If you live near the East Coast, you probably suffered a power outage during Hurricane Irene. If you require a sump pump to keep your basement dry, you might have had basement flooding, too. My family was very fortunate to experience only minor flooding, compared to the more serious and devastating flooding that others have endured. We are very thankful for that. This experience has made us think about how to keep our sump pump running during a power failure. Whether you chose to do it yourself or seek help, I believe the overview of these alternatives will be useful to you. With apologies to my electrical engineer friends, I have tried to minimize the technical details and jargon.
The first alternative is a back-up pump powered by a marine battery. The general idea here is that you put a secondary, battery-powered pump into the sump hole, with the float a few inches higher than the primary pump. During normal conditions the battery is constantly charged with commercial power. The advantage of this approach is that human intervention should not be required during a power outage. The primary pump fails and the water rises to turn on the backup pump. Theoretically this could get you up to seven to twelve hours of pump use. But two friends of mine experienced the two disadvantages of this approach during Irene. In one case the water rose too quickly and flooded out the battery. In the other, the battery had not been properly maintained by monitoring the fluid level and occasionally putting it through its charge and recharge cycles, so it didn’t work long enough to be useful.
The second alternative helped us. A good friend appeared with a power inverter, which changes the direct current from a car battery into the alternating current required by the sump pump. We used cables to hook up the power inverter to his car battery, plugged the extension cord into the inverter, and ran the cord down into the basement to power the sump pump long enough to pump out our basement. As long as there is gasoline to power the car and recharge its battery, this could continue for quite some time. The advantages of this approach are that you can do it yourself and the cost is modest. You can get a power inverter to run a sump pump for less than $100. But, as I found out, getting the accompanying cables can be a challenge, so you need to be sure to get them from the same source as the power inverter.
The third alternative is a gasoline-powered generator. You have two choices as far as physical size. The larger ones are less expensive. For example, I found a 4000 watt generator for under $300, but it was large and did not have wheels, so it would be very difficult for me to move. The light weight ones are less than 50 pounds, but a 3000 watt version might cost over $2,000. The larger ones have a large tank for gasoline but some of the smaller ones have a siphon device that will draw gasoline from a nearby container. You will have two choices with respect to hookup. You can plug the sump pump into an extension cord connected to the generator. Or you can have an electrician install a separate circuit breaker box and do a backup wiring of all your essential appliances, including the sump pump, to this box, which would be powered by the generator during a power failure.
Regardless of the choice that you make, safety is a key concern. Electricity and water can be a deadly combination. As a few sample precautions, don’t let the power converter or generator get wet, don’t let the extension cords fall into water in the basement if you are there, and don’t try to push a three-prong plug into a two-prong chord.
http://www.basement-repair.com/equipment/equipment-backup-sumppumps.html
http://electronics.howstuffworks.com/gadgets/automotive/dc-ac-power-inverter.htm