This work deals with the study of influence of additives added to the negative active mass of the lead-acid battery electrode. Specifically, it’s studied the influence of acrylic fibers (1,5wt.%) and different amounts of carbon CR 2996 on the final properties. Carbon was added in an amount of 0.15; 0.46; 0.78; 1.4; 2.65 and 5.15wt.%. It was performed formation, depth of discharge cycles (DoD) and partial state of charge cycling (PSoC). After 12 DoD cycles it was drained excess of electrolyte from the battery and it was performed another 7 DoD cycles. Thanks to these cycles it was possible to verify the actual capacity of electrodes. The results are shown in relevant graphs.