Best Deep-Cycle Battery for Marine/RV 2024

A deep-cycle battery is a battery designed to be regularly deeply discharged using most of its capacity. In contrast to car batteries which only provide short bursts of energy, deep cycle batteries are designed to provide sustained period over a longer period of time. The mainstream battery types in solar battery backup systems include Flooded Lead Acid (FLA) batteries, Gel Cell batteries, Absorbed Glass Mat (AGM) batteries and lithium batteries. Depending on the voltage, deep cycle batteries are divided into 12v battery, 24v battery, and 48v battery. The most common deep cycle RV battery, boat battery, and marine deep cycle battery are 12V, and the deep cycle golf cart batteries are normally 24V or 48V.

In most cases, FLA batteries are an excellent choice for RE systems because of their cost-effectiveness, particularly for those systems which require a lot of energy storage. But FLA batteries do require maintenance! Regular monitoring and maintenance will ensure your system functions properly and your batteries live a long, healthy life. On the other hand, if you’re using the deep cycle batteries in a remote area where regular maintenance is not possible, sealed batteries will be a better option. Furthermore, sealed batteries conform to situations with space constraints that require you to store your batteries in unusual orientations or where venting is not possible. Lithium batteries are the cream of the crop. They will will more efficiently store and deliver the renewable energy you have generated, with no maintenance on your part.

Sunlight, temperature, and battery type will influence specific charging times. To get a general idea, you’ll need to calculate amps delivered from your solar panels (total wattage/voltage of your battery). Then you’ll divide the amp hours of your solar battery by amps delivered. For example, if your marine battery system is set up by a 100ah 12v deep cycle battery with three 100 watt solar panels, your system would deliver 25 amps. By dividing 100Ah by 25 amps, you’ll learn it will take four hours for a 300 watt solar panel system to charge a 12v 100ah battery.

The lifespan of a deep cycle battery varies by battery types. Normally, AGM batteries lasts about 4-7 years; Gel batteries lasts about 2-5 years; Flooded Lead Acid batteries lasts 4-8 years, and a high quality Lithium battery can last more than 10 years. The lifespan of a deep cycle battery also effected by battery cycles, maintenance, and the environment in which the battery is kept. For example, a Lead-acid battery’s cycle life can range from 500 to 1200, and a lithium battery can range from 2000 to more than 5000. Besides, a battery kept in a hot environment will experience a shorter lifespan than that in a cooler environment. Thus, for example, the same kind of lithium batteries, but when used as marine batteries and boat batteries, or work for an RV system, the actual service life may be somewhat different depending on the daily usage scenario.

The symptoms of a bad deep cycle battery show when the battery fails to maintain a charge, or shows sluggish performance, or has shorter run times. Or you can tell your battery is bad by finding things like a damaged terminal, bulge or bump in the case, crack or rupture of the plastic, excessive leaking, or discoloration. Terminals that are broken or loose might can cause a short circuit. When a battery short circuits, all the power is unloaded instantly, generating a lot of heat and can potentially cause the battery to explode. Also, cracks, splits, and holes may not cause a battery to stop working, but the battery should be labeled unsafe for safety reasons. If a physical check reveals nothing, try measuring the battery voltage. Make sure it is fully charged before carrying out a voltage check on it, and give it to rest for 3-5 hours. You can use a multimeter to measure your batter’s electrical value. As a well-functioning 12V deep cycle battery is fully charged, its voltage should range from 12.7V to 13.2V. If the voltage reading shows 0, it indicates a short circuit and a dead battery. If the voltage is below 10.5 volts, your battery has to be replaced. If the test reads 12.4 volts or less, but your charger indicates a fully charged battery, it means the 12 volt deep cycle battery is sulfated and will require replacement.

Brava provides high quality deep cycle batteries for solar systems, the Brava battery can be a great option for your RV, marine, and any solar panel system, perfectly meeting the power need of various scenarios. Add the stable, long-lasting, and compact deep cycle lithium RV batteries to your camper, keep your adventure empowered, and stay comfortable and safe on your journey. Upgrading your boat to the reliable deep cycle boat batteries,the AGM, GEL, or Lithium deep cycle marine battery will allow you to enjoy more energy than a traditional flowing liquid battery. Enjoy more fun of being on the water, no need to worry about your deep cycle marine batteries running low after a long day of use.

Use Cases

Because of their different designs, deep cycle and traditional lead-acid batteries work for vastly different scenarios.

• Deep cycle batteries aren’t often found in everyday vehicles, like cars and trucks. Instead, they work to provide a steady supply of a lower amount of power compared to traditional batteries, making them ideal for recreational vehicles, boats, golf carts and electric vehicles, such as medical carts or electric bikes.
• Traditional lead-acid batteries are probably familiar to most drivers, as these are common in many everyday vehicles, like cars, SUVs, trucks and other light-duty vehicles that need short bursts of power to start up the vehicle engine.

CCA vs. RC

When you’re looking into deep cycle batteries and traditional lead-acid batteries, you’ll come across the terms cold cranking amps (CCA) and reserve capacity (RC).

• CCA indicates the number of amps a battery produces in 30 seconds at 0°C (32°F) while maintaining a minimum of 7.2 voltage.
• RC is the number of minutes a battery can produce 25 amps with a minimum of 10.5 voltage.

A lead-acid battery will provide about two times more CCA compared to a deep cycle battery, while a deep cycle battery provides two or three times as much RC as a traditional lead-acid battery.

Starting (sometimes called SLI, for starting, lighting, ignition) batteries are commonly used to start and run engines. Engine starters need a very large starting current for a very short time. Starting batteries have a large number of thin plates for maximum surface area. The plates are composed of a Lead “sponge”, similar in appearance to a very fine foam sponge. This gives a very large surface area, but if deep cycled, this sponge will quickly be consumed and fall to the bottom of the cells. Automotive batteries will generally fail after 30-150 deep cycles if deep cycled, while they may last for thousands of cycles in normal starting use (2-5% discharge).
Deep cycle batteries are designed to be discharged down as much as 80% time after time and have much thicker plates. The major difference between a true deep cycle battery and others is that the plates are SOLID Lead plates – not sponge. This gives less surface area, thus less “instant” power like starting batteries need. Although these can be cycled down to 20% charge, the best lifespan vs cost method is to keep the average cycle at about 50% discharge. Unfortunately, it is often impossible to tell what you are really buying in some of the discount stores or places that specialize in automotive batteries. The golf cart battery is quite popular for small systems and RV’s. The problem is that “golf cart” refers to a size of battery case (commonly called GC-2, or T-105), not the type of construction – so the quality and construction of a golf cart battery can vary considerably – ranging from the cheap off brand with thin plates up to true deep cycle brands, such as Crown, Deka, Trojan, etc. In general, you get what you pay for.

Marine batteriess are usually a “hybrid”, and fall between the starting and deep-cycle batteries, though a few (Rolls-Surrette and Concorde, for example) are true deep cycle. In the hybrid, the plates may be composed of Lead sponge, but it is coarser and heavier than that used in starting batteries. It is often hard to tell what you are getting in a “marine” battery, but most are a hybrid. Starting batteries are usually rated at “CCA”, or cold cranking amps, or “MCA”, Marine cranking amps – the same as “CA”. Any battery with the capacity shown in CA or MCA may or may not be a true deep-cycle battery. It is sometimes hard to tell, as the term deep cycle is often overused – we have even seen the term “deep cycle” used in automotive starting battery advertising. CA and MCA ratings are at 32 degrees F, while CCA is at zero degrees F. Unfortunately, the only positive way to tell with some batteries is to buy one and cut it open – not much of an option.