Battery backup sump pump

Old 10-20-05, 08:14 AM
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Battery backup sump pump

I have a house with two sump pumps in the same pit. One is supposedly for backup purposes, but it's still operated from electrical outlet. Why would previous owners install this set up I don't know.

I would like to have a battery backup for sump pump in case of power outage. Can I just plug in one of the existing sump pumps into the battery, or do I need a totally different pump? What else do I need for this and what are the costs of items and installation?
Old 10-20-05, 10:05 AM
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In general, cannot just plug the existing AC pump into a battery. First of all, unless you are talking about installing a power inverter, there is no 110 outlet on a 12V battery. Second, if you are thinking about an inverter, you would need one with sufficient wattage capacity to handle the requirements of the pump's AC motor. Most 1/3 hp sumps will need at least 8 amps to operate. Unless you are willing to invest in an inverter that has a minimum 1000 watts (non surge), the inverter will not handle the load. There are some sophisticated systems (ex. Sumpro) which have a built-in inverter They have the ability to automatically switch the AC powered pumps to DC power in the event of a power outage. There are some "low" wattage utility pump you can buy that run on as little as 400 watts, but those are not pre-equipped with float switches.

From a cost standpoint, you're better off with a 12V DC battery backup sump system. The pumps are usually smaller, plastic, etc. with reduced pumping capacity, but will hopefully still provide enough power to keep you dry. Such systems are sold by several manufacturers....Basement Watchdog, Zoeller, etc.
Old 10-25-05, 02:01 PM
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i`ve got the 12volt watchdog that also has the built in battery charger , it works great. it was about $400.00( their battery cost $100.00) and it took me about 2 hrs working by flashlight one night when the power went out and got it hooked up just time.
Old 10-25-05, 04:46 PM
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I guess if I were you I would not even consider a "Battery Back Up Sump Pump". Reason you may be asking is that it is not a guarantee that they will work when needed. As with most homeowners, we don't always check on things when we are supposed to. If it is out of sight, it definitely is out of mind!

I would recommend a good water powered sump pump backup like the Guardian. This is just one of several brands on the market, normally available through a plumber since they don't sell these over the counter through a plumbing distributor. They are not cheap, runs about $450 - $500 but this must be plumbed into a 3/4" line, and installed before going to any fixtures or tees. Labor on these can be $350 plus. The water pressure from the city powers this and does quite well - for every gallon of water used, 2 gallons is pumped out. It requires a 1 1/2 PVC pipe for discharge.It does come with a Backflow Preventer for the water inlet pipe but you will need to get a check valve for the 1 1/2" PVC line. It can lift the water up to 15 feet at 407 GPH. At 10' it is 580 GPH. It does have an adjustable float that is placed adjusted just above your existing sump pump. So when the power does come back on, your's would kick on and the back up automatically shuts down. Simple and very effective.

I am an advocate of this and have installed many, especially after a client calls and says their battery back up failed. What usually happens is the batteries fail or if wired in on its own circuit, the power goes out, breaker trips and it doesn't recharge. Other cases, the batteries have just failed. If you don't check on it, you will have problems. At least the water pressure is more of a guarantee than the battery backups. I stress this is just used as an Emergency Back Up.

Drawback is that if you have a well, this is not the system to use. At that point, the Battery Back Up units would be the choice to use.

Hope this helps!
Old 10-27-05, 02:16 PM
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I have jus psoted a message on such pumps. I have extensively researched this subject the last few days and came to the following conclusion:

a)Water driven back up pumps are propably the better solution than battery powered.
b)But here we have two types of water driven sump pumps:

Installed Down inside the pit where the main pump is
Installed any number of feet Above Pit

The latter have some considerable advantages over the more standard ones which are installed/operated down inside the pit.
Since they are above the pit, the Municipal water pipe joins the pump at that location to drive the suction, all you have is a straight pipe from the pit up to the pump to aspire the sump water and draw it up into the pump from where it is expused through a discharge pipe to wherever you decide to lead the discharge. Run it to the outside or lead it back into the main-discharge through a Y connector.
Advantage 1) No floating debris will enter the critical parts of the pump where pressurized water mixes with Sump waterpump since its outside the pit.
Advantage 2: Since the Municipal water does NOT enter the pit, the pump only has to pump out the Sump water, hence its Sump capacity is at least doubled. The other model allows Municipal water also to collect in the sump, so it must pump twice as much water, sump and fresh water, the propellant.
Old 11-01-05, 04:44 PM
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Originally Posted by WannaKnow
I have a house with two sump pumps in the same pit. One is supposedly for backup purposes, but it's still operated from electrical outlet. Why would previous owners install this set up I don't know.
I can solve the mystery for you. I used to live in a rural area that has a high water table. It's very common there to have two pumps in the sump well, one sitting on a brick or other platform. If the main pump burns out, the 2nd one kicks in as soon as the water rises that little bit higher to activate its float. An alert homeowner would notice the difference in sound. In may case, the sump was in a crawl space where I never went unless I had to.

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