Best Deep Cycle Battery

Boat batteries serve one of two purposes. Starting batteries produce short, powerful bursts of energy to start the engine, run for about 15 seconds and then the alternator takes over. This function is the same as an automobile battery. The deep cycle battery is used for larger amounts of energy that discharges deeply and repeatedly recharges, so it is best used for the other electric needs of the boat.

Top 5 Best Deep Cycle Battery

  • Type: Deep Cycle
    Voltage: 12V
    Capacity: 155Ah
    Group Size: 30H
  • Type: Deep Cycle
    Voltage: 12V
    Capacity: 125Ah
    Group Size: 31
  • Type: Deep Cycle
    Voltage: 12V
    Capacity: 100Ah
    Group Size: 27
  • Type: Dual Purpose
    Voltage: 12V
    Capacity: 55Ah
    Group Size: 34
    CCA 750
  • Type: Deep Cycle
    Voltage: 12V
    Capacity: 110Ah
    Group Size: 33
    CCA 1420


Editor’s Rating


  • Custom military grade plates
  • Life span of 10 to 12 years
  • Ideal solar storage battery

This is a deep cycle AGM battery. The plates of this battery are made of custom military grade. The VMAX SLR155 battery has superior performance capacity and it has life span of 10 to 12 years. It is one of the most reliable and high performing rechargeable batteries, with power of 155 Ah. This battery is specially designed for capability of 99% recombination and it doesn’t release any toxic fumes or gases unlike many other batteries. The VMAX SLR155 battery is 100% maintenance free and is very reliable and safe for indoor use. It is an ideal choice for solar storage. This battery weighs 92 pounds and it costs around $310, pretty expensive but a good high budget choice if one desires long life span.


Editor’s Rating


  • Recombination capability of 99%
  • Doesn’t emit any gases or fumes
  • Safe for indoor use

This is a 12 volt rechargeable deep cycle AGM battery with power of 125 Ah. It is an ideal choice for indoor use appliances like PV solar panels, inverters and turbines. This battery is very reliable and gives high performance. The Vmaxslr125 battery is designed for recombination capability of 99% and it doesn’t emit any gases or fumes, which make it extremely safe for indoor use. The life span of this battery is 8 to 10 years. The Vmaxslr125 battery weighs 75 pounds and costs nearly $260, a good deal for that much performance and life.

Universal UB121000

Editor’s Rating


  • Completely spill proof
  • Best choice for solar wind panels
  • High performance

This is a valve regulated lead acid 12 volt AGM battery with power of 100Ah. The absorbed glass mat technology of the battery makes it capable for delivering high performance and the valve regulated technology makes the battery completely spill proof and compatible for mounting in any position. This battery is best choice for solar wind panels. Other than solar panel, this battery is also compatible for motorcycles, golf carts, electric vehicles and many more. This battery weighs 60 pounds.

Optima 8014-045-FFP

Editor’s Rating


  • Deep charge and discharge
  • Great starting power
  • Works even in bad weather conditions
  • 15 times more vibration resistant

This is a 12 volt deep cycle battery, weighing 43 pounds. The cold cranking amps of this battery is 750 and it is capable of taking deep charge and discharge. This battery can accept recharge three times more than other batteries of this type. The Optima 8014-045-FFP YellowTop battery has 120 minutes of reserve capacity when used constantly and has a great starting power even in extremely bad weather conditions. This battery is 15 times more vibration resistant and has good durability. The cost of this battery is nearly $200, which a good choice for average budget. It is available in group 38 or 78.

Chrome Battery 12V 110AH SLA

Editor’s Rating


  • Lead and calcium alloy plates
  • T8 type of terminals
  • Spill and leak proof

This is a deep cycle sealed lead acid 12 volt AGM battery. This battery has lead and calcium alloy plates and the AGM technology makes the battery completely maintenance free. This battery is one of the most reliable rechargeable batteries available in the market and it has T8 type of terminals that makes it deliver high performance. The 110AH 12V DC Chrome battery is spill and leak proof, compatible for any mounting position. The highly compressed cell and fiberglass separator technology makes the battery resistant to heavy vibrations and more performance.

The Buying Guide

Deep cycle batteries are used in house battery banks maintaining power when there is no other source available. Deep cycle batteries are manufactured on the same basic principle as any battery: a resilient plastic case enclosing a grid that is immersed in electrolyte and conducts electricity providing power for various applications.

Deep cycle batteries have thicker lead plates than its starting battery counterpart. The thickness contributes significantly to the lifespan of the battery. Its design delivers a steady amount of power over a long period without failure. The average deep cycle can be discharged up to 80% repeatedly. The denser active material ratio provides better cycling capacity.

  • Cycling is one battery discharge and recharge of any depth.
  • The depth of discharge is the amount of discharge compared to the full capacity.
  • Using simple math, if a battery level reads at 40% depth, it means that there is 60% state of charge left.

The build, design, and reliability make it perfect for marine use when you are out enjoying the water away from shoreline power sources. You can stop and enjoy the day without worries.

This particular battery is well suited for a long list of amenities that improve your boating experience:

  • Air conditioning and heating system
  • Interior and running lights
  • Larger capacity refrigerator/freezer
  • Music systems with multiple speakers
  • Computer, GPS, cell phones
  • Fish finder, depth finder
  • Hydraulics
  • Stove, microwave, coffee pot, etc.

