electrical question

[reefsRcool]

starting the setup of my new tank(75)this weekend and finally will be getting some halides (going with a pair of 150 watt HQI DE giesemanns pendents). my question is how do watts equate into amps? i have to think those lights draw a bit of juice and i have a pretty rugged sized return pump(don't ask what cuz i don't know got it used with the tank) plus all the other assorted junk to run too. and am starting to doubt the daisy chain of powerstrips i had under my 55 will be up to the needs of the new setup but all they state is the amp rating. anyone know how to figure that stuff?


while you're all here anyone want to talk me out of the giesemanns before i go and drop two weeks pay on them?

 

[Marcosreef]

ReefsRcool,

Volts x Amps = Watts (120 volts x 20 amps = 2400 watts)

or

Watts divide by Volts = Amps (2400 watts / 120 volts = 20 Amps)

As long as you have two of the three (Volts, Watts or Amps) you can use the ohms law circle to figure out the missing parameter.

So your 300 watts of HQI would equate to roughly 2.5 amps at 120 volts.

Also you should not go over 80% of the circuit capacity, for example a 15 amp circuit can deliver 1800 watts, but you should not load it for more than 1440 watts max.

Regards, Marco

 

[DJ88]

reefs,

Marco,

In DC Ciruitry you can use the VoltsxAmps=Watts.

IN AC you can't. They don't equate to be the same.

By doing that math you end up with what is called Volt Amps(VA). It isn't the same as a Watt.

The best way to find out how many amps you are drawing is to find out the ratings fom the manufacturer. Unless you are able to hook up and measure the current yourself with an ammeter capable of handling the current within that device. If you aren't familiar with how to do this or don't have an clamp on ammeter I don't recommend doing it.

hth

 

[Anonymous]

Yep, just read the lables, then add up the amps. You also have to remember that everything 'pulls' more amperage on startup. That is why your 300w HQi will be labled as 3 or 4 amps, not the number you come up with in the math that marcosreef did. However, The math will give you a good idea if you only have watts listed on the lable. Just remeber to add a little extra for a safety factor.

HTH

Brett