Cheapest backup power for house? Discuss.

[mcstar]

Paul hit on my point exactly. Nothing in the described device supplies any power to keep the system going, overcome frictional losses, over come electrical losses etc. I suppose you have to have actually built a few things before you realize what's possible and what's pie in the sky. Rod, I encourage you to go ahead and build it if you're so set on it. But it will be far cheaper to learn what others have already figured out regarding how energy actually works. Old college physics books can be found at Amazon for $10 or less. Some colleges even offer their courses online for free (mit open courseware comes to mind)

 

[paultrafalgar]

Here's the application of Capstone Microturbine Technology to a coach:
http://gas2.org/2008/10/17/ecosaver-iv-altairnano-microturbines-and-mass-transit/#more-1136
Now what interests me is mating one of those 30Kwatt turbines to a fast-charging battery like the Toshiba SCiB and using that combination as an off-grid power supply. This assumes that the penalty for stopping and starting the turbine was not too great. My house uses about 5Kwatt hours per day. So I could run the turbine for one-hour every 6 days! I think that would be VERY EFFICIENT!
What do you think?
Edit: Sorry, this should be in:
Most expensive backup power for house!

 

[dogman dan]

Now all we need is the 5000 watt version.

 

[Mathurin]

Generator RPM could be maintained by a mechanical governor.

A system that is added like old-school aftermarket air-conditioning might be better than wheel-driven PTO. Since gen-heads are kinda large, perhaps a hydraulic pump could drive it in a convenient location and also manage the RPM regulation.

That reminds me, one of my buddies back at la poc lived out in the woods without electricity, to weld stuff he had a lawnmower with two big alternators each connected to a lead acid slab.

So, add an alternator you can weld with to a car that runs, connect an inverter and let the car idle when you need it? Seems it would be fairly cheap if you don't need it too often.

 

[dogman dan]

All the welders from Juarez Mexico have trucks with an extra alternator, and just idle the truck while they weld. You want to see real Mcguyvering go to mexico, after the drug war ends of course.

 

[dogman dan]

Browsing the northern tool catalog today, I thought " lets see what you could get for under $5000 in the photovoltaic stuff". Big mistake even opening the catalog of course, but just for grins, I did some fantasy shopping. Turns out you could get a setup that would give you about 1500 watts of backup power for 20 hours, or for another $500 or so, 40 hours and so on. Three 123 watt panels, giving, in my climate, 2 killowatt hours a day, charge controller, a big battery and a pure sine wave inverter. If you used the system daily, you would save abourt 8 bucks a month off the electric bill in my town, less in most other places.

Oh well, so much for that fantasy, using such a setup to power some luxury things around the house, like TV, ebike, etc. Even if the tax credits got the cost down to $3,500. it would still take 35 years to break even. Good thing a larger system could be bought at much better prices than Northern Tool.

Truly, there are so many better ways to shave 8 bucks off the electric bill, but if off grid in the boonies, It could be enough power to get by on if not using a refrigerator.

 

[vanilla ice]

N.tool has some affordable gen heads too if you want to do gasoline or water or wind or whatever.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=98800

I was thinking this might be a good start for turning a moped/scooter/motorcycle into a portable (rideable) generator setup. Well, at least easier than starting from scratch.

 

[dogman dan]

There is some cool stuff in there for sure. Wish I had some falling water on my property! All we have here is solar and tons of it. But I need a bigger tax credit to make it break even in less than 30 years. Meanwhile my homemade solar hot air collectors are kicking ass. The ones in Northern tool are pricey, but much nicer than my homemade ones. I need the solar powered fans on mine to increase thier efficiency. Two panels, 3'x 6' are saving me about $50 a month in electricty to heat the house. In my climate, that is cutting the heat bill in half. To most of you though, my heat bill is a joke. When we first bought the house, it was no joke to us though. The place was poorly insulated, all electric, and when I tried the fireplace it was so inefficient that it make the house colder. That first year heat cost $250 a month compared to $100 in the old trailer. Now, with improvements to the fireplace, insulation, and now solar heat, it's down to about $50 a month, including a big rate increase.

 

[paultrafalgar]

ywanna post some pics of your homemade solar collectors for the folks to copy, Dogman?

 

[dogman dan]

I've been meaning to start a thread on em, but hadn't yet since I wanted to see how they performed on keeping the house warm when it got actually cold. It just did that this week, and while not even close to as nice as before, they seem to be pretty worth it. I was sure the performance would be a lot less once the glass had actual cold air on the other side. The condensed version is, they seem to be working, yesterday it dawned at 25 F and the high was only about 45, which here, could be one of the coldest days of the year. I did run the heater in the morning to get the house to 65 F since we had just had two days without sun, and after the days heating, the house was at 70. This morning, it's 27 F out there, and the house stayed at 65 all night. That will do, I just want to not have to run the heater all night, and not wake up to 50 in the house. It's hard to quantify how much heat I really get out of this setup, but in similar conditions last year, the house would never have got above 65 in the day. Since I live in a warm sunny climate, the heat I'm gaining is a pretty big percentage of what I need.

