Sine wave inverter

Hello Guest,

It's not really practical to "design a Sine-wave Inverter" anymore.

No matter what size or frequency, it has become cheaper to purchase a new one, complete with Maker's Warranty, rather than make one's own.

Kind Regards....

Maybe it's cheaper to buy an off-the-shelf product but that way you will never learn how it works...

Some links:

http://www.qsl.net/dg5sga/inverter.htm

http://www.s4wsbox.com/?q=node/26

http://www.smps.us/power-inverter.html

Yes , It must be cheap in your location .We have to pay heavy duties and other taxes that its value become too high hence it is hardly affordable. Only big companies and organization could only afford to install these UPS. For the larger middle income population ,cheap solution is local made UPS that provide few hours bach up during power break down or load shedding which is so much frequent now a days --Thanks to the soaring oil prices etc.

Nadeem,

Here in the states UPS' and inverters are, relatively speaking dirt cheap although running 2-5 times the cost of modified sine wave.

Nonetheless, you sound like you might be better off with a gasoline or diesel generator.

Here in Atlanta I could easily get a 5KW generator for 5 or six hundred dollars although for heavy ongoing use you might want a better quality unit.

Of course if you are interested in uninterrupted operation you will also need a transfer switch which depending on the load can be fairly pricey. But, once you have the gear, you have it. If I understand things the situation there is not going to get any better and getting stuff from out of country might be impossible.

For your purposes inverter is better than UPS. But then there is the matter of batteries and maintenance. Of course for a generator you can't get away from the need for fuel.

Just some friendly thoughts.

Surf the net and look at what is available.

j.

Hi jack,

Thank you for your suggestions. There is large gap between what is cheap for you and what is cheap for us. Your pennies are our pounds.your one dollar is equal to our 70 rupees and it is going up.

it is hardly cheap for me to get from USA the sine wave inverter and how many quantity I could import. I want to mass produce the inverter locally.

Diesel and gasoline generator is in not my schme of things, though our markets are overflowing with these generators.

It is not a problem for me whether it is inverter or UPS.We could easily convert the inverter in a UPS. we normally use automobile lead acid batteries .these are cheap and easily maintainable at homes.

I thanks for your time and hope that you understand my position.

Nadeem,

The reason I thought you might be better off with a generator is that rupee for rupee you get more kilowatts per rupee with the generator.

Also, and I am sure you don't want to hear this, your country is in danger of sliding into much the same situation service wise as in Iraq. You may be without any power at all.

As an American I know this government well and if they are unhappy with your new government they are liable to depose it. As you may know they have been doing that here in the Western hemisphere for nigh on two hundred years.

I was and am so concerned about that it led me to suggesting to a Pakistani friend of mine working here as a journalist, and who is an American citizen, that if she could, she ought to get her family out.

It was because I saw the very real possibility of your power situation getting worse that I suggested the generators. Actually, if you had to, you could run a gasoline engine, on the gases from destructive distillation of wood chips. You may know that in Europe during the Second World War folks ran automobiles that way.

Your further remarks show that you see a market there for inverters and so your interest is not just personal. Nonetheless, if your markets are overflowing with generators there must be a good reason for it.

What do you do with batteries when you no longer get any power at all with which to charge them. If you are going to manufacture and sell inverters a generator would give you a tertiary business, i.e., charging other folks batteries.

I hope my gloomy outlook does not come to pass.

j.

Hi Jack,

how gloomy is gloomy for us. We are accustom of hearing such a gloomy scenario ,so don't worry.But if USA decided to spraed war zone from iraq ,Afghanistan to Pakistan and x y --, that would be creating a quagmire for itself also.I hope better sense will be prevailed.

Comming back on the technical side,your contention that if there is no electrical power how to charge the battries .yes ,without the lectrical power battries could not be charged. But Generator needs diesel or gasoline to run ,and I am sure that would be exhosted before our electrical power break down occured.So preparing to go back to bronze age,stop worrying about UPS ,generator,electrical power anything---.

This situation is more gloomier than what you depicted.

Nadeem,

The maniacs running this government are so insane that I am not sure that there will even be an election.

Like I said Nadeem as to fuel, using destructive distillation you can run a gasoline fueled engine on wood chips or similar materials that would produce flammable vapors when heated.

At any rate, sitting here knowing your situation in Pakistan and similar other places, and unable to individually do anything to help, does not feel good.

j.

hi!

what voltage are your back up batteries?

Hi,

I want to use the same 12 volt batteries of automobile.

You wrote:-

I would like to design a sine wave inverter.

What you should have written was that you wanted a design to be given to you.......

There are plenty of free schematics around on the web to allow this to be built, provided you can get the parts......try searching around the web.

Thank you for all of your comments.I don't want a disigned circiut diagram from you friends, and who would be generous enough to provide such a information in such a competitive world.I only intent to share my information with you and gets some tips that could make my journey short.

