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.
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|Renogy 12V 100Ah AGM||$$$||Buy|
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- Best Group 27 Deep Cycle Battery
- Cheap Group 27 Deep Cycle Battery
- Best Group 24 Deep Cycle Battery
- Cheap Group 24 Deep Cycle Battery
- Best 100ah Deep Cycle Marine Battery
- Best Group 31 Starting and Deep Cycle Battery
- Best Cheap Group 31 Deep Cycle Battery
- The Buying Guide
- What is best deep cycle battery?
- Battery Maintenance
- Series vs. Parallel Connections
Best Group 27 Deep Cycle Battery
#1 Odyssey 31-PC2150S Heavy Duty Commercial Battery
Odyssey 31-PC2150S at a glance:
- 1150 CCA
- 4-year full replacement warranty
- 70% longer life than conventional deep cycle batteries
- Fast recharging
- Suitable for extreme temperatures
If you are after the top of the range group 27 deep cycle battery, then this unit from Odyssey is just that. A key selling point of this unit is the incredible 1150 Cold Cranking Amps and the ability to cope with extremes of temperature thanks to its high-tech design. You’ll also be treated with excellent charging speeds, up to 10 years of service life, impressive deep discharge recovery, and flexible mounting.
With up to 400 cycles to as low as 80 percent discharge, you get a longer life cycle from this battery than competing brands, backed up with a whopping 4-year full replacement warranty. With recharge speeds of between 4 and 6 hours, you will be able to get this battery fully charged in no time, even with a deep discharge, making it a great option for those needing to maximize battery usage and regular use.
This model is built to be mounted in any manner you need and is super vibration resistant and able to deal with high impact shocks. So if you want a sturdy deep cycle battery that is built to the highest specifications and deal with whatever extremes you throw at it, this battery will not let you down.
Cheap Group 27 Deep Cycle Battery
#2 Universal UB121000-45978 12v 100AH Deep Cycle Battery
Universal UB121000-45978 at a glance
- Spill Proof Construction
- Maintenance Free
- Low discharge rate
- Shock and vibration resistant
- 1 year warranty
This deep cycle battery from Universal Power Group is a reliable choice. Being an AGM battery it can be mounted wherever you need and you can be confident that spillage is impossible thanks to its spill proof construction. It also ticks the essential criteria of being resistant to shocks and vibrations – very necessary if you are going to be using this battery on your marine vessel or RV.
With the power of 100-Ah, this is a good option for the power hungry, and if you want the charge on your deep cycle battery to last as long as it possibly can. I also a great choice if it is going to be in storage as its self-discharge rate is less than 3% per month, this along with being an AGM battery means that this is a very low maintenance option.
To recharge this battery it will take about 10 hours, so ensure you plan for this before you need to use it. Before purchasing this battery also make sure that you check that the specifications are suitable for you, it is on the heavier side weighing 60 pounds and its dimensions measure 12.17 x 6.61 x 9.16 inches – so check where you want to mount it.
Best Group 24 Deep Cycle Battery
#3 Vmaxtanks MR107 12V 85AH Marine Deep Cycle Battery
Vmaxtanks MR107 at a glance
- Charge lasts for 10 hours
- Electrolyte Suspension system
- Heavy duty plates
- Maintenance free
- 50-60% depth of discharge
Vmaxtanks products are renowned for their quality and durability, this is because of the advanced way in which they manufacture their plates. The plates within these deep cycle batteries are made of a strong and unique chemical structure that places them miles ahead of other deep-cycle batteries on the market in terms of the length of time you will be using these for so are a worthwhile investment. Being an AGM battery they are also resistant to shocks and vibrations.
This is a reliable choice if your activities see you out all day long and you need a battery that suits your stamina. This Vmaxtanks battery should keep you going for up to ten hours thanks to its 85-Ah rating, so no need to worry about running out of charge.
This product promises to be 100% maintenance free, so no worries if looking after your batteries isn’t at the top of your to-do list as you will not need to check the electrolyte within this product. It has a 50-60% depth of discharge and can recover well if you allow your battery to reach this depth repeatedly. This is a great choice of deep cycle battery and will be a great companion for between 8-10 years.
Cheap Group 24 Deep Cycle Battery
#4 PowerStar MR107 12V 70AH Marine Deep Cycle Battery
Power Star MR107 at a glance
- Sealed deep-cycle battery
- Lightweight design
- Spill prevention
- Safety features
- 2 year warranty
This great value deep cycle battery from Power Star has everything you need from a deep-cycle battery. It is rated at 12V and has 70 Ah, this translates to at least a day outs running time before you need to recharge it. While it is a good idea to recharge whenever you can so it is ready to use when you need it, it won’t be a catastrophe if you forget to do this as this model can recover well from a deep discharge.
