WAYNE - 1/2 HP Sump Pump with Integrated Vertical Float Switch and 12 Volt Battery Back Up Capability, Battery Not Included - Up to 5,100 Gallons Per Hour - Heavy Duty Basement Sump Pump System

I can honestly say that it works with both power options. Be careful not to connect the battery until after the pump is in place and the plumbing is connected. I made the mistake and received a huge blast of water. Fortunately my wife was not recording.I have tested the unit after installation by unplugging AC power and forcing the float to activate and the DC pump did the job. Make sure that you measure your pit before buying this because it will take more space than the old AC only pump. There are separate AC and DC pumps and separate float switches for each. You will need to adjust the pipe length for the output because in most cases the length of pipe needed for your AC only pump will be different than this dual pump.I personally installed this during a rain storm and the pit was almost full. I do not recommend this because you will be doing things in a hurry and might make mistakes like I did. . . I only got wet.Observations:1. The battery is not included so pick one up at Batteries Plus.2. You will need more than one AC outlet for installation because of the battery charger.3. The battery case and cover are not made well and do not fit together well. The cover just sits on top loosely.4. Make sure that you have all of your tools ready before you start. You will need screw drivers to tighten the clamps. You will need a saw to cut the output pipe to length. You might need other tools depending on your installation.5. I highly recommend installing a water sensor that will alert you even when away from home as a third level of protection.The photos include before and after. I also showed inside the battery enclosure. Yes, the battery is the size of a car battery.

UPDATE: In the original review (below), I said the electronics were a weak spot. This turned out to be true when the charger failed about 6 months in. I tried to contact them through their website to obtain a warranty replacement, but received no response even more than a month later. So I am reducing the my rating from 4 stars (original) to 3 stars for premature failure of the charging system and the lack of any kind of responsiveness.In the interim, I took my motorcycle battery tender and hooked it up to charge the backup battery. It worked great, though it took longer to top off the backup battery as it has a fairly low output compared with the supplied charger. But it did the trick.ORIGINAL REVIEW:This is for the combination unit with 12-v backup.TL;DR - This is perfect for replacing a single AC pump to add a backup. Installation was very easy and its performance was great when I needed it most. The charging electronics and indicator lights are a weak point, however.First, let me address a couple issues highlighted in other reviews.1) There are directions for testing the battery condition in the manual. You need to unplug the unit then press the test button to run the 12-v pump and test the battery under load. While plugged in, the charge status lights are virtually useless (as described below and the reason for the 4-start, rather than 5-star rating). But the testing process does work and will show a partially discharged battery under load.2) Check valve - The instructions require a check valve. The unit does come with valves at the base of each pump, but these are not intended as a replacement for a standard check valve in the discharge line. I believe they are simply to prevent the main pump from pumping water backward through the backup pump, and vice-versa.3) Pumps dead on arrival - mine were fine, but given a couple reports fo DOA pumps, I tested mine in the bathtub before installing. Pro tip: hold a bucket 6 or 8 inches above the discharge tube when testing. Don't ask me how I know this.4) Airlock - I had no problems in either bathtub testing or after installation. Your mileage may vary based on the installation.5) The charging system - I have no way to directly test the adequacy of the charging system, but the status lights are useless during charging. I have a battery tender for my motorcycle and that inexpensive device has far more informative lights which show fast charge, slow charge and maintenance. The light on this unit just glows green whenever it is plugged in, as best I can tell, regardless of the charging state. I ran the battery down to yellow during a protracted power outage, and when the power was restored the battery status light just glowed green. No indication that it was actively charging or just in maintenance trickle charge. Once life settles down, I will probably just buy a battery tender and hook it up in place of the supplied charger. I trust it more and it tells me what's going on.OK, now to my review:I bought this to replace a single pump in a 16" pit. This was a perfect unit for the purpose. Installation was super easy. It has a single discharge tube, which I easily retrofitted to the existing discharge tube (with check valve) from the original single pump. The unit fit in the 16" pit, but with not much room to spare. I'm glad I had an inch or to to maneuver the unit to position the discharge pipe. The unit looks and feels sturdy AF. It inspired confidence and didn't feel the least bit flimsy.The main AC pump is remarkably quiet and we had no issues in the short time we had power. Shortly after installation, we lost power for 3 weeks due to an electrical fire in the house. The backup pump performed admirably. Our sump pumps only run every few hours under normal circumstances, so there was not a huge load on the pump, be we had two large rainstorms and one heavy snow melt that tested the limits and the 12-v backup performed flawlessly. YMMV, depending on pump demand. Our sump is in an 8-ft basement pumping to ground level.Let's talk a little about the floats. The units come with pre-installed, fixed, non-adjustable floats to turn on and off each pump. Personally, the floats on the main pump were much better suited to our needs than the floats on the one we replaced, but there is no way to adjust the float level, other than to raise or lower the pump assembly by adding or removing bricks from the sump pit. The float on the main pump has separate "on" and "off" levels, which makes perfect sense. It waits until the water raises to a certain level, then runs until it falls to a certain level. The float on the 12-v backup, on the on the other hand, works differently. It is a single "on" float, but the unit runs an additional 10-15 seconds to avoid frequent on-off cycles. In my sump, this results in the pump sucking air for the last 5 seconds or so of the cycle. Not sure why they didn't include a similar float as the AC unit.The good news on the 12-v float is that it is set to turn on at a higher level than the main AC float. So if the main pump fails for any reason (power, mechanical failure, air lock, whatever), the backup will take over when the water level reaches a higher level. This make the 12-v backup a true backup for any failure, not just electrical failure.I'll post a separate review of the Mighty Max battery, but it is getting 5 stars. It arrived fully charged (as best I can tell due to the useless charging lights on the pump unit), it easily fit in the battery box, and it went 3 weeks under modest load conditions before the status light on the unit went to yellow (again, whatever that mean given the weaknesses already described for the charging electronics). No idea how much more juice it had left in it, but it was a stellar performer for the 3 weeks we were without power.Mighty Max Battery 12V 75Ah SLA Battery for Wayne ESP25 Back-Up Pump Brand Productby Mighty Max BatteryLearn more: https://smile.amazon.com/dp/B00OZMVI46/ref=cm_sw_em_r_mt_dp_U_BrohEbDZ40DVSIn summary, this is an incredibly easy replacement if you want to add 12-v backup to an existing AC only pump. The 12-v battery charging electronics and indicators lights are suspect to useless, but easily remedied by substituting a $20-30 battery tender.

