your recent article, I'm not sure exactly where, and how, one should be installed. So, my questions are as follows:

1. Should some type of fuse be installed between the solar panel and the controller? The controller and the batteries? In the cable that connects the two positive terminals on the batteries? Between the batteries and the inverter?

2. While the battery bank on our little cabin seems to meet our needs, (we don't watch any TV), my brother in law has young children and their use of a VCR to watch movies runs his bank down fairly quickly. (The inverter cuts out when voltage drops to 10.8) If we add two more six volt batteries as outlined in your article to bring his capacity up to 700 amp hours, are their any additional fuse installations to consider?

Thanks for your help!!

Bob Alexander

That's a lot of detailed questions for a system that I cannot see how its wired! If a solar array is mounted on the roof of an occupied home, it must have a DC ground fault circuit breaker between the solar modules and the charge controller. This can also serve as a service dis-connect when working on the array. You should also have a DC rated fuse or DC rated circuit breaker on any positive (+) cable connected to the battery positive (+) post.

Since fuses are harder to remove, you can use a DC rated circuit breaker in each of these circuits to make it easier to shut down for service. Automotive type fuses are not UL listed for residential wiring and AC fuses and AC circuit breakers are not safe to use on DC circuits. Use only DC rated equipment that is also UL labeled.

The location, sizing, and rating of each fuse and circuit breaker is critical for the safety of your electrical equipment and your home. These comments are general in nature and I suggest that you have a licensed electrician check your work if in doubt.

Jeff Yago


Convert my car to alternative energy vehicle

Hi Jeff,

I just bought a brand new Mazda v6.

I realize that I made a huge mistake and want to somehow convert the brand new vehicle into an alternative EV. Do you have any pointers (do-it-yourself/something that can be done in a local garage) I am a computer programmer without much hands-on experience on electrical equipment. but I learn pretty quick.

Would appreciate any helpful pointers/links in this direction.

Thanks!

[Name withheld]

Some vehicles are easier to convert to electric than others. Most electric conversions require removal of the engine, finding an adapter and electric motor that will mate up to your existing transmission, replacement of dashboard controls, and re-enforcing an area for the batteries. Due to the "hacking" on the body that will be required to make these things fit, I would not start out with a brand new vehicle.

Keep your new Mazda and shop for a 10 to 12 year old vehicle in good condition but being sold at a low price due to a "blown" engine. Look for light weight but with a strong frame and suspension system. Many successful electric conversions have started with a 10 year old Chevy S-10 pickup or Ford Ranger.

Check the following sources for more information:

Electric Auto Association, Mountain View, Calif. 800-537-2882

"Build Your Own Electric Vehicle" text by Bob Brant

Jeff


Small Gas Turbines

Jeff:

There are a number of small gas turbines available. How efficient are they, how does one connect the turbine output to a residential meter box, without triggering a variety of municipal and utility company infractions and for economic reasons, how much do they typically cost?

Another vector: what is the startup maintenance schedule that is typical for one of these units? What are the ventilation requirements for exhaust, screens for intake orifice?

Sure would like to know

Syd Mead

Most states have passed some form of "buy back" legislation to allow homeowners to install their own solar or wind energy system and sell excess electrical power back to the utility. A DC to AC inverter ties the solar or wind output to the grid, which must be UL and IEEE approved to make sure power cannot be back fed into the grid during a power outage.

Its very hard to generate electricity cheaper than what the utility can sell it, unless your generator is using "free" bio fuel or you are doing co-generation with the waste heat of the turbine exhaust being used for space or hot water heating.

Most turbine exhausts are very hot and they require lots of ventilation and combustion air. This type of information is provided in more detail by the manufacturer for their specific equipment requirements.

Jeff Yago


Free energy from a car?

Greetings, Jeff

Here in Pa. I currently drive my Diesel Mercedes for free on FREE Waste Vegetable oil from restaurants. Next winter, I am going to heat my house for free.,maybe by converting a coal stove into an oil stove. But for now, I am going to supply electric to air condition my house for free. I am going to utilize the space where the air conditioner compressor was mounted in my Mercedes. I will fabricate a bracket to hold the generator head. Maybe use a 12 volt clutch devise to power the head when needed. I will then feed this power to my house where I already have the whole transfer deal set to go for my gas genset which I converted to run on LP. I will then park the car about 50 feet from the house under a nice shade tree, and start 'er up.

