Battery for backup sump pump

We do have a generator that would run the main pump.

Claimed capacity of the "Basement Watchdog" unit is 1000gph with a 10ft lift. The smaller of the two batteries is claimed to be able to run the pump for 6 hrs continuously; the larger battery for 7.5 hrs continuously.

Perce

Where it either runs back in or into the already overloaded storm sewer - which then still gets back inside.

Thats on a new battery, and full battery power is over 70f, if yours died in 6 years figure what its pumping in 3 years, get a real charger- float charger you can calibrate.

Yea, Battery powered pump =3D flood.

If thats the case nothing works for your situation, But water powered just makes sense, it out performs and works when needed. I also bet the electric cost of a 24x365 charger is noticeable, figure in 5 years of that, new batteries and crappy chargers that ruin batteries. It should be called the Basement Bitch, it will make you pay and only perform when happy.

e:

Geez, talk about jumping to conclusions. I've seen lots of sump pump installs where the water neither runs back in nor goes into the storm sewer system. For example, it simply gets discharged 20 ft away and disipates down a grade away from the house in the backyard. Ransley's water powered recommendation could be a good solution, depending on the specifics of the actual installation.

I found a 75AH sealed lead-acid battery with the "Campbell Hausfeld" brand at Menards with the sump pumps. Not cheap, but it won't have to be topped up -- and it fit in the bag, which got me a 15% discount.

Perce

No, it'll just boil dry. Unless you are willing to get a decent charger, don't expect a battery to be there when you need it.

I don't see that a charger fed from a 900mAH wall wart could do much damage to a 75AH battery even if the controller circuit didn't switch from "charging" to "charged" (i.e., stop charging) for long periods.

And the idea of the sealed lead-acid battery is that the hydrogen and oxygen generated get recombined in the cell to form water again.

Perce

You need to learn about crappy chargers, a wall wart can put out anything and everything, you think because its small it cant do harm, thats funny. It can ruin a battery in less than a year if not operating to the batterys specifications.

To which I'd add, I doubt the wall wart is 900 mah as their rating doesn't have a time component.

there are many web sites that explain the problems of over or under charging a lead acid battery...here is just one..

No. That is wishful thinking. Sealed just means you can't add water. The hydrogen and oxygen still get boiled off, there is a vent somewhere on that battery. 900ma at 120v is 9a at 12v. That can definitely do damage.

If they combined as you suggest, there's be a fire, possibly an explosion.

That's not what the manufacturer's description says.

Even if the controller did not switch out of charge mode for long periods, 900mA is hardly any more than a "float charge" rate.

Perce

Joseph Campbell There is a difference between sealed flooded cell lead acid and recombinent AGM batteries. Recombinent agm batteries are "starved electrolyte" batteries and unless grossly overcharged do NOT lose water or boil dry. They DO have a limited lifespan, but 5 years on a properly sized and set up unit is not a stretch - and the charging system does not need to be "sophisticated"

Not so. They DO work. And catalytic caps are available for flooded acid batteries that do the same as long as they are not GROSSLY overcharged.

Joseph Campbell

Hmmm, I believe the op was talking about a sealed lead acid, he didn't mention AGM. I'm not sold on agm myself, I have one out in the garage with one terminal corroded beyond the point of utility. Nice idea, but just as bad as all the others from what I've seen.