Deep Cycle batteries are the backbone of any "OFF GRID" System.I have a special calculator on this site for understanding discharge and usage rates "very basically".http://windsolarhybridaustralia.x10.mx/batterycalculatorAH.html
Just one thing i didn't mention , was the fact that deep cycle batteries with their AH("ampere hour" rating) are actually lower in AH the heavier they are discharged.
For example a 12v 100AH battery discharged at 2KW (rate using 166amps continuous) will not last
100/166 = 0.602 of an hour e.g. 35 minutes approx.
It will in fact only last 15 minutes or less because of the physics of discharge.NOTE: in off grid systems never use a deep cycle battery AS a deep cycle battery , the heavier beef of them is to support high throughput as a joined array without damage in such a large economic investment! never discharge any one battery more than 1/10th of its ah rating (why arrays are used to raise the storage size).Linkback: https://www.ozfarmer.com.au/index.php?topic=1856.0