DC Controllable Pumps vs AC Pumps

gcarroll · Mar 7, 2017

d2mini said:
3/4 is the largest.
I didn't notice much difference in flow when I installed it. If it made a big difference I would have had to make a good adjustment to my drain valve.

this one looks to be 1".
https://www.aquariumcomputer.com/usa/product/flow-sensor-9000-lh/

jason2459 · Mar 7, 2017

d2mini said:
3/4 is the largest.
I didn't notice much difference in flow when I installed it. If it made a big difference I would have had to make a good adjustment to my drain valve.

Interesting. I'm not to familiar with the Vectra but does it have some sort of automatic flow regulation or something? Where if it senses some back pressure it automatically increases power to some extent?

I'd be curious if you put on a killowatt with out the flow meter and see how many watts it pulls and again after putting on the flow meter. With out some kind of "smart sensing" thing going on the watts pulled should go down slightly along with the flow with the flow meter in place. If it is sensing the head pressure and increasing flow I'd expect to see a possible increase in watts used or stay the same. Which is possible how it senses flow increase and decrease by monitoring the watts pulled. If watts pulled decreases then increase power... etc.

gcarroll · Mar 7, 2017

jason2459 said:
Interesting. I'm not to familiar with the Vectra but does it have some sort of automatic flow regulation or something? Where if it senses some back pressure it automatically increases power to some extent?

I'd be curious if you put on a killowatt with out the flow meter and see how many watts it pulls and again after putting on the flow meter. With out some kind of "smart sensing" thing going on the watts pulled should go down slightly along with the flow with the flow meter in place. If it is sensing the head pressure and increasing flow I'd expect to see a possible increase in watts used or stay the same. Which is possible how it senses flow increase and decrease by monitoring the watts pulled. If watts pulled decreases then increase power... etc.

I'd be curious to this as well. I have the feeling that you will find that DC is not so energy efficient as we have been conditioned to believe. I am not 100% sure but I would bet the following.

DC pumps do not decrease in wattage like AC pumps when head pressure increases
AC pumps can actually be more efficient under head pressure applications.

DBR_Reef · Mar 7, 2017

jason2459 said:
Thanks Dennis. I'll be interested to see what the flow rate is after the swap out. I'm guessing the barbs are a big factor and will help the most to get rid of.

Does GHL have a 1" or bigger meter? The 3/4" meter will reduce the flow a noticeable amount. Its like putting on a valve and closing it a quarter of the way.

You should be able to connect any generic flow sensor, but you might have to do your own programming- I have no experience with the ghl though.

jason2459 · Mar 7, 2017

DBR_Reef said:
You should be able to connect any generic flow sensor, but you might have to do your own programming- I have no experience with the ghl though.

You'll also want to make sure of no brass or other metal components. For my return I've always just filled up a bucket and got my flow rate that way. But it's cumbersome to setup and a one shot deal.

d2mini · Mar 7, 2017

gcarroll said:
this one looks to be 1".
https://www.aquariumcomputer.com/usa/product/flow-sensor-9000-lh/

That's the one I have. It's just under 1 inch I.D.
The coupling (like that on each end of a ball valve) that converts it so we can use standard USA pvc fittings is 3/4".
I forgot about that though... maybe thats why I didn't see much of a diff because it only has to squeeze through the coupling.

revhtree · Mar 7, 2017

I was talking with @Terence about flow issues as well and he said it's a big mistake to go with smaller return lines like 1" or even 1 1/2". I believe he suggested at least 2". I am also having flow issues and plan to redo my return lines.

d2mini · Mar 7, 2017

revhtree said:
I was talking with @Terence about flow issues as well and he said it's a big mistake to go with smaller return lines like 1" or even 1 1/2". I believe he suggested at least 2". I am also having flow issues and plan to redo my return lines.

Ya its true, aways go big.
But in my case my run of pipe is so short, and once I hit the return I'm forced to use the Elos internal plumbing which is small, so not much point in me going big.
Makes much more sense for your build or my old build. I had 1.5" for every thing there and could have used larger.
The problem though is costs go up quite a bit! Have you seen the cost of a 2" Cepex ball valve... or even gate valve?

revhtree · Mar 7, 2017

d2mini said:
Ya its true, aways go big.
But in my case my run of pipe is so short, and once I hit the return I'm forced to use the Elos internal plumbing which is small, so not much point in me going big.
Makes much more sense for your build or my old build. I had 1.5" for every thing there and could have used larger.
The problem though is costs go up quite a bit! Have you seen the cost of a 2" Cepex ball valve... or even gate valve?

