The dc pump advantage??

Battlecorals · Jun 9, 2015

something I've been wondering about of a while now. Other than maybe little less noise, I can't come up with any real advantage to having a dc pump on a skimmer.

I get that you can dial it down and all but I don't see why you'd need to.

Help me understand what a dc pump does better for a skimmer? What am I missing?

zesty · Jun 9, 2015

I'm also looking for a non-bs response like I'm about to give.

I'm wondering if you can forgo the height requirement some with the adjustment of the DC motor?

Other than that, I'm out of ideas. I just upgraded to a vertex with a sicce pump; me happy

redfishbluefish · Jun 9, 2015

Produces less heat.
Consumes less electricity.

StikHedRon · Jun 9, 2015

Yeah, I'm going with a DC skimmer for mainly the efficiency of the pump vs an AC version of equal size.

jolt · Jun 9, 2015

I thought I read somewhere that a DC pump will handle frequent starts/stops better than an AC pump. Can anyone confirm that?

redfishbluefish · Jun 9, 2015

Well they do have a slow start, which I would guess is easier on the pump.

ronnie · Jun 9, 2015

Silence. For me, that was key. So the DC pump was key.

IMO, different speeds can also help the skimmer operate more efficiently in different depths of water. I don't have any criteria to back this up other than me messing with the pump and tube adjustment.

pickupman66 · Jun 9, 2015

redfishbluefish said:
Produces less heat.
Consumes less electricity.

this would be it for me. I have a DC return pump and love the dial in abilty for it. it is also silent, low heat and low operating costs. I dont see the need to mess with a pumps speed on a skimmer unless it is just oversized to the skimmer. I have an SCA-302 now and the needlewheel pump it came with has been great, although it is a standard AC pump

gcarroll · Jun 9, 2015

redfishbluefish said:
Produces less heat.
Consumes less electricity.

Really, how much less heat and how much less electricity? AC versions of needlewheel pumps hardly draw much electricity. My WM/Skimz 251 pulls 36 watts between the 2 pumps. while pulling 2600-2800 lph of air. Besides, 36 watts is not much heat.

The Skimz 253 with DC pump:
VSC10000-DC Pump Features:

Six RPM presets
Feed mode with shut off timer
Air Draw: 317-634 GPH (1200-2400 LPH)
Power Consumption: 25-69 Watts

Where is the savings?

Battlecorals · Jun 9, 2015

gcarroll said:
Really, how much less heat and how much less electricity? AC versions of needlewheel pumps hardly draw much electricity. My WM/Skimz 2501 pulls 36 watts between the 2 pumps. while pulling 2800 lph of air. 36 watts is not much heat.

That's pretty much what I was coming up with as well. For needles for sure. Not much of a trade off if any at all.

gcarroll · Jun 9, 2015

Yes and in that instance, the DC pump draws even more energy (nearly double) to produce similar results. I would be interested in the German made DC pumps as they are infinitely adjustable for fine tuning.

ksed · Jun 9, 2015

Pump efficiency lies in the magnetic strength between the rotor and stator for the most part. The stronger the field the more efficient. This can be accomplished in different ways , most notably the type of magnets used eg neodymium and ferric, and the space between the rotor and stator. When using a power supply to step down the voltage you have a power loss . It may be very little but its there. So, AC/DC not much difference in efficiency if both pumps are of similar quality.
Most German pumps like the Abyzz and BK Speedy are high voltage synchronous motors that operate on sinewave waveform all the qualities that make an AC pump. As of now the only German low voltage pump is the Abyzz 100w, anything higher eg 200w and above is high voltage for various reasons.
Dc provides variable speeds , depending on what you are using it for it may make sense. eg Flow pumps.
FWIW Jebao sells the same low voltage DC pump we see here, in Asia, as both low voltage DC and high voltage AC.

JMO

Paul B · Jun 9, 2015

It would not be less heat or less electricity for the same size motor. But it would be safer as it runs on low voltage (which doesn't equal low heat or electricity)
(Master Electrician 40 years, retired)

gcarroll · Jun 9, 2015

But how much safer? Like how a unloaded gun is not as safe as an unloaded gun in a safe? Or is it like an unloaded gun in a safe is not as safe as an empty safe?

Paul B · Jun 10, 2015

No, safe because it operates on low voltage, probably 12 volts as opposed to 110 volts so if the power cord tore, you don't get electrocuted. But that is the only advantage I could see besides being variated speed.

miyags · Jun 10, 2015

Would the DC type pumps have,Battery back-up capabilities?

Paul B · Jun 10, 2015

No, unless you cut the wire from the power supply and connected it directly to the battery. That large thing you plug into the wall is a power supply which lowers the line voltage to about 12 volts (depending on the model) then changes it into DC.
As is, it will not run on DC from a battery.

miyags · Jun 10, 2015

How about with the use of a APC Back UPS

gcarroll · Jun 10, 2015

Paul B said:
No, safe because it operates on low voltage, probably 12 volts as opposed to 110 volts so if the power cord tore, you don't get electrocuted. But that is the only advantage I could see besides being variated speed.

What I'm trying to establish is if the safety measure has merit. How many people get injured from their pump being an AC pump? Just trying to measure the size of that "if".

diablomaster9045 · Jun 10, 2015

I believe it is all about fine tuning. With pretty much all dc pump skimmers they have 3 points of adjustment. Air flow, water in flow, and output opening size. So theoretically, they provide the ability to finetune your skimmer more. But for the price difference, I personally don't think its worth it because the DC pumps are still in their infancy and with a skimmer you want reliability.

I have been intrigued by the Coral Box 500 DC skimmer, but I have been happy with my Bubble Magus skimmers so have not bought one yet.