A continuously running machine is not generally the goal. The goal is energy for free. My understanding is that a device which uses principles that violate laws of nature cannot be patented (in this case laws of thermodynamics).

The salt water battery is essentially what is going on in a dry cell. The dry cell has the advantage of a higher stored energy density by using more efficient electrolyte and electrode combinations. So if you asked someone to take the principle of the saltwater battery and develop into something more useful they would come up with the dry cell we have to day.

Your method for "recharging" the battery by rebuilding it has many practical failings. You have dramatically increased the price of lead and sulphuric acid through demand so your prices are unpredictable at best and definitely higher than quoted. You have also added a labour content to your battery rebuilding - not everyone will have the tools and skills to safely handle the materials involved. There is also an additional cost in manufacturing safe rebuildable wet cells. Then you have a disposal cost of all that PbSO4 (nasty stuff - particularily for young children). The rebuild company can extract the Pb and SO4 and sell it to you - but they'll do this in their own big battery using just as much electricity that you would have used charging it yourself. Do the economics and then I'll see if a rebuild is cheaper than a recharge. Further, a recharge is way more convenient.

Does the .12cents/pound of Pb include manufacturing costs to make the matrix and are you including the PbO2 plates as well - cause you'll want those.