The performance of lead/acid batteries can be improved considerably by modifiying the design according to certain criteria. One of the problems that have been detected is the low ratio of the volume of electrolyte to the amount of active matter content in that plates: with this goal, the influence that a greater quantity of electrolyte, in relationship to the active matter to be used, could have on the behavior of the battery, and especially on its capacity, has been studied. The tests carried out in this sense proved that the increase of the quantity of available electrolyte improves the behavior of the battery by increasing the discharge capacity between 5% and 20% depending on the discharge current. This increase in capacity is directly related to the increase in volume of the electrolyte. The addition of extra electrolyte from an external tank with electrolyte recirculation presents considerable advantages over the extra electrolyte addition into the battery casing.