A few DC pump questions

[BaghdadBean]

Hey guys, returning to hobby after a looong hiatus in midst of a 142 gal custom dream tank build. Obviously equipment and knowledge has expanded quite a bit since 2006, but I don’t need to reinvent the wheel on certain things either. I have a beast of a downdraft skimmer, and I was wondering if they make external DC pumps for those sorts of applications that actually work. When I started my tank build I lived in a urban area, but since then I’ve moved way out to a rural area, and I’m trying to build this baby so that I can withstand week to two week long power outages (Hello fire season). We do have generators, but I’m not always right on hand to go fire up a genny so I’m hoping I can get at least 6 hours off battery if possible. My original idea was to have a small DC pump power one of my OM 4 ways for water flow during outages, but nowadays I see DC has come a long ways. Would it be feasible to run a DC pump for the return on a tank this size? What’s the longevity on these babies? I’m pretty dead set against internal pumps, I’ve had enough issues with them to never ever want to deal with one again, and my tank and sump are both plumbed for all external water moving devices only, hence the dual OM 4-ways vs power heads. Am I chasing unicorns here?

(don’t mind the carpet, we’re pulling the subfloor, reinforcing the structure with some more footers & then installing ceramic tile and a couple oh-crap drains on flex adhesive)

 

[lapin]

I think the problem you will have is: DC pumps are not rated for very much head pressure. So you have to get a bigger pump to push as much water as an AC pump can push up hill.

 

[BaghdadBean]

I think the problem you will have is: DC pumps are not rated for very much head pressure. So you have to get a bigger pump to push as much water as an AC pump can push up hill.

That’s what I was wondering. I kinda figured it would be a chasing unicorns to find a DC pump that could run my skimmer. But re: return pump, would a DC be a viable option at all?

 

[lapin]

It was my understanding you need a pump that you can run off a battery back up. So it will depend on battery size and the pump watts / amp draw.

Yes there are many DC pumps that you can use as a return pump

 

[outhouse]

I think the problem you will have is: DC pumps are not rated for very much head pressure. So you have to get a bigger pump to push as much water as an AC pump can push up hill.

Not really true today. Im old school and used an Iwaki AC pump for 2 decades in my basement. Now the last 5 ish years ive been using a jebao dcp 10000 which does a better job and I have it turned down to 45 watts which has paid for the pump in a years time in electricity savings. reliability has been top notch. To give you an idea my DC pump can push water at 18 feet.

 

[outhouse]

return pump, would a DC be a viable option at all?

Yes. Reason is the electricity savings and controllability the AC pumps do not have. Almost all DC pumps can control flow, as to where the best AC pumps cannot. Also do what I did for northern Ca fire conditions and power shut offs, get a small generator, have never suffered a single loss.

 

[outhouse]

Am I chasing unicorns here?

Yes, generator the best way to go.

Would it be feasible to run a DC pump for the return on a tank this size? What’s the longevity on these babies?

Im running a 120 dollar DC pump in my basement to my 210G display in living room. Longevity? keep your impeller clean and the AC savings pays for the pump in a year. I have a back up impeller and pump for just in case, and I froze an impeller by not cleaning for a year, which was my fault. my back up is 5 to 6 years old. Oh and amazon had the impeller for 29 bucks. So now I clean and soak in CLR every 6 months. I see no problems getting a decade or longer out of the cheap disposable pumps

 

[BaghdadBean]

Not really true today. Im old school and used an Iwaki AC pump for 2 decades in my basement. Now the last 5 ish years ive been using a jebao dcp 10000 which does a better job and I have it turned down to 45 watts which has paid for the pump in a years time in electricity savings. reliability has been top notch. To give you an idea my DC pump can push water at 18 feet.

I’m gonna respond to all your posts here in this one. I‘m not contesting gennies are best. I’m looking for a 6 hour bandaid so somebody can get home to fire up the generator that we already have. We live in a remote area, my spouse works 2 hours away from home, and I’m often on the road doing livestock deliveries, so there’s a bit of a gap on generator kicking on vs power going out.

So… if you’re saying that’s a unicorn, but at same time you’re saying DC pumps are totally viable, I’m a little confused as to overall messaging here. Out of curiosity, how old is your Jebao pump? I’ve read a lot of mixed ratings on them.

Thank you for the input, I do appreciate everybody’s different points of view and the valuable experience you’re sharing.

 

[jda]

A well oxygenated tank can go many hours without a pump - 4 hours has been no problem for me. You also probably aren't going to be out doing deliveries when Tornados, Ice Storm or Blizzards are forecast so this cuts down on a lot of it. If this is a huge issue, then put a standby generator with auto transfer switch on your list - good for lots of things in suspect areas.

