[Exar Jun]

I know a whole bunch of folders out there are asked this question by parents, wives, fellow folders, and even yourself. So I popped out the Ampprobe, took some average readings, did a little research and here is what I came up with.

A typical computer, 300w supply @ .75 running amps and 17" moni. @ 1 running amp, takes about 1.75 amps to run after initial startup. These amp readings were taking directly from one of my pcs that is just folding!

Volts * Amps = Watts. So 1.75A x 120V = 210 watts.

Now to convert this to kilowatt hours...
Say we want your pc to run 24/7...
Take watts x 24 to get the watt hours. this = 5040 and divide by 1000 and you have got 5.04 kwh.

Then take the kwh per day and times this by the number of days in a month (30.4 average days per month). 30.4 * 5.04 = 153.22 kwh per month.

An average charge per kwh is $.065.

.065 * 153.22 = $9.96

This is your "average" monthly charge if you were to leave your rig and moni on 24/7.

This price drops down to $4.98, I won't go though the #s again, if you average only 3 hours a day with your monitor on.

Okay..well alot of us have our monitor on more to watch yatta back-to-back-to-back......but this is for the average family.

I hope this helps people out when you are thinking about folding 24/7 and wonder how much it costs.

I don't know but maybe this information can be added to the F@H forum sticky? I think it would be helpful there for those "future" questions.

Fold!

[NASsoccer]

Originally posted by Exar Jun

I don't know but maybe this information can be added to the F@H forum sticky? I think it would be helpful there for those "future" questions.

Fold!

yes it would be! can you please email me this in a txt file with lots a detail and i will see that J gets it and then puts it up in the FAQ thread??



FOLD ON
NAS

[Exar Jun]

No Prob. I will get it to you later today.

[NASsoccer]

Originally posted by Exar Jun
No Prob. I will get it to you later today.

thanks a lot and superb job on getting all the info together, it is much appreciated


FOLD ON
NAS

[Gator]

Originally posted by Exar Jun
...

Volts * Amps = Watts. So 1.75A x 120V = 210 watts.
...

Uh... Nyet, nope, not quite true. Volts x Amps =/= watts... Try again guy. Hint: Your talking A/C here...

[Kakao]

Uh... Nyet, nope, not quite true. Volts x Amps =/= watts... Try again guy. Hint: Your talking A/C here...

Yes volts x amps = watts

I had the same thought but was enlightened by Edward2 in this thread:

http://forum.oc-forums.com/vb/showth...threadid=83905

Edward2:
Kakao, you are correct about A/C voltage and current being sinusoidal. However, 240 VAC does not alternate between +240 and -240V. It actually alternates between +340 and -340V.

120VAC and 240VAC are actually something called the "Root Mean Square" (RMS) value of the sinusoidal voltage. This RMS value is sort of the average voltage, ignoring the fact that the voltage is sometimes negative. All normal multimeters measure this RMS voltage value. 240VAC(RMS) = 340 / (square root of 2)

Therefore, the power consumed by the fan is roughly equal to the voltage times the current. P = V * I

There is another whole topic regarding the phase angle between the voltage and the current sinusoids which also effects the the power calculation, but I will not go into that right now. For the purposes of calculating the power consumption of the fan, you can ignore this.

[Matthew1001]

I don't keep my monitor on all of the time I fold. When I am not at the computer I turn the monitor off. What percentage is the monitor?

[Gator]

Originally posted by Kakao


Yes volts x amps = watts

I had the same thought but was enlightened by Edward2 in this thread:

http://forum.oc-forums.com/vb/showth...threadid=83905

Sorry guys, but you are both STILL WRONG. Voltage and Current are indeed sinusoidal waveforms... but here's the key: They are NOT NECESSARILY IN PHASE with each other.

VOLTS x AMPERES = VA (Apparent Power)

WATTS is a measure of TRUE Power, which is related to VA by the POWER-FACTOR of the load. A pure resistive load, like a lightbulb, has a power-factor of 1, but motors and electronics rarely do. The typical home computer has a POWER-FACTOR of around 0.70 or therabouts.