 

[Malcolm]

Wish I had some falling water on my property!

I'll trade you as much falling water as you want for a little more solar

I'd like to see some photos of your homemade collectors too, in fact any energy-saving or generating gear that makes us more independent. I got interested in this stuff about 20 years ago when I was living in Sweden, and I did a lot of reading and planning at the time. When I came back to the UK and started talking about solar heating panels and Trombe walls and windmills I just got blank looks from everyone. Now it seems they're cool ... well sort of warm really

 

[pwbset]

I'll trade you as much falling water as you want for a little more solar

Yeah, ditto. By the time I need heat/sun for the house in November it's cloudy/snowy for 7 months straight and dark at 5pm. *sigh* Now if only I could figure out long term storage for the 4 straight months of pure sun we get from 12-14hrs a day from July-Oct. If I had the money I'd go with big hydrogen tanks and fuel cells and do this:

http://www.siei.org/mainpage.html

 

[Mr. Mik]

I would agree with TD, for strictly backup use, a small generator would be your best bet. If you do go that route, make sure you use it regularly (at least once a month) so it will work when you need it. I work in the generator industry and non-use is one of the biggest problem causes.

Is it important to let the generator actually produce electricity when running it?

Or is this just needed to keep the ICE happy?

I have a 6.5kW generator and I kick it over every now and then, but I do not turn off the mains power first. I just run the generator for a few minutes without a load. Would that be sufficient to keep it in shape?

 

[dogman dan]

My newer gennie will run fine with no load, but the old honda, 800 watt, will surge and idle and surge and idle, untill it stops after the surge. It seems to need about 100 watts of load to run smoothly. One thing that helps with a gennie that sits is gas stabilizer, that helps cut down on the varnish in the carburator caused by the residue left from evaporated gas. I don't personally do this, maybe why the honda runs shitty, but I do make sure to run the old gas out at least every six months. Running them till they stop and have no fuel in the carb is another way to do it, and keep gas in cans.

We do enjoy the sun here, and we should be producing a lot of electricity and algae fuel. But sometimes I wonder if it is worth it when you have a year with under 6 inches of rain. One year the wind blew from the pacific ocean a lot, and we got totally disgusted with the tall weeds and bugs everywhere when we got 20 inches of rain that summer. Places that get rain regular have other plants that grow and predator insects and animals to keep the bugs down some. Here, if we do get rain, all we get is ragweed 10 feet tall and mosquitos that carry west nile virus and encephalitis. Normal for us is about 9 inches of rain, but at least 6 inches of it will happen in three 1/2 hour storms that sill flood out somebody.

The only easy way to store solar energy I know is to put up a bunch of PV and grid tie it, so you can run the meter backwards in the summer and forwards in the winter. Not exactly storing it, but at least removing some fossil fuel use. Only for the rich, or at least those with more room in the budget for big loans at todays prices.

 

[Mr. Mik]

My petrol generator runs evenly without any load, but at around 1/2 load it oscillates badly sometimes. Just a matter of turning some heavy user on or off, like the oven, then it will even out.

To prevent the build-up of varnish in the carburettor: Would it be just as effective to close the fuel valve (mine has one, like on a motor-bike) until the motor stops? But I am not sure if complete evaporation of a small remaining fuel amount in the carburettor does not actually cause MORE varnish build-up than the evaporation of a little bit of fuel out of a larger amount. Is it not a function of the concentration of longer chained carbohydrates in the remaining fuel concentrate that determines build-up of varnish?

Anyway, it is probably fine if the generator is being run once a month or so.

Is it best to keep the fuel tank full or empty? I like mine at least half-full, because the power usually goes out in miserable weather and the generator is in a tight spot, no overhead space to easily fill it. I use a little hand operated fuel pump to fill it and usually smell of petrol for a day afterwards! It's not what I want to do during a thunderstorm...

 

[MarxNutz]

When power goes out where I live, people start running around trying to figure out why the generator won't start? We all forget that we have gasoline powered cars and trucks. They full of gas and they start. I got big 1800 watt inverter. Hook it to my truck battery with 00 gauge wire. Truck will idle for very long time on a tank of gas. Waste of gas? Yes but it works.

I do the same on a much smaller scale... I have a cheap 350 watt inverter that plugs into the cig lighter of my truck, and it's enough to run a 'legacy' TV and the satellite receiver or DVD player. At least we can get the weather update or watch a movie while the power is out. Or I can plug the laptop in and use the internet (we have DSL, so even if the phone is out, the net still works) for whatever entertainment or informational purpose. This would only do during the warmer months, but we usually don't have any problems in winter. Usually... (c;

 

[dogman dan]

Yeah, closing the valve would do the same thing, the point is not to have gas evaporating, leaving residue, and then more coming in and doing the same thing, for years. Gas stabiliser helps with this too, apparently the gas gets more varnishy as it ages? I really don't know the chemistry, just that it works. I use the generators twice a year for something or other, so I just run the tank dry to remove the old gas, before refilling it with fresh.

