Abstract: This invention concerns a method of increasing the available amount of acid at PAM and NAM in lead battery electrodes and still retain a short distance between the electrode surfaces. With mechanical support of PAM (for example in tubular batteries) in spite of low PAM densities it is possible to almost completely prevent the formation of mud. Spaces for acid should therefore be mechanically strong and supporting in order to retain unchanged PAM volume. In order to prevent that the porous bodies are filled with lead powder, lead sulphate or other components during manufacture, they may be impregnated with a filler material such as for example plastic or wax which is removed after forming the electrodes or after any other suitable process. The filler material may also be an inorganic salt which dissolves only at filling with acid leaving a desired porosity.