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Get Powered Up! Certified Energy Manager Jeff Yago answers your alternative energy questions

Wondering about a great new energy-saving device
you found on the Internet? Then CLICK HERE!

Sorry. Jeff no longer answers questions online.
This will remain as a searchable
resource for all BHM website visitors.



Archive for the ‘Electricity’ Category

 

Off grid system in Alaska

Thursday, June 18th, 2009

Hi Jeff.

We’re from Alaska and thinking about buying 20 acres where electricity is nowhere to be seen.

And since the sun is scarce in the winter, we’re wondering what kind of a generator-battery-inverter system would be advisable and what’s the approximate cost of setting it all up?

Wind power is not an option either, as the data shows less than 5 mph, year round.

Any advice would be greatly appreciated.

SharLynn

Sharlynn,

You guys are in a tough place.   I have talked with many folks from there and your choices are limited.

The first thing you need to do is really limit your electrical usage.  I assume you will be using a wood, oil, or propane cook stove, space heater, and water heater.   I would not have any heating system that requires operating a central fan or air handing unit as these require lots of power.

I would use only a few low wattage compact fluorescent and mostly LED lights for lighting, and buy only very energy efficient short wave radio, flat screen TV, computer, and video equipment.    You must lower your energy needs first, and it’s worth paying extra for the higher efficiency devices.

Batteries do not like the cold, so they need to be above freezing.  Diesel generators do not start when it drops below freezing unless you use crankcase and carburetor heaters, and you cannot run these high energy loads 24/7 on battery power.  This means you need to find ways to keep the generator area above freezing.

Solar systems can work that far north for the periods of the year when the sun shines, but a generator-battery system will be needed the rest of the year.

I would check with neighbors to see how they deal with this.

Good Luck!

Jeff Yago

 

Power Save 1200 or similar products

Thursday, May 21st, 2009

Jeff,

I came across an add for the Power Save 1200. Electricity flow “cleaner” with a 1K solar panel to connect without batteries. We are on the grid and looking to waste less and minimize our “footprint”. http://www.power-save1200.com/1200.html. They have an assortment of interesting products.

Would like your opinion.

Thank you!

Donna

Donna,

Even if we installed wind and solar equipment for free, no labor charges at all, just the hardware costs for either system would easily exceed many thousands of dollars, so anyone that claims they can do this for $299, tells me there may be more to the story. For example, the web site you referred me to is very interesting as it discusses in detail their solar grid-tie system, but no costs or sizes are given, and a grid-tie wind system, but no costs or sizes are given, then the ad goes into describing this power saving product with a $299 price, as if it included all the solar and wind features that were also listed as if this was all the same product.

Based on the very limited information provided as to how this “black box” can save up to 25% of your home’s utility usage, a figure I highly doubt, it appears to me this is just another capacitor bank with an added whole house surge suppressor. Yes, there are times when large motor or transformer loads on an electrical system can cause the voltage and current to be out of phase more than 90 degrees as required for maximum power conversion. However, I do not know any utility companies that measure this power factor penalty except for large commercial clients since this requires installing a separate power factor meter. It is highly doubtful that even if you had an extreme case of all kinds of motor and transformer loads in your home, odds are this is not being metered or is not enough to cause the type of added savings being claimed by this device. The only time we install equipment like this is for a large retail store with thousands of fluorescent lights, or a large industrial facility with all kinds of large motor loads.

As far as the mentioned benefit for having a surge suppressor, yes this can save your appliances from damage if there is a major voltage surge on the utility line like lightning nearby, but you can buy a whole house surge suppressor at Lowes for about $40.00.

I suggest that you first contact your local utility to see if they even measure power factor on their residential meters, and if they do, ask them what this added utility cost is. If it is not metered by the utility, the only benefit I can see to adding a capacitor bank would be if your power factor was so bad that it was increasing the actual VA metered usage, and for that you would need a whole house-full of motor and ballast loads to realize these kinds of savings.

I say read the small print on anything like this since the basic information being offered before the sale is too limited to actually know what you are buying, how it works, and how they are measuring their very high utility savings. Odds are this sample case is nothing like your home.

Buyer beware,

Jeff Yago

 

Wind Power Question

Monday, April 20th, 2009

Jeff,

I saw a catalog at NorthernTool.com, and there was a ad for a wind generator 120 volts , not DC and the ad stated “Run your meter backward”. The item number in this catalog is Model #44470. It states it also comes with an inverter built in.

