Ok so hear me out now. I do believe it is possible to create a constant voltage constant current source. The first LM317 limits volts to 14.1v and the second one limits current to let's say 100mA. When the "device" requires 50v to draw 100mA then the constant voltage will only allow it to draw as much current as 14.1v would allow according to ohms law. So as the "device" changes it's properties like resistance, the 2 LM317's will NEVER allow it to draw more than 100mA or be subjected to more than 14.1v. And I do believe a lead acid battery could be charged this way. It might take long but will still work. Does that not make sense?