I intend to run it 24/7, at least during the expensive electric summer-rates time. I have 2 computers on line, one 220 volt well pump, and maybe 2 TV sets on at once. And of course, 4 air conditioners. 3 @ 5-6000 btu (6 amp each) and 1 @ 8000 btu (9 amp). total of about 28-32 amp semi-continuous, and the occasional well pump at 6? amps, 220 volt.

So, I was considering a head somewhere around 8KW, 50 amp., or just a 5500 W unit to run just the air conditioners. And depending on size, maybe 10 KW. I assume that the control panel on some of those can be removed and wired directly. Remember, I have to fit this baby where the compressor was, or make a removable bracket so I can take the car for a ride. So, what do you think?

And, have you ever heard of this type of free energy making? Let me know what you think.

Any 12 volt generator that could fit in an engine compartment where the AC compressor had been located will be fairly small and belt driven. Even if you can run your car 24/7 for free, only a very small amount of the engine load can be transmitted through one or two small fan belts to a small alternator or generator that is small enough to fit. That means most of your engine's power output and fuel consumption will be wasted. To supply the loads you are planning would take a much larger generator and drive system.

Of course you could easily provide all your power needs if the car engine was removed and had a heavy drive shaft out the transmission driving a large PTO type generator like the farmers power with their farm tractors. However, this means you no longer have a car! Look at a generator in this size range and you will see at least a 1" drive shaft. In addition, most of these generators have very light shaft bearings as they are intended for direct shaft end to end coupling. Many are not designed with bearings that can take the high side pull on their shafts when belt driven. I don't see all this fitting under the hood!

Suggestion.... Find a used 15 kW diesel generator, add your bio fuel system and very large muffler, and run your house full time in the summer and keep your car for transportation.

Hope this helps,

--Jeff Yago


Solar help for those without a clue

I am looking at buying a house that is solar powered. Since the house is so far out there are no way to have electric lines brought in. I love the place but I'm nervous. My question is. How dependable is solar power? I mean will it run most electric items without troubles?

David

The answer depends on the location and what you want to power. First, if the home is either at an elevation or location that still gets lots of sun but does not require air conditioning during the summer, that is a plus. Also, if the house has a propane or fuel oil tank that provides fuel for space heating, hot water heating, and the kitchen cooking, that is also a plus.

This means your solar power system is only powering lighting, audio/video equipment, and maybe well pumping which will require a much smaller solar power and battery system. If you want the solar system to power large loads for long periods of time like an air conditioner, central air handling unit, and any appliance or device that includes electric heating, than prepare to spend more money than your cabin cost for a very big and complex solar power system.

You should not have any problem for many years with a well installed solar array, and the inverter/solar charger equipment available today is very reliable. Our system has operated 24 hours per day for over 11 years without any problem. However, you will need to do some quarterly maintenance on any battery bank and these will need to be replaced every 4 to 8 years depending on battery type and size. Solar power for remote homes and cabins is starting to be much more common than you think, and if you are moving to an area without electrical service, you may find neighbors doing the same thing.

--Jeff Yago


Battery question

Dear Jeff,

In most of your articles you recommend the L16 6V batteries. Is there a reason these are preferable to 12V batteries? Also, what batteries would you recommend for setting up a 48V system? I'm in the process of setting up an 8KW generator to charge a bank of batteries. I will be using a Xantrex (Trace) SW+ 2548 inverter and 2 Trace C40 charge controllers, adding solar panels down the road.

JD

Most non industrial 12 volt batteries you will find need to keep the lead plates fairly thin to pack six 2 volt cells (12 volt) into a single battery case. Thin plates cannot take the heavy charge/discharge cycling in a solar power application. A 6 volt battery is almost the same length and width as a 12 volt battery, but since only three 2 volt cells (6 volt) are used, the plates in each cell can be twice as thick.

The "L16" size industrial battery has been around for many years for use on battery fork trucks, mine transport cars, and battery powered floor cleaning machines. It is designed for very heavy daily use and although it is much heavier than a car battery, it can still be easily lifted by two people. The next size up battery requires a hand truck or lifting equipment to move, which is not always possible inside homes or on remote sites.