VOLTS x AMPERES x POWER-FACTOR = WATTS, i.e. the base note overstated the watts by quite a bit, it would not be 210 watts, but closer to 150.

-The Gator

[Exar Jun]

Uh... Nyet, nope, not quite true. Volts x Amps =/= watts... Try again guy. Hint: Your talking A/C here...

Sorry...your information is incorrect Gator.

Ever hear of P = IE where P is Power, I is Ioda or Current, and E is Electromotive Force?

Definitions.
Power is the rate at which work is done, in this case we are talking about electrical push which is measured in watts.
Ioda is the movement of electrons through a conductor. This is measured in amps.
Force is the relation between energy and charge which results in electric pressure, this is also called voltage.

This is one of the most basic electical formulas next to ohm's law, which is E = IR where R is resistence or ohm's

Through basic factoring, you can find any of the four if you have two of the values.
P = IE | I = P/E | E = P/I AND E = IR | I = E/R | R = E/I

I know I was talking about Alternating Current. Last time I checked, the electicity company doesn't set a large battery in your back yard and charge you per kwh of usage. I made sure I was telling everyone the correct information when I originally posted this information, this is called research.

I am not into spamming misinformed threads for my fellow teammates. I hope this information make it a little clearer to everyone.

FOLD

[Exar Jun]

Matthew - A monitor consumes a little under 60% of the power in this example.

[Gator]

Originally posted by Exar Jun


Sorry...your information is incorrect Gator.

Ever hear of P = IE where P is Power, I is Ioda or Current, and E is Electromotive Force?

Definitions.
Power is the rate at which work is done, in this case we are talking about electrical push which is measured in watts.
Ioda is the movement of electrons through a conductor. This is measured in amps.
Force is the relation between energy and charge which results in electric pressure, this is also called voltage.

This is one of the most basic electical formulas next to ohm's law, which is E = IR where R is resistence or ohm's

Through basic factoring, you can find any of the four if you have two of the values.
P = IE | I = P/E | E = P/I AND E = IR | I = E/R | R = E/I

I know I was talking about Alternating Current. Last time I checked, the electicity company doesn't set a large battery in your back yard and charge you per kwh of usage. I made sure I was telling everyone the correct information when I originally posted this information, this is called research.

I am not into spamming misinformed threads for my fellow teammates. I hope this information make it a little clearer to everyone.

FOLD

Yes, I know the formulas you state above... and they work well ... FOR DC RESISTIVE LOADS... but when you play with A/C and motors, you no longer have pure resistive loads. Read up on "Power Factor"...

[Exar Jun]

Now I see what you are getting at. You posted a second time will I was writing my post. I had forgot to include PF. I never really use it unless I am testing three phase motors. I know that you need to find what are your true input watts and then divide that by your supposed watts or V*A. .7 seems low for a PC though. Where did you get that info Gator?

[Kakao]

Originally posted by Gator


The typical home computer has a POWER-FACTOR of around 0.70 or therabouts.

VOLTS x AMPERES x POWER-FACTOR = WATTS, i.e. the base note overstated the watts by quite a bit, it would not be 210 watts, but closer to 150.

-The Gator [/B]

This is what I think about and it is only what I think:

The power factor is real but it happens inside the PSU then the PSU can only supply 150W to the components but would draw 210W from the wall.

Then if Exar Jun measured amps between the wall and the PSU the P=IxV is correct

[Gator]

Originally posted by Exar Jun
Now I see what you are getting at. You posted a second time will I was writing my post. I had forgot to include PF. I never really use it unless I am testing three phase motors. I know that you need to find what are your true input watts and then divide that by your supposed watts or V*A. .7 seems low for a PC though. Where did you get that info Gator?

Mostly by measurement on some really sh*tty old PC's, so I may have been a bit pessimistic with the 0.70 figure...