 

[vanilla ice]

I turn off the fuel valve and let it run till it dies on our gen. Motorcycles too. Stabil and hi octane. I figure it can evap off a few octane and still be similar to the 87 stuff.

 

[dogman dan]

To clarify my statement, I run the tank dry when I use the generator for something. We use em every fouth of july for a night parade with christmas lights on the floats. Plus whatever power outages we get. Gas up to a year old still works, but it might get hard to start. Gas more old than that is pretty hard to run unless you at least dilute it some. Six months seems to be about as old as gas can get without noticing a difference in how things run. But whatever works to keep it from evaporating in the float bowl of the carburator, or the little bellows pumps if they have that helps keep em running better.

 

[MitchJi]

Hi,

http://www.autobloggreen.com/2008/12/25/prius-generates-power-in-massachusetts-snowstorm/

Prius generates power in Massachusetts snowstorm

As anyone who watches the evening news would already know, the East Coast States have been hit hard with horrible winter weather over the last week or so. This snowy pounding has revealed a new use for the Toyota Prius, or likely any hybrid that recharges its batteries with its internal combustion engine. John Sweeney, a resident of Harvard, Massachusetts, lost power to his home for three whole days. That all sounds horrible, especially in such awful weather. Fortunately, Sweeney came up with a novel way to use his hybrid car by connecting a power inverter to his Prius' battery and using the hybrid as a generator. According to reports, Mr. Sweeney was able to run "his refrigerator, freezer, TV, woodstove fan and several lights through his Prius, for three days, on roughly five gallons of gas." We imagine that proponents for a future electrical grid that gets power from hybrid and electric cars during peak hours are quietly smiling to themselves.

 

[dogman dan]

That is pretty good efficiency compared to just a generator. My 3500 watt one would go through five gallons in a lot less time, like less than a day. Looks like a battery backup charged by a generator would be the way to go like the prius has, so the gennie doesn't have to run all day. Of course a few hours a day will keep the freezer and fridge ok in froze weather, but you might want to keep a furnace running most of a 24 hour day. That prius power source might work real good for something like a weekend cabin in the backwoods, asuming the car can do the road to it. Not ultra green power like solar, but if 5 gallons lasts three days, it's a lot greener than a gennie with no pollution controlls at all on it.

Maybe the ideal set up would be a smallish PV charging a largish battery, and a tiny generator for backup to the solar panels. The idea would be to save on the panels by using a panel size that takes about 3-5 days to charge the battery, and make the battery big enough to last at least 48 hours of running the furnace blower and a few lights like the tv. Not the cheapest, but cheaper than a prius and you could use some of the power in the backup daily, like more or less the output of the panel once the battery is charged without compromising the backup supply. You could wire up one circuit in the house to the backup and use that plug off grid for whatever, daily, getting some of your investment back eventually.

 

[TylerDurden]

Question for the e-e types:

A typical gas-fired hot water furnace/boiler has a 110VAC-24VAC transformer to power the controls...
During a power outage, can a typical computer UPS run the 110V side of the transformer safely? IIRC, they output approximated sine.
(There are no blower motors, simply hot water circulation via convection.)

An isolation transformer seems redundant...

TIA

 

[MitchJi]

Hi,

That is pretty good efficiency compared to just a generator. My 3500 watt one would go through five gallons in a lot less time, like less than a day. Looks like a battery backup charged by a generator would be the way to go like the prius has, so the gennie doesn't have to run all day. Of course a few hours a day will keep the freezer and fridge ok in froze weather, but you might want to keep a furnace running most of a 24 hour day. That prius power source might work real good for something like a weekend cabin in the backwoods, assuming the car can do the road to it. Not ultra green power like solar, but if 5 gallons lasts three days, it's a lot greener than a gennie with no pollution controls at all on it.

So in a year or two the cheapest option might be (if you are purchasing a new car anyway) a PHEV Volt or Prius. With the proposed large tax credit the battery portion might be close to free

 

[Mr. Mik]

I have a question generators and how to avoid voltage fluctuations.

Each time my water pump turns on the lights dim and the generator revs up, fixing the voltage sag in less than 1 second. But the pump turns on and off a lot and this is probably not good for the electronic devices connected to the generator or the generator itself.

Is there a simple way of reducing the inrush current to an electric pump motor?

It's AC, 240V 50Hz.

Thanks!

 

[paultrafalgar]

I have a question generators and how to avoid voltage fluctuations.

Each time my water pump turns on the lights dim and the generator revs up, fixing the voltage sag in less than 1 second. But the pump turns on and off a lot and this is probably not good for the electronic devices connected to the generator or the generator itself.

Is there a simple way of reducing the inrush current to an electric pump motor?

It's AC, 240V 50Hz.

Thanks!

I'm not an EE but this sounds like a job for an ultracapacitor.