Since this is a 6 volt battery, your 48 volt battery bank will require 8 batteries in series, or 16 batteries with 2 strings of 8 batteries. If you need more battery capacity than this, I would suggest switching to a larger amp-hour rated industrial battery and use fewer batteries.

--Jeff Yago


Old New England Victorian

I live in a suburb of Boston, Massachusetts in a 100 year old Victorian style home. I currently heat with oil and with oil prices rising, I've been thinking of supplementing with some kind of solar. One side of the house faces south with no trees or other obstructions. The house has about 2800 square feet of living space on two floors, with a walk-up attic and full basement. Is solar practical in this climate? What is an installation likely to cost and what would be the payback period?

Ed Russo

Your problem is like having a bucket full of holes and wanting to add a second water hose to reduce the loss from the first hose. A home this old would not have been constructed with any insulation in the walls, ceilings, or floor, so the winter heat loss will be much greater than a similar sized home built to today's construction standards.

In addition, a 100-year-old home will probably have loose fitting wood frame single glass windows and lots of un-calked cracks and crevices to let in substantial cold air infiltration.

Before considering any type of solar system I suggest first completing several low cost measures that will substantially reduce this home's heat loss and the fuel needed to heat it. Since you are in a colder climate, I suggest adding a minimum of 12" batt or blown-in insulation in the attic above the heated ceiling below, and 6" batt insulation between the floor joist under the ground floor (basement ceiling).

I would next add storm windows and doors and try to reduce cold air infiltration by caulking all cracks and open joints around door and window frames, foundation base plate, and exterior wall penetrations. You should easily be able to reduce your monthly heating bills by 25% using these simple low cost improvements.

--Jeff Yago


Woodburing stove

We want to install a wood burning stove with viewing windows in our family room as an alternative to having a fireplace built. Is there really much of a difference between different brands or should we shop mostly based on price?

David Mann

Like anything else in this world you usually get what you pay for.

You indicated that you would like a freestanding woodstove having doors that allow viewing the fire. You will find that the lower cost stoves will use glass in the doors that can easily crack due to high temperatures, and clear ceramic material in the doors of higher cost stoves that can withstand very high temperatures without damage. However, all clear materials in the door of any woodstove will eventually become coated with soot and smoke and will require frequent cleaning.

Most double jacketed or airtight freestanding woodstoves now include one or more small electric fans to circulate room air through interior air channels for heating. The lower cost stoves sometimes include inexpensive and very noisy fans that soon fail from the high internal heat. More expensive stoves will use better-insulated and much quieter fans that can last many years.

Regardless of which stove you choose make sure it includes a round duct connection in the bottom or back to allow connection through an outside wall for combustion air. This will reduce using room air that must be replaced by unheated outside air infiltration.

--Jeff Yago


Solar water pump

We live on a small farm and have cattle on several remote fenced areas that we currently must truck water to each day. There is a small pond nearby, but it is located in an area of our farm that we do not want cattle to have access. Since it is too far for us to run an electric line, is it possible to install some type of solar powered water pumping system?

Larry Wilton

This is a fairly common solar application and very easy to do using solar components that you can obtain from the advertisers in this magazine.

I suggest installing two 50 to 75-watt solar modules on a pipe stand located near the edge of your pond and facing in a southern direction. The solar modules should be mounted high enough to avoid damage from your cattle or enclosed by fencing. You will need a solar pump controller that provides several electrical safety features for the pump and maximizes the voltage and current output from the solar modules.

There are several submergible 12-volt and 24-volt pumps available that are designed for low flow high head applications. These pumps can provide a small but continuous flow for most of the day up to a watering troth or holding tank that can be as much as 200 feet above the elevation of the pond. I suggest suspending the pump above the bottom of the pond to avoid picking up mud or debris. The solar pump controller will have additional terminals that can be wired to a remote float switch that will signal when the pump should start and stop.

If this is still confusing, a future issue will include an article on this type of application.

--Jeff Yago



Read More Ask Jeff Yago

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Sorry. Jeff no longer answers questions online

Comments regarding this column may be addressed to editor@backwoodshome.com. Comments may appear online in "Feedback" or in the "Letters" section of Backwoods Home Magazine. Although every email is read, busy schedules generally do not permit a personal response to each one.









 
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