you neeed to find out how many watt it use and how big is your battery I have forkleft battery old one I usually charge it every week and I use it for my house, tv, freezer, etc. Normal batteries usually last few hours if you have small sytem. you neeed to find out how many watt it use and how big is your battery I have forkleft battery old one I usually charge it every week and I use it for my house, tv, freezer, etc. Normal batteries usually last few hours if you have small sytem.

yes you can use 2 of them to last about 18 hours...

if one only without recheging it may last few hours...need to mnow how many amp your battery and how much use your system to be exact yes you can use 2 of them to last about 18 hours...
if one only without recheging it may last few hours...need to mnow how many amp your battery and how much use your system to be exact