DC pump won't save you any power if you use a good AC pump. AC pumps are more reliable and can handle head better. You can turn the flow up and down with DC. I don't have a tank upstairs but an expensive Abyzz used 2 more watts than my Laguna Max Flow did to deliver the same water up stairs. For a return pump, either works, but I would have a spare DC pump on hand.

For the skimmer, you can get a huge DC pump to drive it. They most suck at head pressure, so you have to just throw GPH at it. You won't likely save any wattage. Most folks don't understand a downdraft, so be careful whom you listen to.

For longevity, some claim that DC pumps will last a decade, but none of them have been out long enough to know, so it is all conjecture. Most have received updates and fixes to known problems, so the clock has reset. The bottom line is that none of them look like an Eheim or Askoll Block pump yet of which you certianly don't have to have perfect maintenance to have them last. They might, but who knows...

 

[BaghdadBean]

A well oxygenated tank can go many hours without a pump - 4 hours has been no problem for me. You also probably aren't going to be out doing deliveries when Tornados, Ice Storm or Blizzards are forecast so this cuts down on a lot of it. If this is a huge issue, then put a standby generator with auto transfer switch on your list - good for lots of things in suspect areas.

Thank you for the thoughtful response. My tank is 6’ x 2’ x 19“ so it’s got a pretty good surface area for the size. Our ranch is wired for a manual switch gennie (you gotta do the block off switch on the breakers to run it on gennie), and we have a couple big Hondas for the basics, and the baby Honda for the wells. We thought about putting a monster diesel gennie here but… eh… for the amount of days we typically go blackout on I’m not sure it’s worth it outside of the convenience of keeping everything on exempt diesel (We have an onsite 500 gal diesel fueling system for our heavy equipment/tractors/etc).

Re: downdraft skimmer, I hear that loud and clear.

 

[jda]

If you ever get one, one of the ones with the Ford V6 or Inline 4 that run on LP and/or natural gas are the best, IMO. We had one in Missouri that had a Ford 3.0 v6 in it, which is easier in cold weather than a diesel, super reliable and you could use a BBQ tank if you got in a pinch. Nothing worse than your diesel not wanting to start in the cold and/or you having to go out there with a can of spray. They are not cheap, but a good idea if you are going to stick around for a long time at the home. The v6 could do like 20kw, or something like that, so plenty of power... you don't need hundreds like some of the big diesels generate. We only really ever needed ours for the aftermath of ice storm and/or tornados which you kinda know are coming - ice storm for a week and tornado possibility for a day or two. I don't recall ever being out and about and needing to rush home to take care of anything just out of nowhere... we lost power for a few minutes or half of an hour, but it would come back on outside of these instances. We lived in the country too and a tornado many miles away could affect us for a week or more. Ice storm once was almost 3 weeks, but we had almost 1000 gallons of propane and it ran almost nonstop perfectly.

 

[outhouse]

there’s a bit of a gap on generator kicking on vs power going out.

Gotcha, that info would have been nice up front.

Circulation your best friend, I would not use a dc pump for that. I would use the battery back up for a pair of MP40's.

So… if you’re saying that’s a unicorn,

Nope you misunderstood me

how old is your Jebao pump?

over 5 years old. As many name brands I have heard of failing, these are right in line with 90% of the pumps out there, but cheaper costing. most dc pumps are either chinese or rebranded chinese.

 

[ksed]

A well oxygenated tank can go many hours without a pump - 4 hours has been no problem for me. You also probably aren't going to be out doing deliveries when Tornados, Ice Storm or Blizzards are forecast so this cuts down on a lot of it. If this is a huge issue, then put a standby generator with auto transfer switch on your list - good for lots of things in suspect areas.

DC pump won't save you any power if you use a good AC pump. AC pumps are more reliable and can handle head better. You can turn the flow up and down with DC. I don't have a tank upstairs but an expensive Abyzz used 2 more watts than my Laguna Max Flow did to deliver the same water up stairs. For a return pump, either works, but I would have a spare DC pump on hand.

For the skimmer, you can get a huge DC pump to drive it. They most suck at head pressure, so you have to just throw GPH at it. You won't likely save any wattage. Most folks don't understand a downdraft, so be careful whom you listen to.

For longevity, some claim that DC pumps will last a decade, but none of them have been out long enough to know, so it is all conjecture. Most have received updates and fixes to known problems, so the clock has reset. The bottom line is that none of them look like an Eheim or Askoll Block pump yet of which you certianly don't have to have perfect maintenance to have them last. They might, but who knows...

Which Abyzz and Laguna?
Abyzz typically will do very good at high head and Laguna was not really known for high head.

 

[ksed]

Cricket’s

 

[BaghdadBean]

Which Abyzz and Laguna?
Abyzz typically will do very good at high head and Laguna was not really known for high head.

Probably moot point for me, since I’m not dropping that much money on a single pump when I’m already camping on a number of them. From my POV I could afford a third generator at the same cost as one Abyzz. Thank’s for the input though!