Is Wet/Acid Battery for Backup Sump Pump Safe Near Flame?

[chet everett]

Sorry to hear about your lack of confidence Harry. My real world experience, of having had multiple homes with sump pumps and battery powered back-up systems, has shown that a nice self monitoring charger will last through 99%+ of any rainfall induced power outage. The pump is optimized to run off DC for at least 8 hours, which is generally enough time for anybody with a sump pump to track down alternative sources of power, like a generator.

While the "theory" of using a municipal water supply as a back-up sump is not too bad what I have seen in PRACTICE is that unless the SUMP DISCHARGE is basically over the side of a CLIFF the fact is 3::1 ratio you will soon turn your yard (and your neighbor, and their neighbor, and their neighbor) into a GIANT lake of EXPENSIVE municipal water -- PROS AND CONS OF WATER POWERED SUMP PUMP | Aaron Kramer Plumbing
The ultimate if of course a full-on AUTOMATIC BACKUP GENERATOR and MULTIPLE SUMP PUMPS, it is all in how costly your finished basement "protection system" needs to be -- Generac QuietSource QT04854ANAC Seriesâ„¢ 48 kW Standby Power Generator Premium-Grade CA/MA Compliant

SUMPRO SUMPROPLATINUM Platinum Combination Battery Backup System

[harry chickpea]

If someone is pumping over a thousand gallons of water an hour out of a basement, as your link would suggest is common, methinks there are problems besides sump pump size. If you tell me that a battery will pull 8,000 gallons of water up an 8' lift, I cry bunkum.

[chet everett]

Neither a 12vdc electric nor water siphon pump run continuously. They are designed to switch "ON" when the sump is near full (well above the "non-backup" level...) and "OFF" in a similarly brief period. The more water that is removed when either is "on" the more "working room" there is for the sump to again fill up.

Typically a deep-cycle battery are rated around 50-80 amp hours. The best 12v pumps draw around 6-12 amps while they are running, and ideally only run a few minutes per hour, thus they provide "back up" capacity to the sump of about 8 hours. Each "slug" of discharge gets a pushed out and even in very heavy rain there is typically a "break" for the ground to try to absorb the water...

The siphon will run much more frequently, becuase with each cycle it can't discharge as much as the electric pumps -- worst case nearly continuously, and if it is raining in the yard the discharge, fortified with expensive municipal water, quickly becomes a problem.