If you aren't a homeowner this is probably not even remotely cool.
http://www.basementwatchdog.com/combo_sump_pump.htm
Just put one in today. 5200 GPH combined (it's a revised model).
Primary 3200GPH pump runs off of 115V AC
Secondary 2000GPH pump runs off of 12V DC
If the primary pump dies, the secondary takes over. If the power goes out, the battery can run the backup for 6 hours straight- or days if it's used intermittently. The battery has its own battery tender and control unit that says if the battery is in use, needs distilled water added, if it's charging, and if the battery is toasted.
Just getting ready for the rainy season. The crusty POS that was in the pit was on it's last legs, I'm sure. Living so close to the Raritan River I was just a little concerned about the low water table and flooding LOL.
And it's ****ing
Chrome.