Assuming they're on average at 90 % capacity, my "collection" of Enersys PowerSafe 12V170F batteries have a capacity of 5508 Ah at 12 V, 1377 Ah at 48 V, 66 kWh of total capacity, or 6,6 kWh of "safe" long-term capacity at a cycle depth of 10 %.
That puts the price:performance ratio of this bank, all-inclusive, at roughly 3 Euro per kWh. Perhaps 3,05 €/kWh if you include a new quarter panel in the price.
