There have been simplified versions of this concept out there in DIY land for decades. I built two long ago. With certain batteries, I had some success in getting them back from the dead, at most seeing ~30% gains. However, the ones I made had to be run for months, non-stop, to make a difference. That, and the high frequency, extremely short voltage spikes were not kind, long term, to what ever charging circuit was keeping the batteries alive. A dumb solar panel with robust blocking diode seemed to be the best - intelligent chargers would burn out.