Older PC's, (and maybe some newer "your getting a DUUD, d00d" PC's too), will typically fall in the low .70's.

However one CAN get better "power-factor-corrected" (PFC) power-supplies which are closer to unity PF. (I think PC Power&Cooling's PFC supplies claim a 0.90 power-factor? Those are great PSU's but EXPENSIVE AS HELL!)

Motors, (fans, drives etc), and big-ass electromagnets like in your favorite monitor tend to drag down the overall power-factor a lot.

For example: my LAN here is all powered from a 2KVA Best Ferrups UPS, which has built-in monitoring out the wazoo, voltage, current, VA, and true watts, and the aggregate numbers for these 7 machines, misc network boxes, etc are: Voltage=120vac, Current=11.6A, 1397VA, Power-factor=~0.75, and 1054watts. PF seems to vary from as low as 0.72 up to 0.77 depending on what I turn on or off. None of these machines have PF corrected supplies though.

-the Gator

[JetMech]

Actually both methods of computation are correct in their own right. P=I/E gives a ballpark figure which is great for training, etc. Gators formula is real world and includes variables that will result in a more accurate figure. For what we do an approximation works just fine. Exar Juns information would give a worst case figure and will compensate for such things as fluctuations in current flow. When we factor in cooling fans, water pumps, different processors, overclocked vid cards, and different speed hard drives I think it is plain to see that nailing the exact consumption of a system or farm is virtually impossible. For this reason I prefer to use Exar Juns high side computation and add 30%.

[FoldingAddict]

So, Exar’s calculations are more or less correct? So $5 a month without the monitor is about right?

[JetMech]

I would use it. As a matter of fact I,d use 6.50 to be on the safe side.

[Gator]

Originally posted by JetMech
Actually both methods of computation are correct in their own right. P=I/E gives a ballpark figure which is great for training, etc. Gators formula is real world and includes variables that will result in a more accurate figure. For what we do an approximation works just fine. Exar Juns information would give a worst case figure and will compensate for such things as fluctuations in current flow. When we factor in cooling fans, water pumps, different processors, overclocked vid cards, and different speed hard drives I think it is plain to see that nailing the exact consumption of a system or farm is virtually impossible. For this reason I prefer to use Exar Juns high side computation and add 30%.

THAT is why vendors selling UPS systems quote their product's capabilities in terms of VA (Apparent Power)... rather than watts (true power.) With the exception of lightbulbs, most hardware you can buy today has CURRENT ratings specified, but not power, so its easier to add up the VA ratings than to come up with total watts requirements.

I.e. my UPS is rated as 2KVA, ( which is about 1400 watts in real use.) However, when I purchased this UPS, I planned ahead, and allowed for excess capacity. When you are puchasing power equipment, it is best to know the significance of any equipment ratings - for your own safety.

- The Gator

And P.S. The easiest way to save bucks on your power bill is to TURN OFF your monitor whenever you aren't going to be watching it! The system can continue to fold happily along without the monitor turning power into heat.

[Exar Jun]

I think that it might be best to post the high end because the power factor would not be consistent on everybodies rig that may read it. Some pcs will use the wattage better than others and it is best to argue worst case scenario.

I hear ya Gator. In exacting how much power you are "truely" using, use must consider power factor.

I think something else to consider, if you are going the exacting route, is to take into account how clean your current is. Some UPS "direct" the waves into a consistent(why does that look spelled wrong) pattern and this may increase your power factor.

Ah...electricity, the unseen entity. Very complex!

one more addition: Yeah I use the power settings in xp to shut off the monitor after 15 min of none use. I don't use any screen saver(that doesn't matter anyway)oh well.
Bottoms up on another cold one.

[Mr B]

I've got a much easier calculation where I'm at;

PC's + 120VAC = $$

Wife + Hi120VAC bill =

So, when Wife = , my 120VAC bill is too high.

Therefore, Wife - $$ + PC's/Hi120VAC bill = Julia Roberts/Richard Gere movie.