Battery bank sizing

peter

Thanks for all the help in my last post . The batteries (down to 8 l16's) have been limping along this summer but I a m going to have to replace soon. They are acting very weird with low sg readings and higher non-corresponding voltages. In the past I have had 12 batteries with 10 170 watt panels and an outback system. How can I tell if 8 new batteries would be an appropriate size bank in the future? It seems ok for our small energy conserving house and they are really expensive.