battery backup sump pump.

[nathan.stowe]

Hey Guys,

I am looking for a battery backup for 1/2 hp sump pump.  I have an old rack mount APC that I am considering getting some trojans or something for, instead of the small internal array of batteries. 

Does anyone have connections to a dealer still?  or a better idea?

Thanks

Nathan.

[simon.gibson]

Normally you'd have a DC motor on a backup pump with a charger maintaining the battery.
With a 1/2 HP motor, that's about 400W. You're probably gonna need a backup that can provide 10 A. So you'd also have to figure out how long you need it to run to properly.

[bob.kaplow]

The other advantage of the seperate DC pump is that if the main pump ever fails, you still have a second pump to prevent flooding.

[jeffrey.miller]

Like the others have said, a DC pump is far better, so long as your only goal for the UPS is to run the sump pump.  Plus UPS take some power all the time, where the DC sump pumps really don't take as much. 

If you want UPS batteries I shop for them at Battery Sharks. 
https://www.batterysharks.com/
I have a large UPS that I built out a 120VDC 100AH pack for, but it runs my full rack of computer gear.  https://www.batterysharks.com/
They sell the batteries for your UPS if you want the normal ones too.

My opinion, if you are putting in a second pump, I suggest putting a second line out of the house too, if practical.  Occasionally the check valve fails and you won't know it because the primary pump is still working, but when you need the backup it just pumps water down through the other pump and back into the pit.  Also the DC pump will kick on if your primary pump fails / gets clogged with mud / etc.  So the DC pump protects you from two different issues, power outages, and primary pump failures.  Also the DC backup pumps have an audible alarm when they are running, so you hopefully notice if it's running and the lights are still on. 

[mike.scott]

I live in a house with no basement, so not an issue for me.
If I ever had a sump pump, I would look into a water-driven pump.
This uses your water supply and while not as efficient as an electrical pump and not much good if you use well and pump, city water hardly ever fails.
From what I've seen, it seems that either the power outage exceeds the battery runtime, or the battery is near end of life when called into action

[bob.kaplow]

As you point out, it's useless for those of us on well and septic, which is my case.