Why would you need a inverter for 120 volts?

Second will this piece of equipment really work as it is in this ad?

If it does work as it is in the ad what if anything else will you need to set it up and does it come under the Federal law that the power company is required to let you use it in the system as long as they are advised of the equipment being on line?

Thanks

Bill Wilson

Bill,

I saw an ad for a car that can go 120 miles per hour, but that does not mean I can drive it down the Interstate at that speed if I buy it. In other words, the ad you reference may say you can turn your meter backwards, but you cannot do it legally unless you install all of the required safety dis-connects as required by your local utility, you complete their application form, and then they replace your existing electric meter with a model that records each in and out electric flow separately. Some states have other requirements like providing the utility with a copy of your homeowners liability insurance policy and having a lockable handle exterior disconnect switch for their use.

Although this company is known for their quality wind products, I don’t like having the inverter mounted 75 feet up a pole and subject to all the weather extremes. The inverter is the weak link in most of these systems and I want a system where this is at ground level and have as few electronic components as possible up on a tall tower and in the weather.

Most small wind systems generate DC power for battery charging. What they have done is mounted a DC to AC inverter inside the wind turbine to convert the DC electricity from the turbine into 120/240 VAC which can feed back into the utility grid. However, you cannot legally just plug this into the wall outlet and “turn your meter backwards”.

On another note, for those readers wanting to do something like this, please understand that the power output from any wind turbine is “wild”, in that it jumps constantly all over the place as the wind changes direction and flow rate. You cannot use a standard DC to AC inverter with a wind turbine since the voltage and current goes to such extremes every few seconds. Most inverter manufacturers make a “modified” version of their solar inverters to work with wind turbines, and most are designed for ground mounting in a protected area.

Also note that there are very few areas of the US with enough wind to make these worth the cost and the easiest way to tell is if there are already other wind turbines nearby. Those areas of the US with lots of wind year-round are usually already covered with wind turbines. Although you might be the first in your area, you may want to check a wind resource map for your state first before paying out $6000 plus.

Good Luck,

Jeff Yago

 

Solar powered wireless routers

Tuesday, April 14th, 2009

Hello Jeff,

I’m looking to link some wireless networks via direct links with larger antenna arrays (constructed from home “dish” antennas). A particular link does not have line of sight (small hill in the way). I wish to place a wireless router as an access point on top of that knoll, but will need solar power to operate it. I’m looking at 12V/2A for the router. Of course, I’m attempting to keep size to a minimum on both antenna and solar unit. Any suggestions on required solar gear?

Thanks,

John

John,

I have had several articles describing how to size and install a small solar power system including the article on a solar cabin in the current issue that is on the newsstand in a week or two.

Although it should not take much to power a small unit like you are talking about with solar, I will give you a word of caution. Most DC powered telephone answering machines, and some computer network equipment like routers utilize either a “floating” ground or a reversed positive ground system. You would not normally notice this because this equipment typically uses one of those plug-in AC transformers that convert the 120 VAC from the wall outlet to 5, 9, or 12 volts DC as required by the small electronic devices. However, we have had major problems with “hum” or communication line noise when we tried to power this DC equipment directly from a DC source without the external plug-in power supply, since the ground was either reversed or the equipment had isolation filtering provided by the transformer.

Although your solar power system charging a DC battery might easily have the capacity to power this equipment, you need to verify that the equipment will work when powered directly, or you will be forced to add a 120 VAC inverter to supply the power and that involves added battery losses and much higher cost. It’s best to keep it simple, but some equipment just will not work without the isolation function of the plug in power supply. Check first.

Good Luck,

Jeff Yago

 

Electric heaters

Friday, April 10th, 2009

Jeff,

Thank You very much for your help [with my sump pump question]. I will start looking at other energy users in the house. Maybe I am overlooking something.

I do have an “Eden Pure” electric heater, but it says it won’t use much energy at all. What is your opinion of those?

Thank You,

Arnie

Arnie,

I get this question 10 times a week. All these electric heaters have claims like they will heat your house for pennies a day, or only use the same power as a coffee pot. Here is the dirty little secret of the first law of thermodynamics – They are all the exact same efficiency. There is no difference in how well they can heat anything and I defy any manufacturer to prove me wrong.

