# battery life for sump pump



## sisyphus (Sep 20, 2011)

Hello all, does anyone know how long a battery on a back up sump pump will last after the power goes out? hours? days? thanks


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## BridgeMan (Sep 21, 2011)

We had one installed in our last place, in Washington state.  Should never have bought the place, but that's another story.  Lots of rain, yard sloped towards the house, lots of power outages, etc.  

The battery that came with ours was a very large, 12-volt thing (like a car or truck battery), that was supposedly kept at full charge by being plugged into the AC wall outlet, using an in-line rectifier/transformer.  We had lengthy power outages, and the longest lasted more than a day.  Judging by the depth of water in the basement, the battery didn't keep the pump running very long (we weren't living there anymore, and the place was vacant).  Best guess was about 4 or 5 hours, cycling on and off every 10 minutes or so, before the battery died.  

Best to have a standby generator handy, to plug the sump pump (and a few other essential things) into.


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## Redwood (Sep 21, 2011)

There are a lot of it depends when it comes to answering that question....


Battery size
Battery condition
Battery capacity
How much the pump draws
Pump capacity
How often the pump runs and how long it runs
How much water is coming in

Just a few things to consider...
Not all pumps and batteries are created equal....


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