How Many Volts is a Marine Battery?

We often hear the question of what the proper voltage level is in a fully-charged marine battery. In the case of OPTIMA batteries, there are two correct answers, because we offer two different types of marine batteries. Our 34M BLUETOP marine battery is a starting battery with a dark gray case, that is designed and warrantied for use in applications that involve starting your engine. All of our other marine batteries (D34M, D27M & D31M) are all designed and warrantied for both starting and deep-cycle applications. So what does that mean in terms of voltage levels?

Our 34M BLUETOP is fully-charged at about 12.6-12.8 volts and all our other BLUETOP batteries are fully-charged at about 13.0-13.2 volts. If you are using another brand of battery and don't know what the fully-charged voltage level should be in your battery, the safe minimum level for a fully-charged 12-volt lead-acid battery should be at least 12.6 volts. Equally as important as knowing your fully-charged voltage level, is keeping your battery fully-charged at that level whenever possible. Proper voltage maintenance will improve the performance and lifespan of all batteries and a microprocessor-controlled OPTIMA charger or maintainer will do a great job of properly-maintaining battery voltage in any marine battery.