amps vs watts cost?

[Anonymous]

I am doing a comparison between running 400 watt 20 k xm SE bulbs on HQI ballasts and m59 ballasts.

So far the HQI pulls 5.13 amps at 450 watts and the m59 pulls 4.2 amps at 475 watts.

Which costs more to run?

 

[Anonymous]

watts=volts*amps

The price of your elec is kW/hour. Do the math. More watts=more amps= more money.

B

 

[Anonymous]

Where did you measure those readings?

 

[Anonymous]

Thanks.

I am getting less watts at more amps which is confusing me.

 

[Anonymous]

Hey Mike,

I took those reading with a Kill A Watt p3 plug in meter.

 

[Anonymous]

Thales wrote:

I am getting less watts at more amps which is confusing me

That just means that the power factor, or efficeincy, of one ballast is better than the other.

Like Bingo said, volts times current = watts. This is the real wattage regardless of what is marked on the lamp.

If you measure the volts and the amps, then this formula gives you an absolute answer.

The wattage ratings of lamps is approximate.

Louey

 

[bleedingthought]

So, which one of his bulb is using up more energy?!?

 

[Anonymous]

So, the ballast producing the lower wattage in the bulb is cheaper to run?

 

[Anonymous]

I'm not sure how the kill-a-watt meter works with power factor issues, if I had to guess I'd say that the one with higher amps is actually more costly, simply because measuring the current is fairly straight forward. maybe the meter is trying to compensate for a power factor, perhaps over compensating.

 

[pwj1286]

personally since you are using high amperage ballasts (and most aquariums suck up alot of amps, with chillers and all) you should be more concerned of your amperage usage when it comes to your circuit breakers. You dont want a constant trip like mine does. I think I use a total of 20+ amps easy. I have to keep alot of my eletrical stuff on seperate circuits. Make sure you have atleast 20 amp breakers and 12 guage wire to run your lights.
_________________
Cooking Chef

 

[Anonymous]

Hmm. Thanks Mike.

No worries about tripping breakers. My system is currently using 4 dedicated circuits.

 

[Anonymous]

So, the ballast producing the lower wattage in the bulb is cheaper to run?

The one that draws less watts is cheaper to run. You electric bill is based on watts consumed. Are you measuring the watts at the bulb or at the power cord?

 

[Anonymous]

Watts are what costs money, but you're not likely measuring watts. You're measuring current and voltage. Use the formula to figure watts. Then whichever one is the least is the cheapest to operate.

Having said that, since your voltage is constant, current is the only other part of the equation. So the one that draws the less amps will be less watts and therefore less costly.

10-4?

Louey

 

[Anonymous]

What type of ballast is the "HQI" one? Does it have solid state electronics? I'm sorry but HQI is thrown around so often I don't know. There might be some back EMF occuring from the transformer coils in those guys which are tossing off the readings.

 

[Anonymous]

I am not very confident about these gadgets.

You should only look at the wattage number. Now, I think killawatt has a voltage function, and you will notice that it give different number even if you plug it into the same socket.

The issue with AC is that it is not constant voltage. If you have a bunch of people in your house, how would you say is the height of your household? The mean, the median, or the RMS, or the average height?

 

[Anonymous]

k k

 

[Anonymous]

Hey guys,

Here is some more info from the meter. I just did the tests again.

• HQI PFO ballast
  amps 5.13
  volts 117
  watts 457
  va (?) 602
  hz 59.9
  Pf (?) .75

• m59 ballast
  amps 4.26
  volts 117
  watts 481
  va (?) 499
  hz 59.9
  Pf (?) .96

I don't know what va is, but I am pretty sure pf is power factor.

Any of those numbers shed any light on anything?

Thanks!

 

[Anonymous]

VA is volt-amps. It should equal the volts times the amps.

The pf if the power factor or effieciency of the ballast.

As you can see, the M59 is a high power factor ballast. That is why you're getting more watts with less current.

The actual forumula for watts when pf is known is W = amps X volts X PF (%).

Louey

 

[Anonymous]

So the HQI uses less watts and will be cheaper to run, but the m95 is more efficient?

Thanks guys...I am questioning through this thread without doing much google so we can mark the thread for archiving.

 

[Anonymous]

I think the VA is V_rms*A_rms, and the V you see on the gadget is acutally V_rms and A_rms, and that's why V*A=W != VA due to this rms statistic.