Factors to Consider When Choosing the Best Deep Cycle Battery

Amp Hour Capacity: The first thing to consider when choosing the best deep cycle battery for your needs is the battery ratings. The Battery Council International (BCI) has established industry standards for rating batteries.

  • Ampere Hour Rating (Ah): This is the number of amps that a battery can deliver for a 20-hour period. The test is also referred to as the 20-hour rate. The larger the ampere-hour rating, the more power the battery can deliver over time.
  • Marine Cranking Amps (MCA): This is the number of amps a battery can deliver at 32 degrees Fahrenheit for 30 seconds and maintain a voltage of 1.2 volts per cell. This differs from cold crank amps, which are measured at 0 degrees Fahrenheit. The MCA is not as important for deep cycle applications as it is for starter needs.
  • Reserve Capacity (RC): This is the time measured in minutes for which a battery will deliver 25 amperes at 80 degree Fahrenheit. This represents the time that the battery will continue to operate essential accessories in the event of alternator or generator failure or when the key is off.

One would then need to calculate the amp hour capacity battery needed. To start, compute the hour draw of the accessories on the boat. Take an inventory of all the electrical equipment on the boat with a 12-volt amp draw. For example, a fresh water pump has a 4.0 amp draw. Add up the accessories and multiply by 20 and this would give you an approximation of your boat’s requirement. It is also suggested that the battery should be at least 20% of the above requirement.

Battery Chemicals: All batteries have the same basic structure: Grids and separators in a cell with the cells connected all encased in a durable polyethylene case. There are some differences after that.

  • The flooded battery (also called wet battery) uses a reservoir of electrolyte (a mixture of liquid sulfuric acid and water) to act as a pathway between plates. When the battery charges, explosive gasses are released requiring ventilation. The flooded battery requires a frequent refill of distilled water. They must be installed in an upright position and are unable to tolerate vibration. These are the least expensive of the forms.
  • Gel batteries, sealed, valve regulated (SVR) gelled electrolyte batteries offer advantages over regularly flooded batteries. The electrolyte in the gel battery is mixed with silica making it quite viscous to resist leaking. The gasses that are produced during charging are recombined to create water that inhibits drying. They only self-discharge at 3% per month and require careful regulation to prevent overcharging.
  • AGM or Absorbed Glass Mat batteries feature glass mat separators saturated with acid electrolyte between the positive and negative plates. The pressure valves allow oxygen produced on the positive plate to migrate to the negative plate and recombine with the hydrogen producing water. The batteries have better shock and vibration protection than wet or gel batteries and are virtually maintenance free.

Battery Maintenance: This is as important as anything when choosing a battery. The Flooded (Wet) Lead Acid batteries require the most maintenance of any type of battery. All of the battery information is based on proper care. Regardless of the manufacturer or the specifications listed, an abused battery is never a good battery.

  • All batteries require the top be cleaned and remain free from dirt and debris. Allowing corrosion to build up on the terminals will impede the passing of power to accessories.
  • Charging is an especially important part of the maintenance free batteries. It is important to follow the correct number of hours for charging, and it must be fully charged immediately especially after storage or if you have not taken the boat out for a while.
  • Do a routine check for bulges, cracks. Bulges and cracks are signals that there may be a problem with the alternator, or the battery is not being properly charged.
  • It is crucially important your battery is put on a trickle charge for the winter. Many batteries cannot handle a deep discharge and may need to be replaced.
  • Replacing one chemical battery for another will deter battery life
  • Shallow discharges mean a longer battery life and an 80% discharge is the maximum for deep cycle batteries
  • Replacing one battery at a time seems like an inexpensive alternative, but the old battery will drain newer batteries down to its level
  • Keep batteries in an acid-proof storage box secured with tie downs to resist vibrations. The extreme vibrations from the boat will decrease lifespan
  • Maintain fluid levels in wet cell batteries
  • Corrosion resistant terminals still need attention and will benefit by light lubrication

Series vs. Parallel Connections

  • Series connection means that two batteries of like voltage and Ah capacity are connected to increase the voltage of the battery bank. The positive terminal of the first battery is connected to the negative terminal of the second and vice versa until the desired voltage is reached. The sum of all the battery voltages added is the final voltage while the Ah, cranking performance and reserve capacity remain the same.
  • Parallel Connection means that two batteries of like voltages and capacities are connected to increase the capacity of the battery bank. The positive terminals of all batteries are all connected together or to a common conductor and all negative terminals are connected likewise. The final voltage remains the same while the capacity of the bank is the sum of all the capacities of the connected batteries. Opposite the series connections the Ah, cranking performance and reserve capacity increases while the voltage remains the same.

Like so many other options with batteries, you should consider your needs when determining which connection will work best for your needs.

Choosing the best deep cycle battery is not as simple as running out to the local big box and grabbing something off the shelf and hook it up to your boat. The options for batteries are numerous and taking the time to determine your needs and balancing your needs with your budget is critical to determining which battery is best for you. Taking the time to wade through the lake of information will be worth the effort.

Best Deep Cycle Battery

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Last modified:November 6, 2015


  1. Your recommended deep cycle batteries are each 35Ah. Most of the online guides I rad say I should be getting at least 100Ah. What am I missing?