The designers of this deep-cycle battery have cleverly constructed this model to ensure that it delivers maximum performance with ultimate durability and safety considerations. With valve regulation fitted, this battery can be mounted where you need it to be and it won’t spill the electrolyte inside. With hard plastic casing, it is also super durable so can withstand the rough and tumble.
If size and weight is an important consideration for your needs, then you will be pleased to learn that this battery is lightweight, weighing around 52 pounds which is at the lower end of the weight spectrum for deep-cycle batteries. Great if you are going to be using it in smaller boats or RVs. The 2-year warranty also makes this deep-cycle battery a desirable option.
Best 100ah Deep Cycle Marine Battery
#5 Renogy 12V 100Ah Deep Cycle Battery
Renogy Deep Cycle AGM Battery at a glance:
- Wide operating temperatures
- Corrosion resistant alloy
- Mountable in any position
- Maintenance free
- Mounting accessories NOT included
If you haven’t got a massive budget but still want a deep cycle battery that work well across a wide range of temperatures, is able to be mounted however you need it to be, and is both durable and reliable, this a great option. Despite the price you also get a decent 1-year warranty giving you added security that this product really can cope with impact, vibrations and little to no tender love and care and still come out smiling.
No matter where you need to put this battery you won’t have to worry as it can be mounted in any position thanks to its spill proof nature. You’ll also get an impressive life cycle out of this battery without having to worry about maintenance, so no need to top fluids or add water. Even with deep discharge, this battery has great recovery rates, making it a great option for heavy users.
These batteries works well with most consumer electricals, for RV, or as part of a solar setup, so if you are looking to test the water with solar power, the cheap price of this battery makes it a great option to get to grips with the technology. So, although this is a Cheap 100ah Deep Cycle Marine Battery, if you haven’t got much to spend and you’re after at least 100-Ah, this is the battery you need.
Best Group 31 Starting and Deep Cycle Battery
#6 Optima 8052-161 D31M Starting and Deep Cycle Battery
Optima 8052-161 at a glance:
- Staring and deep cycle battery
- 900 cold cranking amps
- Incredible durability with Spiral Cell technology
- Withstand 3 times average no. recharges
- 2 year warranty
If you want the best of the best then look no further than this high-quality deep cycle battery from Optima which will outperform even the Duracell bunny. For the price you are provided with a highly durable battery – this is thanks to the super strong plastic casing and Spiral Cell technology making it 15 times better able to resist vibration than other similar batteries on the market. You can also be sure that this battery can be mounted wherever you want it, in whatever position, and it won’t spill.
This battery is built to last as is able to withstand 3 times the amount of recharges as a normal battery so it will last significantly longer – justifying the higher price, this may just be the more economical choice. It also comes with a 2-year warranty to give you peace of mind.
If you are needing a deep cycle battery for marine use or for your RV, this Optima battery is a great choice. It has a reserve capacity of 155 minutes (higher than most on the market) and can also be used as a starting battery as well as a deep cycle. With 900 cold cranking amps (CCA) it can get you going even in colder weather. For the crème de la crème of deep cycle batteries, this is a great choice.
Best Cheap Group 31 Deep Cycle Battery
#7 Vmaxtanks MR137 AGM Battery
Vmaxtanks MR137 at a glance:
- Long 8 to 10 year lifespan
- Mountable in any position
- Deep discharge
- Durable designed
- Maintenance free
For a superb group 31 battery that won’t break the bank, this Vmaxtanks model is the best battery choice for you. This AGM battery has an advanced electrolyte suspension system ensuring it can be mounted in any position and the heavy duty lead and tin alloy casing means it can also withstand some tough treatment. With maintenance free operation you can use this battery for up to 10 years without having to know much about the vagaries of battery care.
The unique chemical and physical structure of this battery means it is not just durable and highly resistant to vibrations, but also highly reliable in terms of performance. The one down side of this design is the weight so you won’t want this to be a battery you move around too much. Nevertheless, you should still be able to lift it at 75 Lbs if you do need to change its position.
You get great storing power with this battery, making it a great option for trolling motors if you like being out on the water for hours, and it also works great as part of a solar power system providing enough energy for most household appliances. So if you want a great cheap group 31 battery, that doesn’t cost you on longevity or efficiency, you should invest in this battery.
The Buying Guide
Deep cycle batteries are used inhouse 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 maths, 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
- Stove, microwave, coffee pot, etc.
What is 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 degrees 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 amphour 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 freshwater 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.
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.
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 from 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.