Ah I see...and no I don't want to look.

ksed · Mar 7, 2017

According to my testing with a DC pump at 0 head pressure it was using 55 watts and with about 8 ft head pressure the pump was still using 55 watts. It does not appear that added head pressure decreases the wattage of the pump unlike the AC counterpart.

Cliff717 · Mar 7, 2017

Have you considered maybe it's the pump? I am using a l1 now and it's performance is so poor that my old gen-x pcx40 outperformed it. Mine is going back to ecotech for warranty as soon as I get my baccacuda rebuilt and back on the tank in place of the l1

jason2459 · Mar 7, 2017

ksed said:
According to my testing with a DC pump at 0 head pressure it was using 55 watts and with about 8 ft head pressure the pump was still using 55 watts. It does not appear that added head pressure decreases the wattage of the pump unlike the AC counterpart.

I have shown high head pressure can reduce wattage even on a DC pump here
https://www.reef2reef.com/threads/mtc-mvx-skimmer-review.252436/

And the other question I would have is knowing what the wattage is being pulled by the pump from the controller vs controller from the wall outlet.

Like my waveline dc 12000 is rated about 20 watts more at the outlet then at the pump.

d2mini · Mar 7, 2017

Ok, i replaced one 1" 45 degree elbow and two 3/4" barbs and silicone tubing with 1" flex pvc that connects to a 1" to 3/4" adaptor at the overflow.

With this, I gained maybe 35 gph. lol

But I still have the restriction between the pump and the ball valve to deal with.
That should free up a good amount.

ksed · Mar 7, 2017

jason2459 said:
I have shown high head pressure can reduce wattage even on a DC pump here
https://www.reef2reef.com/threads/mtc-mvx-skimmer-review.252436/

And the other question I would have is knowing what the wattage is being pulled by the pump from the controller vs controller from the wall outlet.

Like my waveline dc 12000 is rated about 20 watts more at the outlet then at the pump.

All of my measurements were taken from the wall.

Docpayne82 · Mar 7, 2017

Can I ask where you were able to find flex pvc? I've tried all the big box hardware store with no luck and my LFS had no idea either. I found it online but the shipping is more than the pvc!

jason2459 · Mar 7, 2017

ksed said:
All of my measurements were taken from the wall.

Mine too which is why I'm very curious what it's actually pulling at the pump. I'm not sure a clamp meter will work for DC and I'd have to rig up wiring for it with out ripping apart the actual wiring to find out.

Edit: yes it does look like it will read dc as well... curiosity will kill this cat one day

Docpayne82 said:
Can I ask where you were able to find flex pvc? I've tried all the big box hardware store with no luck and my LFS had no idea either. I found it online but the shipping is more than the pvc!

What size? I got some from Doctor Foster and Smith for a good price and free shipping with ordering some saltmix too.

http://m.drsfostersmith.com/product/prod_display.cfm?pcatid=29798

TylerS · Mar 7, 2017

The single largest affect to head pressure (besides vertical distance) is velocity through the pipes. Velocity is squared in the head loss equations, and area is related to the diameter squared. This is why using too small of connectors or return lines can have a huge impact to your flow loss.

I'd pull out all the stops and upsize to 1.5" from the pump all the way to the water in the tank.

You could even split the return line into two 3/4 lines and it would be larger area than a single 1", but a single 1.5 inch or two 1" would be better.

TylerS · Mar 7, 2017

Even if you get a more powerful pump you'll just end up paying for the flow loss in electrical costs.

bhavy · Mar 7, 2017

Hi
I have 2 L1's for returns in my 200 gal . Sump is in basement directly below. They run 100% and I can tell you I'm getting at least 12-15x turnover! I used 1-1/2 pvc on the outputs that split with spa wye fittings to connect to 1" flexible pvc. So each end of tank has 2 - 1"
Bulkheads as outputs.
Love the flow! I can send pics if you like. My point is the L1's have plenty of flow. It's really about volume not psi. It's a law of hydraulics thing. You have to many restrictions and bends and such.
Use flexible pvc where u can!

d2mini · Mar 7, 2017

Docpayne82 said:
Can I ask where you were able to find flex pvc? I've tried all the big box hardware store with no luck and my LFS had no idea either. I found it online but the shipping is more than the pvc!

My local Home Depot. $4.22 per foot. Expensive but I only needed 5', compared to the 25' minimum online.