I purchased this system and the separate Wayne CDU800 pump because I thought building my own Y pipe would allow me to fit the system in a very narrow sump. That worked well, as everything fit in a sump that is 14.5" wide at the bottom. The complete kit with both pumps specified a 16" minimum width. We had a power failure during heavy rain this week and the battery pump saved the basement. I purchased an AGM battery from a local battery jobber for much less than anywhere else and it's working two years later.Used the PumpSpy "Silent" Sump Pump Threaded Check Valve, 1-1/2" NPT to 1-1/2" Pipe on each pump. Also used the PumpSpy "Silent" Sump Pump Check Valve, 1-1/2" above the pump to ease future maintenance.

Well thought out system with integrated backup pump. Installation went well with no major issues. Connector from transformer was a little dainty and had to fuss with male side to get it to engage fully. The provided check valve leaked during my initial testing. Found the four screws holding the center section together were loose. Tightened and the leak stopped.Not a fan of the large transformer. Too large and heavy to plug into a wall outlet. Covers all the outlets on a power strip. Suggest changing to a corded transformer. That way the heavy transformer can sit on a flat surface and cord can attach normally. No change to low voltage connector so could be retrofitted into system.Overall very happy!

I installed this after my basement flooded when a old Zoller backup pump float failed. I replaced the whole system with this combination and purchased a new battery to start fresh. A little over a year later, the battery is doing well and the main pump is good to go. I thought the backup pump failed again. The float was fine, the battery is fully charged and I can manually activate the pump using the test button BUT in the confusion of pulling the old pump and seating the new one I didn’t connect the electric connection that tells the backup pump to activate. In the end, the minor flooding was my fault this time.I relied on the test button to test the pump’s activation but that will work without connecting the float sensor to the battery. Anyway, just follow the instructions and don’t miss the vital connection. I’ve updated my review to 5 stars from 2 because I was dumb, not the pump.