Pump claimed power usage

[mrunlucky07]

Since I recently put in a pond I became concerned with the power usage of running multiple pumps in my tanks and the pond. In the past I just went with the claimed stats by the manufactures. I was pricing a new pond pump and wattage is a large concern. Depending on style one pump will pull 1000w and another do the same output for 200w. I have two 2900gph laguna pumps because they are supposed to be very efficient, only 130w. I was thinking of getting a third laguna but decided to test them and bought a watt meter yesterday. I was a bit miffed to find that one used 228w and another 232. 100w more than the manufactures claim. So the Laguna 4200 I was getting is off the list and I am going to bite the bullet for an external.

I tested my mag 5, supposed to 45w, uses 98w.

Jeabo 70w used 190w, more than double manufacturers claim.

My canister filters were pretty close to specs.

The worst is a harbor freight 1000gph pump that is rated at 100w and is pulling 282w. The Lagunas were off, but still 3x the flow for less electric.

Looks like the price does reflect quality a bit, but all were off.

Anyone else test their pumps and find the same thing? Or that they were right on?

 

[gourami]

Well... Thats wierd I dont have a pond soo.... I wouldnt know

 

[jlnguyen74]

I don't, but it could due to the age of the pump, it takes more power to run an old one, due to the impeller doesn't spin as freely as the new one

 

[rallysman]

Maybe they rate the pumps at their max head rating.

 

[DB junkie]

How expensive was the watt meter? Have you tested it on other various appliances to see if it might possibly be the meter? I might be wrong but I think I'de be trusting my fluke and clamp over a watt meter. I know that was the only way to get cost effective realiable measurements out of car amps.

 

[mrunlucky07]

Yeah, they can use more as they get older, but none are very old. From my understanding generally the higher head/less flow the less wattage should be consumed. The watt meter is basic amp/watt meter from Lowes, $30. Nothing fancy or overly precise. I tested it on a couple compact fluorescent bulbs and was right on, to a little bit low. I doubt the meter is off by 180w on a 100w pump and right on with a 100w light. I picked it up after reading about large power discrepancies from several manufactures on other boards. I wanted to test my Laguna pumps because I was planning on getting another one. Their power use claims seemed too good to be true, and I think that is the case. The two laguna pumps I have are about a month old and have only pumped clean water, and are running at 5' of head including plumbing losses. The mag 5 was used about 6 months and shelved, the jebo is about 2 years old and the harbor freight pump is 6 months old.

Its just a little frustrating when manufacturer stats are what we go by and they get exaggerated. I wouldn't worry too much about a 10 or 15% difference, but when a pump clams 100w and pulls 280w, thats significant to me.

 

[rallysman]

do you have a way to block the output? If you have a valve or something close it off and try to check it again.

 

[DB junkie]

I've heard that putting a little back pressure on them actually reduces watts. I'de love to see this myth put to the test. VERY informative post. And I agree 100% that if it reads right on lights then test results should be legit. I'm gonna do some checking on the shibby at my place this weekend. Wheels are a turnin!!!

 

[mrunlucky07]

I've heard that putting a little back pressure on them actually reduces watts. I'de love to see this myth put to the test.

I just did a quick test and I am going to say for submersible pumps it is a myth. I only tested the mag 5 and harbor freight sump pump because they were easily accessible. The mag 5 dropped about 5w when I stopped about half the water output, and dropped 12w with the output completly blocked. I got almost identical results with the HF pump (5w half flow, 10w blocked) It is a sump/"waterfall" style pump. I didn't test the Lagunas.

I have read that with external pumps people have been able to throttle them back with a little success, but generally for significant wattage drops the flow needs to be greatly reduced and is not worth it. I plan on getting one soon and will post an update.