With a 4 lead acid battery configuration, 2 in series loading 2 in parallel via a joule thief circuit , like shown in the attachment , it may be possible ,to charge the batteries by themself.
Notifying the ringing effekt , that causes energy be drawn from the ambient.
Ossi's circuit (experienced guy)
Imho it's not advantageous to apply a load during the charging process, because the dipole is destroyed then.
So remove the parallel stack , apply a load to it and write down volts amps and duration
(Energy consumed).
Then put the paralell stack back into the charging circuit and charge it full.
Exchange series and parallel stack
(prior parallel batteries now in series, and series batteries now parallel) simple
Charge the new parallel stack. When it's loaded , remove it from the charging circuit and apply
the load. ... And so on. If the summary of the energy beeing drawn by the load exceeds
the capacity V * Ah of all 4 batteries you have your OU circuit.
http://www.overunity.com/downloads/sa/view/down/487/http://www.overunity.com/downloads/sa/view/down/486/