Any electric heating coil is considered 100% efficient since all thermal losses of burning fuel occurs at the power plant and during power transmission before the electricity gets to your electric meter, so there are no combustion losses like you would have in a oil, wood, or gas fired heater. All the electrical energy going into any electric heater (not counting a heat pump compression cycle) is turned into heat. The heat content of a kWh of electricity is 3,413 BTU per hour.

This means for every kWh of electricity that goes into the electric heater’s power cord, you will get 3,413 BTU per hour of heating coming out. Of course, if a heater has a fan it might blow this heat out more than a heater without a fan, but it does not matter if the heater has a radar shaped reflector, a fan, or fake fireplace logs, all you get out is what goes in.

Now as for claiming they only use the same electricity as a coffee pot, this may be true. However, your coffee pot only boils water for 5 minutes a day then turns off. Try this: As soon as the coffee pot heats the water to boiling, empty it into a big bucket so the heat can disperse into the room and refill with cold water. Do this all day long and see how much power that takes. This is how long those little heaters would need run to heat a cold house.

Yes, if you stand in front of one of those heaters you will feel warm and they will heat up a room, but a typical home will have a central furnace in the 85,000 BTU/H or higher capacity, and that means it would take a lot of “coffee pots” to provide the same amount of heat required to heat a home.

I have one of these fake fireplaces in a sun room that has great winter window views, but its too cold to sit out there without a little heat, so we use our fake fireplace to heat it a few hours every few days, but I am not expecting it to heat my entire house and believe me, it really spins the electric meter when it runs.

Hope this helps,

Jeff Yago

 

DIY baby-steps Hybrid system design

Wednesday, April 8th, 2009

Jeff,

First of all, thank you for offering a place where the rest of us can ask power questions! We really appreciate what you are doing.

We are looking to both test our location for wind potential and in the meantime fractionally lower our monthly bills – especially our overall peak electricity usage – by way of self generated power and better home efficiency.

After doing some research and checking prices we have come up with what we hope to be good theoretical plan to produce a little energy and perform our test. Unfortunately, we cannot get straight answers on how the proposed system might perform, if at all. We have found similar all solar solutions, but we really like the idea of harnessing the wind – we have a ton of wind, but only so many hours of light.

The proposed Hybrid test components are as follows:

Wind – 200W VAWT (specs below)
Solar – 50W solar panel
NC25A/12volt charge controller
Smart Sine Wave Inverter-250W (sadly, not UL listed but the next version in April 09 will be)
5 x 100 watt bulbs (temporary diverter load)

All plugged into an existing dedicated 20amp GFCI outlet, left over from landscaping.

I wanted to ask specifically is this even worthwhile to attempt to do this project. Will this configuration cause components to die a premature death? Will these components work together? And possibly what other pitfalls, if any?

The only issue I could really easily identify is the inverter start-up voltage was pretty high, which doesn’t take full advantage of any low speed wind energy. Because of this I opted to additionally use a solar panel to jump start the voltage, which may help during daylight hours anyway. But again, this is why we are writing you as it is all a little out of our league.

We know this isn’t much power to produce or save, but I think it will make us more aware of what we are using and it will likely knock us down a tier or two on our power bill while additionally helping up plan for our next steps. That and we feel buying a “wind survey” or wind survey equipment isn’t likely going to supply us with all the practical knowledge we are sure to gain playing around with our own working model!

Thank you,

Charlie and Sara

Charlie and Sara,

If you guys want to “play around” with this proposed system as a learning experience then go for it but remember, a 20 amp circuit could easily kill you under the right grounding conditions. However, I can offer you some warnings if you ignore that advice.

If you check a recent email question from another person wanting to do this same thing, I pointed out that most wind turbines cannot be connected directly to a standard solar inverter because the output power is “wild.” A grid-connected wind turbine requires a special, modified solar inverter designed specifically for a wind turbine, and if you go the way you are going I am willing to bet you will quickly burn up your inverter which is NOT designed for this type application.

You also cannot connect a solar module and a wind turbine together to “jump start” the system as you describe. Each will require their own charge controller type device to prevent reverse charge flow and coil damage.

If you want to know wind potential at a site, you can purchase a recording wind meter for $74.00.

I don’t see how your approach will teach you anything useful except how fast you can fry electrical equipment, as a real wind turbine installation will not have the same performance issues of your experiment.

Also, you have not describing any safety disconnects, fuses or circuit breakers, and have not discussed the fact that it’s against utility regulations to make this connection to the grid without written approval, and this requires evidence that your inverter is both UL listed, and certified for grid backfeed applications.

