Nowadays, lead acid batteries still offer a reliable and cost-effective solution compared to lithium-ion batteries, which can be adapted to different types of energy storage applications. After more than 150 years of use, the energy density of these batteries still presents substantial room for improvement. Our research group is monitoring the processes, which occur inside lead acid batteries (ad hoc manufactured small and commercial batteries) in an operando manner. To study their behaviour, we have used thermal and fission neutrons, as well as gamma radiation to perform both radiography and tomography of lead acid batteries with the goal of better understanding their function and subsequently improving their electrochemical efficiency. The type of radiation used can resolve different information. For example, thermal neutron radiography shows that electrolyte stratification is difficult to detect, due the neutron transmission not appreciably changing in the working concentration range of the electrolyte. However, by focusing on the electrodes, evidence for structural and electrochemical evolution in the active materials can be detected based on compositional change. Here, we present a summary of the recent advances we have obtained thus far from experiments performed at DINGO (OPAL reactor, Sydney) and NECTAR (FRM-II reactor, Munich).