There are enough website that provide in details the working of sine wave inverter though recombining many ideas is more troublesome.

Diesel generator does't serve my purpose as it generate nasty sound, also making sure the availablity of giesel all the time is irritating.

I thanks again for your valuable suggestion and help.

One last point, a really good inverter, whether its a Sine wave or modified sine wave output (the latter is often not good enough for some sensitive electronic equipment), needs to be so designed that when no output is required, it uses as little of the battery power as possible. Also, the circuit, when in use, needs to be very efficient, I have seen quoted for good units above 70% and if my memory serves me correctly, one was quoting 90% efficiency, how true that was I cannot say, maybe someone else can supply better "ballpark" figures for such equipment......

You need to get a design that achieves the highest possible efficiency when in use so as to conserve your battery power, even a change of a few % to the better will make a measurable difference in the time that it runs.....

With regards to batteries, (read up on the web from Battery manufacturers!) I would like to encourage you NOT to use normal car batteries as the "SAFE" amount of electricity that you can use is extremely limited, if you want a long life.

Car batteries are designed to deliver a high "Cranking" amps for a quick start, not longterm discharge as you need.

Generally speaking, over charging and over discharging are both bad for any lead acid battery, but for car batteries, it REALLY does reduce the total life of the battery if you discharge below 12.6 volts or continually charge above about 13.6 volts as then gassing starts, which is both exceedingly dangerous (an explosive mixture of Hydrogen and Oxygen) and will result in water loss and eventual loss of capacity (and eyesight and your face if close to the battery when a spark ignites the gas!!!).

You need what are often called "Leisure" batteries, that can handle being deeply discharged better, but are not so good with the so called "Cranking" amps that I mentioned earlier. They are more expensive, but will eventually be a saving, but try not to deep discharge them too often as in the long run, they do not like this either.....

Please read for deep discharge as meaning less that 12.6 volts. Many will argue this figure, but that is a safe level that means no damage will have occurred....

Have fun.

Here they are called deep discharge batteries.

Here also, because all the online data operations services are being exported to India, the huge backup battery banks, are on the market at ridiculous prices, albeit used, but hardly used. I actually bought six 80 AH deep discharge batteries, that were like new, for eighteen dollars apiece.

But Andy is right. Deep discharging car batteries is disastrous for their health. You may pay more for deep discharge but not when you keep replacing car batteries.

j.

Thank you Andy and jack for your suggestion.

I am looking for the deep discharge batteries.These are little expensive than the automobile battries. when we used the Automobile battries ,we have given the protection in the control circuit that it should not over charged-- controller normally cut -off the charging on 13.6 or any level you decide. Similarly ,when providing the bach up power it is checked regularly that battries should not be discharged less than 12.6 volt or any limit you want to assigned. These auto battries normally worked good for two years.After that you have to replaced with new one.

Getting good deep discharge battries that could run more five years would be better chioice if we get in better price .But again we faced the same problem.Battries are heavy in weight and so the import duties are? We have to rely on our local products.

As suggested it is cheaper to buy the inverter off the shelf.Many inverters having wave forms close to a sine wave are available.

Hello again, Nadeem Usmani,

The best long-term solution would be to install Solar cells, charge batteries from those, and use an Inverter to power what you need.

I do realise that such may be expensive, and subject to thievery, and even here, Solar cell electric generation is still too expensive for me, although I can see the long-term benefits.

Local New Zealand costs for good system is around US$40,000, and payback period is presently around 16 years.

The type of rechargeable batteries I would use are: Nickel-Iron-Hydroxide = Edison Cells

The reason for using those cells, instead of lead-acid, even though at 1.2Volts per cell, more cells would be needed, is longevity, as cells of this type are still working perfectly after some 70+ years.

I would run the battery at 48 Volts.

Kind Regards....

Sparky?

Where the hell do you get Edison cells or batteries. I've read about them, years ago in books, but never actually seen one.

j.

Hi Sparkstation,

yes ,solar panel would be ideal for anybody working on their own power generation.Basically ,I don't need a unit for my home. I want to design something for mass production-- dozens of unit if not in thousand.

Since last two years i was working on solar panel and wind turbine. Both are good to provide the continous charging to your battry bank ,hence supply continous power utility.

Solar panels are expensive- there cost is around 3000 US$ / kwatt( if I am not wrong) . you add 30 - 40 % freight and duties.

Similarly, wind turbine are costing around 1000-1500 $ /kwatt. Add 30- 40 % duties.

Wind turbine are cheaper solution than the solar panels but you are extremely dependent on wind speed. We don,t have enough wind speed required for good generation of power. whereas solar ponals required the sun lights which we have in abundance.Only waiting for technology become little cheaper and affordable.

Hope that become possible in near future.

Nadeem,

Go here

http://www.engadget.com/2007/12/10/researchers-create-printed-solar-cells/

And here

http://www.nanosolar.com/

j.