If you slow charge (about 2 amperhours) you will not cook the plates that are inside the battery. Depending on the deep cycle rate of the battery will depend on how long you will achive a full charge. With the battery that I have, it will take about 24 hours to charge on the 2 amp setting.f you slow charge (about 2 amperhours) you will not cook the plates that are inside the battery. Depending on the deep cycle rate of the battery will depend on how long you will achive a full charge. With the battery that I have, it will take about 24 hours to charge on the 2 amp setting.