WAYNE ESP25n - 12 Volt Battery Back Up Sump Pump, Battery Not Included - Up to 2,700 Gallons Per Hour - Heavy Duty Basement Sump Pump

Our basement must have been built in the path of an underground stream. After a big rain, water will continue to come into the sump for several days after the end of the rain. Basement flooding is a certainty if the sump pump isn't working. So AC power, or no AC power the sump pump must continue to run!The AC-powered pump component is typical of good quality flooded pumps, powerful and quiet. But it is the DC-powered backup pump that sets this unit apart. We've had other DC-powered backup pumps, but they typically fell short. We have about a 7-foot lift between the top of the sump and the ground surface where the water is discharged. The other backup pumps would run, but strain to remove the water. Not so this pump. The backup pump design is very similar to the primary AC-powered pump and takes only about 30 seconds to empty an 18" round 30" deep sump against that 7-foot (minimum) head. In a recent test following a 4" rainfall event, the backup pump was needing to empty the sump about every 3 minutes during the peak drainage. It ran on battery power (admittedly off a 100-amp-hour AGM battery) all day and through the night without any visible drop in the battery voltage until there was no more water to be pumped.With one caveat, installation is easy, primarily because the plumbing interconnecting the two pump units is built-in. The caveat is that the base of the unit is massive, with the two pumps mounted side-by-side (instead of vertically as many of the lighter-duty units are). We have an 18" circular sump and it just barely fit - in part because while 18" was ample for the center of the unit, the corners just barely fit.We did make one alteration. We are charging our battery using a high quality, stand-alone charger. Why? The main limitation on battery life is likely to be how it is charged (or, if things don't go right, overcharged). The built-in charger may be OK, but given the cost of the battery, we thought investment in a computerized low-amperage charger was a reasonable one. The good news is that the pump control electronics built into the battery box work fine with the AC charger cable detached. The charger type makes no difference when the backup sump pump is actually running, because, by definition, the AC power will be off at that point anyway.Given its solid design and construction, and that it seems to do the needed pumping with little evidence of effort, I'm expecting this unit to keep us dry for many years .

Quite the impressive setup. The main pump is the same high quality pump that you can buy standalone on amazon, and is ultra silent (inaudible besides the sound of rushing water) and powerful. The backup pump is a smaller plastic DC pump but appears to do a good, albeit slower, job pumping. Each pump has a check valve attached right to the output and the backup pump float is already mounted on the Y pipe. All you need to do is set the pump in your pit and hook up the Y pipe to the existing pipe.You do not need the special Wayne battery to put in the battery case. Go to your local fleet/farm store with the empty battery case and find any maintenance-free AGM battery that fits (check that the cover fits as well). I found a Road Runner model AGM27 92 Ah battery for cheaper than the 75 Ah Wayne one here on Amazon and with a better warranty (36 month warranty and 18 month replacement). The battery case comes with industry standard bolt-down connectors.So far the only downside so this setup is that the alarm on the battery box has no test button and no silence button. Its still easy to test by unplugging and filling the sump hole up with water, but there is no way to silence the alarm when its in backup mode.Some tips when putting in the new pump: since you need to glue a pipe into the Y-connector, don't glue the new pipe to the existing pipe. Instead use a 1.5" rubber connector with screw tighteners ($2-$3). This will allow you to remove the whole pump assembly in a jiffy should something happen. Also, do yourself a favor and clean out the bottom of your sump pit with a shop vac if you have the plastic bottom pit type. Mine was full of sand that had come in through the holes. This isn't an issue for the main pump since it doesn't pull water in through the bottom. However, the backup pump sucks in water through the bottom and probably wouldn't last as long if it had to suck up sand and other debris.