Again, I am not against experimenting as a learning process, but I am afraid all you will discover with this approach is how fast you can burn up several hundred dollars worth of equipment.

Be very careful,

Jeff Yago

 

AC or DC generator. What’s the difference or which is better?

Thursday, April 2nd, 2009

Jeff,

I’ve been looking at different generators after reading some of your articles. My goal is to build a home that uses generator power while I slowly shift to solar as it becomes financially effective. That being said I’m looking at using a propane generator so I can have a propane stove, and a propane water heater for radiant floor heating. Using this much propane I figured that a propane generator just made sense in order to stick with one fuel source.

Here’s the problem – all the Kohler generators I look at all output AC power and some output it in single or triple phase. I thought it would be better to get a generator that outputs DC to the batteries then use an inverter to output to AC.

With most examples I would have a generator that outputs AC which would have to get converted to DC which would get reconverted to AC when I use it. Isn’t this an awful lot of energy loss?

Isn’t there a propane generator out there that runs at 1800 rpm and will output DC? I mean after all, a propane motor can have different kinds of generators hooked up to it can’t it?

Thank you

Dean Ash

Dean,

Up until around 1995 what you are trying to do was very common as most DC to AC inverters were not as reliable and could only produce a modified wave form output which was not very good to power any type of battery charger. There were several manufacturers making a generator that consisted of a gas or propane engine driving a heavy duty truck DC alternator for direct charging large batteries. There are a few still being made, but since todays higher quality inverters now have perfect grid quality (or better!) sinewave output and very high capacity battery chargers built in that are designed to operate from either grid power or a generator, we now design everything around normal 120 or 120/240 home wiring systems.

Since these new inverters are so efficient, the system losses are almost the same when using a high quality inverter to charge a battery bank with a generator to power the inverter, as it would be to use an engine driven alternator to charge the same battery bank. Also, since your generator would be supplying 120/240 volt AC, you can supply larger AC equipment and power tools directly that you could not do with a DC output generator. Unless you are planning a very small battery system and are trying to avoid the cost of an inverter, I would go for a high quality generator like the Kohler which we prefer since it uses a very simple 2-wire start/stop circuit. This makes it very easy to remote control from almost any inverter, while many other generator brands require complex 3 or 5 wire start circuits which sometimes require buying a separate control box to allow remote start/stop control with an inverter.

Good luck,

Jeff Yago

 

AC generator voltage problem

Tuesday, March 31st, 2009

Jeff,

I have a 7500 Watt AC Generator and have a output voltage problem. If I set speed to 60 cycles my AC voltage climbs to 165 volts. Can you direct me to points of this problem that may help me correct same?

The normal rated output should be 60 cycles and 120 volts AC

Thanks

Bob Libbon

Bob,

There are many possible reasons you are having this problem and each generator brand and model have different designs that could cause this. First, what type voltage meter are you using? If you are using a $20 Radio Shack model, then your meter is giving you a good indication that there is a problem. If you are using a high dollar RMS volt meter, then this may be telling you something else. The actual “peak” voltage of the utility grid and a 120 volt nominal generator is actually 169 volts. This is because the voltage is changing every 1/60 of a second from a high of +169 volts to -169 volts and passing through 0 volts twice, so 120 volts is the “average” of this sinewave curve.

As you start adding loads to a lower cost generator, the internal voltage regulator allows the voltage to drop as it tries to maintain current for the load. This means the peak to peak voltage of 169 volts will start to drop. Since all battery chargers use only the “peak” part of the sinewave, as soon as this peak voltage drops, most battery chargers will stop charging, which is why you should not use a low cost generator to charge a battery bank like you would find in a solar home.

Some generator designs are based on a rotating coil that is supplied a DC current, and by varying this DC current the generator can control the AC voltage output from the fixed coil. Sometimes the voltage regulator device used to vary this voltage includes a control that you can adjust.

Some higher cost generators include a special “inverter” electronic circuit connected to the generator output to stabilize this voltage and maintain the 169 volts peak to peak at a perfect 60 cycles per second. For example, most Honda generators add a “i” to the end of the model number if they include this option.

Odds are your generator has a circuit board that is used to maintain the voltage output and something has gone wrong with this control board. Even lower cost generators have some type of control board to regulate the voltage output even if they are not as accurate as the inverter models.

Sorry, but sounds like this is going to cost,

Jeff Yago

 
 


 
 

 
 
 
 
 
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