check out these _types_ of batteries. http://www.sbsbattery.com/products-services/by-product/batteries/batteries-flooded-wet-cell-batteries/flooded-wet-cell-ba

check out these _types_ of batteries. http://www.sbsbattery.com/products-services/by-product/batteries/batteries-flooded-wet-cell-batteries/flooded-wet-cell-batteries-stt-series-flooded-2v-cell.html http://www.sbsbattery.com/products-services/by-product/batte... no recommendation on the supplier, but funny thing, the power companies and telcos have already figured this out for reliable DC power :)