On our first “Hump Day-Pump Day” we talked about sump pumps. As we learned, a sump pump is a very necessary item, especially when there are heavy rains. So, what happens when your electric goes out during a storm? Or when your sump pump just fails? Without a functioning sump pump, the rain water will eventually flood your basement. Just a ¼” of water, which is about 156 gallons per 1,000 square feet, can do great damage. It will soak your carpet, into wood molding the bottoms of cardboard storage boxes, furniture legs, etc. So if your sump pump fails to work during a storm, wouldn’t it be comforting and practical to have a back-up system? Fortunately, there are two sump pump specific products on the market that can help you out… This week we’ll look at battery back-up sump pumps.A battery back-up system is a small, secondary pump operated by a 12 volt DC, deep cycle marine battery. It is not intended to be the primary pump, nor can it operate indefinitely under battery power.
The illustration shown depicts a typical battery back-up sump pump system.
The system consists of:
• Small 12 volt pump
• 12 volt deep cycle marine battery (typically sold separately)
• A float switch/alarm
• A charger/controller
• A battery box
• A tee with check valves
• Associated wiring
The pump is installed in the sump and connected to the discharge pipe of the primary sump pump. The float/alarm is mounted above the primary pump. The charger controller keeps the battery charged and, on some models, sounds an alarm when the back-up pump kicks on. In addition, on some models, the controller sounds an alarm when the battery charge drops. The system operates in this way: When the primary pump fails, water in the sump rises above the “on” level to the level of the float switch. When the float switch rises it energizes the back-up pump and your basement is saved from drowning. Of course, the battery will eventually use up all of its electrons and the back-up pump stops running. My experience is that a fully charged battery will operate the pump for approximately 8-10 hours, which is plenty of time to have our plumbers out to replace the failed pump or to safely run electric to the pump from an exterior generator. There are some models that use two batteries, thus doubling your running time. Check it out, and check back next week for a (shorter than these first two, I promise!) post on the other type of back-up sump pumps.