UPS for sump pump

[David Nebenzahl]

Have a client who's looking for some kind of battery-backed sump pump solution.

Not knowing a lot about this equipment, I did a little research. Starting at a business that was suggested by the client (Sump Pump Direct,

I found the following.

There are two types of units available. One is a battery-backed power supply, essentially a UPS, though they're not called that in this application. These are used to power existing ordinary AC operated sump pumps.

The other thing available are sump pump back-up "systems". These are pumps that are designed to operate from household AC *or* 12 volt DC battery power. When power fails, they switch to DC and run from a sealed lead-acid battery. The whole thing is sold as a unit and replaces an existing sump pump.

My customer already has a sump pump installed (two, actually). She also has frequent power outages during the times when the pump is needed. These outages can last as much as 4-6 hours.

I've looked at some of these "back-up system" pumps. They don't give me a whole lot of confidence that they'll be there on the job when needed. And while one of them claims a "battery life" of 7.5 hours, I'm not sure that means it'll actually run that long on battery power.

I'd like to at least research the other (UPS) alternative. One unit on the Sump Pump Direct site is this one:

for long link)

It looks great; uses two deep cycle 120-amp marine batteries. Only problem: these systems "start at" $1,800 (not incl. batteries). No thanks.

I then discovered that it's very difficult to sort through all the UPSs available out there in web-land. I stopped looking after most of my searches returned results from bizrate.com, nextag.com, and other scum-of-the-earth, shake-you-down with tons of ads while you're sucked through their vortex of web sites.

I did look at some UPSs at this site:

They have a ton. But when you actually find one that looks like it might work for you, they have virtually no technical details available (like one crucial one in my case, how long it'll provide battery power).

So I'm hoping someone here might have experience with these units. I know that most UPSs are made for computers, network gear, etc. But if there is one that can provide enough power for the sump pump motor (including any starting inrush current) for long enough, it should work. I'm not absolutely sure of the motor ratings at this point, but I would reasonably assume a maximum of 1/2 HP (induction motor), so probably 7-8 amps operating current max. I will, of course, nail this down before seriously recommending a UPS, if it comes to that.

Of course, it needs to be reasonably inexpensive. $3-400, maybe: $1200, I don't think so.

Any help here much appreciated.

[Paul Franklin]

Forget about a UPS solution for $400. Using your figures, you need say 8 amps @ 120 volts for 6 hours. To get that from 12 volt batteries, assuming 90% conversion efficiency (very unlikely in cheap equipment) you will be drawing about 89 amps from the batteries. For

6 hours, that means you need 534 amp hours of capacity. To get that capacity with reasonable battery life (meaning you can still get that capacity as the batteries get older) you'd need to start with a minimum of 6 120 amp hour deep cycle batteries.

You're already well over your price targe, and you don't have any electronics. Even if you assume 50% duty cycle for the pump you're not going to do it for $400.

I have two of the Basement Watchdog 12 volt systems. They will run for a few hours continuous when the battery is new. Depending how much lift you have and how much water you need to move.. one of those may do the job; but in my experience you are really pushing it. They work well for relatively short 1-2 hour outages and modest lift and flow applications.

If there is city water, a water powered backup pump is a perfecty reasonable solution here, and will be close to your price target.

The solution you really want is an automatic backup generator, nat gas or Propane fueled. Figure $5k minimum, but you get the advantage of having some power for other things as well.

HTH,

Paul F.

[jamesgangnc]

As another poster pointed out if you want significant runtime you'll need a whole bunch of batteries. We have large scale ups in our computer rooms. Part of maintaining them is the regularly scheduled pallets of replacement batteries.

A generator is a far better solution and can be extended to operate other things in the house. Main problem is do you need an automatic start and transfer generator or is the customer around during these power outages to start a generator and throw some transfer switches? That's usually the big price break.

[jamesgangnc]

glegroups.com...

You can make that pretty straight forward and electric start generators can still be had for a reasonable price. But they tend to be a bit bigger. The smaller 1-2 kw ones are all pull start. My main point being that the biggest price break is when you go from that sort of setup to the completely automated setup. The ones that start the generator and transfer the load when the power fails without you doing anything.

[IGot2P]

Just point your browser to

and take a look. I have had one of these systems for approximately seven (7) years and it has saved my tush several times. This system will kick in if the power goes out or if your current sump pump simply quits working for some reason such as the switch goes bad, etc. I did replace the battery after six (6) just to be on the safe side.

Don

[Robert Green]

I have a very similar system (seems exactly the same except the pump is yellow). It's mounted in the sump on a cinder block so that if the main sump fails for any reason, when the water level rises just over the cinderblock the emergency sump kicks in. If you're in the middle of a 1000 year flood, you can recharge the battery with your car and some jumper cables, I suppose.

