What is the Difference Between a Marine Battery and a Car Battery?

OPTIMA Batteries
Milwaukee, WI
Are all 12-volt batteries created equally? No. In the case of OPTIMA Batteries, our REDTOP batteries are designed & warrantied for SLI (starting/lighting/ignition) applications. Basically, that means they're supposed to be used for starting an engine. OPTIMA YELLOWTOP batteries are designed & warrantied for those starting applications, but also for deep-cycle use. So where do the BLUETOP marine batteries figure into the mix?
Most OPTIMA BLUETOP marine batteries are designed and warrantied for both starting and deep-cycle use, like trolling motors, live wells, big stereos, etc... just like our YELLOWTOP batteries. However, one BLUETOP battery, the 34M (pictured above), is the marine version of our REDTOP battery, which means it's designed and warrantied for use in engine starting applications, but not deep-cycle use, like trolling motors, etc... So is that the only difference between OPTIMA marine and automotive batteries? Definitely not!
All OPTIMA BLUETOP marine batteries come with both SAE terminals and threaded post terminals, which are more commonly used in marine and RV applications. However, internally BLUETOP marine batteries are otherwise identical to their automotive counterparts. So if the batteries are basically the same inside, why are the warranties different? The short answer, is because people tend not to do a good job of taking care of their marine and RV batteries.
The free replacement warranty on OPTIMA BLUETOP marine batteries is two years in consumer applications, but the free replacement warranty for YELLOWTOPs and REDTOPs in consumer applications is three years. When any 12-volt lead-acid battery is discharged below 12.4 volts and is left sitting in that state, sulfation begins forming in the plates, which diminishes both capacity and lifespan. In applications like boats and RVs, that tend not to see continuous use, that makes it very important to keep battery voltage properly-maintained with a quality battery maintenance device.
If any battery is going to fail because of a manufacturing defect, it is likely to do so well within the first few months of use, if not the first few weeks. Beyond that time frame, battery warranties largely serve a marketing function. We know this, because many of the batteries returned to us under warranty are just deeply-discharged and work fine, when properly-recharged. However, if a boat owner doesn't keep their battery voltage properly-maintained, the sulfation that builds up will eventually lead to premature failure.
So what can you do to maximize the performance and lifespan of your marine and automotive batteries? Keep them fully-charged whenever possible. Our REDTOPs (and the 34M BLUETOP) are fully-charged at about 12.6-12.8 volts, while our YELLOWTOPs and BLUETOP marine batteries are fully-charged at about 13.0-13.2 volts. Don't wait until the night before you are going to use your boat or RV to charge your batteries. Fully-recharge them as soon as you get home and keep them on a quality battery maintainer until you need to use them again.
We know using good maintainers are worth the investment and we're willing to encourage that use, by offering an additional year of free replacement warranty coverage on any battery purchased directly from us, if someone purchases an OPTIMA Digital 1200 charger & maintainer from us at the same time.