Im inclined to agree george65 ! I have wondered for years why a large lead acid cant be built economically , I mean cells the size of those big blue screw top 44gallon drums . A circulating pump pumping the acid around through a filter will balance the charge of six of them giving a nominal 12v , with shit loads of capacity and its easy to make hydrochloric acid over time , so why not the only problem i see is the spongy lead for the plates but then theres recycling of old batteries they are made from a paste type compound and plastered on to the plates . any thoughts out in invention land ?? lets hear them