It's never been an issue for me because I have a number of wheelchair batteries around that aren't quite dead but don't hold the charge they used to. They'll still power the pump for a few hours run time if the main battery gets depleted. So far I've never had to use them. Someone previously talked about why these systems don't give a "run time" for their batteries; I assume that's because each situation is different. If you're in the middle of that 1000 year flood the pump might have to run continously. Otherwise, it could run every 2, 5, 10, 50 minutes, etc.

Systems that run 120VAC pumps really don't lend themselves to battery operation without a lot of conversion losses from 12VDC batteries to 120VAC current. That's why I got a 12VDC powered emergency sump. I'll be helping to install one for my neighbor, hopefully in time for the spring rains, and I'll try to document the procedure with words and pictures. Her AC sump failed and swamped her basement during the most recent bi-annual 100 year flood. (-:

It's really simple. Mount it above the existing pump so that it only activates when the main sump fails and the water level in the sump rises high enough to reach the emergency sump's activation switches which are housed in a safety cage to prevent debris from interfering with the floats. I screened my sump cover because it's outside at the base of a stairwell and it can collect a bag full of leaves in a day or two in the fall.

-- Bobby G.

[Ranger Gord]

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The answer is the NexPump Intelligent Sump System. It uses high efficiency pumps that pump twice as much as other.

[Robert Green]

Isn't the real downside of a water powered sump pump that you're adding more water to the effluent in what could be a torrential rain? I agree that if there's nothing else available they would be OK but a 12VDC pump will do a great job without adding to the flood.

-- Bobby G.

[tnom]

$1200 without batteries. $1800 with

[tnom]

A typical sump pump operates well below 50% duty cycle. More like 10% during a very heavy rain storm

[tnom]

A computer UPS is not made to handle the startup currents involved with motors. The "U" in UPS will be voided quickly as the unit will not last long.

[tnom]

[Robert Green]

They do look quite interesting albeit a bit pricey and I have to wonder if there aren't some jurisdictions that don't allow them. A cursory Google search didn't turn up any bans on them, but it sounds like the kind of thing at least some local government somewhere might take offense to.

Basepump Model RB750 $299.00 Basepump Model HB1000 $359.00 Basepump Model CB1500 $459.00

I wouldn't say my "big box" battery pump is a gimmick. It does the job, the costs to maintain a charge are pretty low and I have enough spare 12V battery capacity that I could probably handle anything short of the storm surge from a hurricane. I still find it troubling to add from 7 to 15 GPM of city water to the discharge because I'll probably have to pump it back out when it percolates through the ground. Still, if it's only an emergency backup to be used if the power fails, that's probably a better deal than a swamped basement.

I haven't read through the site thoroughly enough to know, but am guess from the size of the units that they operate via the Venturi principle. Do you know if that's true?

-- Bobby G.

[Robert Green]

Egads! You're right. Been there, done that, watched all the stinky magic smoke escape.

It would take either a specially designed or relatively large and expensive UPS to handle that momentary current surge. The conversion loss alone (from DC to AC) makes it worthwhile to get a DC powered sump pump instead and even consider using that as a primary. Battery powered sump pump technology is pretty well advanced thanks to all the boaters in the US.

Another advantage to using a battery or water power sump pump is that they would take over in the case of a power failure, pump failure or even sump overload (with a separately attached effluent pipe). Decided on two pipes when a neighbor's sump pump failed when critters got into the drain pipe and plugged it remarkably tight. That was after the big local drought two years ago and the pump probably didn't run for months. Two completely separate but complimentary systems seems to be the way to go.

I use my DC sump as a secondary but it always works when I test it yearly, which will be this week sometime. Battery needs monthly attention - wish I could find a cheap wall timer that allowed for "turn on charger for 6 hours every 30 days." So it's an item on a monthly checklist instead. I don't like leaving large batteries on chargers indoors 24/7 so I don't quite have it hooked up the way the manufacturer suggests. Hmmmm - maybe a lawn sprinker timer would work.

Overall, the water-powered sump pumps strike me as a great alternative in terms of simplicity and immunity to power failures but their downside is adding water to the effluent and high initial cost. Unlike other sump solutions, plumbing is required to attach it to the cold water pipes as close to where they enter the house as possible. I would't even think of using a model without a vacuum breaker. I also wonder what happens if for some reason someone leaves the water running. Also not sure if they are code in my area - of course this question came up at 7PM on Friday so I'll have to wait until Monday to call and find out. Maybe I'll just call some local plumbers. They'll know.

-- Bobby G.

[krw]

"Biannually" is a synonym for "semiannually". "Biennially" has only one meaning (every two years), however.

There are 10 kinds. Those who know the binary number system and those who don't.

[matthiasyuan]

replying to David Nebenzahl, matthiasyuan wrote: For motor drive that you need a low frequency UPS not electronical transformer as the critical work situation and motor's feature, I was an Engineer work for E-TON(the biggest company of UPS) years, I can make stable and low price UPS,