Battery Backup Guide

Todd asked:


I am thinking of getting a standard car battery and a 400watt inverter to use for backup power. How long do you suppose I could run my laptop from this setup with the battery at full charge?

Bartholomew asked:


The battery in my APC backup unit is a few years old and lasts only like 3 minutes before shutting down. Rather than buying a new battery from APC, is it possible to buy a car or marine battery and hook it up to the UPS unit?

I did a quick search on the web and got the following page which makes it sound like you can swap the 12 volt battery in just about any UPS with any 12 volt car or marine battery. They make it sound really easy:

http://saltaquarium.about.com/od/emergencypowersources/ht/ht_aqups.htm

Is this possible? It would be great if it could work. Rather than have a few minutes of backup power, I could have whatever a car battery can provide (hours?)!

Are there are any hazards to watch out for? Can the UPS even charge something as big as a car battery?

I took out the old battery in my UPS just to look at it, and I see 3 terminals coming out of the battery! Three? Isn’t there supposed to be just 2 terminals, a positive and a negative? Can I hook a car battery to this?

JAGGI asked:


I need the time for 600 V inverter with 80 Amps and 100 Amps battery