The performance and life of lead-acid batteries are severely limited due to sulfation in the negative plates. The addition of an appropriate form of carbon as an additive in the negative plate was usually applied to solve the problem. However, previous research conducted showed that lead sulfate is also permanently deposited on positive electrodes. Several other studies have also shown that the addition of carbon to the positive active material successfully increases the life cycle of the battery. This study uses two types of carbon that is self-made activated carbon and acetylene black. The purposes are to increase battery life and to find out more in the variables that control battery life especially the role of carbon in positive electrode. This research begins with the manufacture of activated carbon from charcoal and bought acetylene black. Both types of carbon will then be coated on the battery's positive plates. Testing were done using 8-channel battery analyzer. The results show that the coating using acetylene black gives a better life cycle effect compared to the positive plate coated with activated carbon from coconut shell charcoal and standard plate.