# DC to DC conventer

Discussion in 'General Electronics Discussion' started by Orzel83, Oct 16, 2014.

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1. ### Orzel83

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Oct 16, 2014
Which converter will be the best option to dissipating at least 2000W from the output of an alternator which is attached to a small petrol engine (typically 12 to 18 V).
Thanks

2. ### KrisBlueNZSadly passed away in 2015

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Nov 28, 2011
You want to dissipate 2 kW of power? You mean, waste it - turn it into heat?

3. ### Orzel83

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Oct 16, 2014
yes, it will be like a load

4. ### KrisBlueNZSadly passed away in 2015

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Nov 28, 2011
So you want a load that will dissipate 2000W or more at 12~18V DC?

I guess you'll need some big resistors, or perhaps a number of heater elements or jug elements in parallel.

To dissipate 2000W at 15V you need a current flow of:

I = P / V
= 2000 / 15
= 133A.

That's a hell of a lot of current. You will need some extremely thick wires. Are you sure you know what you want?

If that's right, you'll need a load resistance of:
R = V2 / P
= 152 / 2000
= 0.1125Ω

That's a very low resistance. You could probably achieve it by connecting a large number of jug elements, from 110VAC jugs or kettles, in parallel.

I think you may have some numbers wrong. Perhaps you should start by telling us exactly what you want to do, and why.

5. ### Orzel83

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Oct 16, 2014
My project is to build an electrical load which is capable of dissipating at least 2000W from the output of an alternator which is attached to a small petrol engine (typically 12 to 18 V). This load should allow the user to set the amount of power that is to be dissipated into the load.
For my load I have available 1ohm Power resistor.

6. ### KrisBlueNZSadly passed away in 2015

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Nov 28, 2011
What is the purpose of the load? Is it designed to test the motor's output power?

So the alternator generates 12~18V DC?

And you have 1Ω resistors? What is their power rating? How many of them do you have?

Did you follow my calculations? Do you realise that to dissipate 2000W at 15V requires a current of 133 amps? Do you know how thick 133A-rated wire is?

7. ### BobK

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Jan 5, 2010
Here is a bright idea: Lots of automotive light bulbs. 80 25W ones would do. And you could rent it out to road crews doing construction at night.

Bob

KrisBlueNZ likes this.

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Dec 18, 2013
Or aircraft landing lights

9. ### KrisBlueNZSadly passed away in 2015

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Nov 28, 2011
He would have to leave a bit of current available to run the cooling fans!

10. ### Orzel83

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Oct 16, 2014
I have just one of that resistor with power rating up to 2.5kW (it's very huge resistor). I wold like to keep the voltage at safety range up to 50V. I was thinking to build a dc to dc boost converter with a full bridge circuitry.

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Sep 5, 2009