PUMP ELECTRICITY CONSUMPTION

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aeri

Candiru
MFK Member
Sep 11, 2007
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Toronto
anybody have any information regarding watt consumption vs GPH on pumps/powerheads out there?

i've noticed my bill rising and it's because i cheaped out on some of my equipment and only looked at price vs gph rather than watts. for example a maxijet 900 outputs 230GPH at 8.5watts, whereas a maxijet 1200 outputs 295GPH at 20watts.

i found a bit of info from this website: http://www.wetwebmedia.com/ca/volume_3/cav3i1/Powerhead_test/powerhead_comp.htm

i'd like to find out a bit more about other pumps like quiet one, lifetech, etc. but can't find any.
 
IMO and from what I have read on other boards you have to take the manufactures stated power consumption with a grain of salt. I found it to be often under rated by about half. Generally it seems the better brands are a more accurate. Measuring the actual consumption is a little disheartening. A few examples I had was mag 5 claimed 45, actual 98w, 2 Laguna 2905s claimed 130 actual 230w, Jebo claimed 70w uses 190w, Harbor freight claimed 100w used 290w. My canisters were pretty accurate.
 
Here is my take. The harder the pump has to work, the more energy it will use correct? For an external pump, the initial wattage rating is probably at zero head. So if you have a pump that flows 2000 GPH at zero head, it may consume 140watts, increase the head to 4 feet and say the pump only puts out about 1200 GPM and the wattage increases to 210watts?

Those numbers I picked out of a hate but I am going to guess that is why the actual power consumption is higher than what is given by the manufacturer. Let me know if I am wrong but this is how I see it.
 
The examples I have seen seem to contradict this at least on some pumps. Specifically that they have higher power consumption when working harder. For example the Reeflo website states that by throttling down their pumps you can lower the wattage draw. Throttling down just means putting a partially closed valve on the output end, which is making the pump work harder.
 
Too answer the OP question I go to 'drsfosterandsmith' find a pump and then click the more information link. They usually have consumption and head tables there.
 
The examples I have seen seem to contradict this at least on some pumps. Specifically that they have higher power consumption when working harder. For example the Reeflo website states that by throttling down their pumps you can lower the wattage draw. Throttling down just means putting a partially closed valve on the output end, which is making the pump work harder.
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Exactly, I wasn't thinking of a valve to control flow. I was thinking of an open piping system without valves and only head to effect the flow. Any form of restriction will cause the pump to work harder.

I suppose I should have worded my post different.
 
The pump is doing the most work at zero head therefore the most wattage. At higher heads it's moving less water therefore consumes less power. Throttling back is the same as increasing head.

Any form of restriction will cause the pump to work harder.
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Just the opposite is true. Restriction (higher head) = less work = less power consumption.

Everything is proven in this thread.

http://www.monsterfishkeepers.com/forums/showthread.php?t=70671
 
Everything is proven in this thread.
Click to expand...

I like that statement!! I'll check it out. I wasn't sure if I was right or wrong, hence the "I could be wrong" statment in my first post.
 
Just read the thread. VERY informative. Thanks!

That thread brings back some memories, and those were playing with pumps, restricting the flow, only to hear the pump rotor spin faster with zero flow and slower with flow. Interesting.
 
Just the opposite is true. Restriction (higher head) = less work = less power consumption.

Everything is proven in this thread.

http://www.monsterfishkeepers.com/fo...ad.php?t=70671
Click to expand...

That is true for external pumps. Power consumption will drop when throttled back.

I have found it does not work near as well for submersible pumps though.

I went through some testing last year when deciding submersible vs external for my pond. Throttling back submersible pumps did very little but lower the flow. This is what I found last year: A mag 5 dropped about 5w when I stopped about 50% the water output, (still used about 93 w) and dropped 12w with the output completely blocked. With a 290w sump pump it also dropped 5w drop at half flow and 10w fully blocked. A little 15w powerhead was still 15w at 50% and 14w blocked.

You can get a basic plug in watt meter for under $30 and they are pretty useful for testing items all over your house to find out the actual draw (like 12,000w of Christmas lights)

http://www.discountpv.com/meters/p4400.htm
p3.jpg
 
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