Deep Cycle, Dual Purpose and Starting Marine, Vehicle and Solar Batteries

dual purpose exide battery 1Lead acid marine batteries are very important piece of equipment, regardless if you have small boat that can be pulled out on dry land by hands, or you have large vessel suitable for long off-shore fishing trips.

Today, there are several battery types that are used on fishing boats: Lead Acid batteries, Nickel Cadmium batteries, Nickel Metal Hydride batteries, Lithium batteries etc.

Non-lead acid battery types do have their advantages, but so do the lead acid batteries and they are still the most used marine battery type.

Best Deep Cycle, Dual Purpose and Starting Marine Batteries List Table

Following table contains most popular starting, deep cycle and dual purpose marine batteries used for marine applications. Dual purpose batteries are added for the comparison - after all, if they can provide enough current for required period of time, feel free to use them as deep cycle marine batteries. Also, if deep cycle and dual purpose marine batteries can provide enough cranking amps, feel free to use them as cranking batteries. However, cranking batteries can provide large currents easily and when maintained properly, they can last for years.

For more reviews and recommendations, feel free to check links in the table (links open in the new windows - Amazon links).

Model Battery Type Goup Size Cell Type Ah MCA RC Weight (lbs/kg)
Battery Tender BTL35A480C Dual Purpose - LiFePO4 8 480 - 3.75 lbs; ~1.7 kg
Battle Born 100Ah 12V LiFePO4 Battery Deep Cycle 31 LiFePO4 100 - - 29 lbs; 13.2 kg
Exide Edge FP-AGM24DP Dual Purpose 24 AGM 75 930 145 50 lbs; 22.7 kg
Exide XMC-31 Deep Cycle 31 AGM 100 1110 200 68 lbs; 31 kg
Lifeline GPL-31T Deep Cycle 31 AGM 105 750 195 69 lbs;  31.5 kg
Mighty Max ML35-12 Deep Cycle U1 AGM 35 - - 23 lbs; 9.6 kg
Odyssey 31M-PC2150 Dual Purpose 31 AGM 100 1370 205 77.8 lbs; 35.3 kg 
Odyssey 34M-PC1500 Dual Purpose 34 AGM 68 1050 135 49.5 lbs; 22.4 kg
Optima 8027-127 D27M Dual Purpose 27 AGM 66 1000 140 54 lbs; 24.5 kg
Optima 8052-161 D31M Dual Purpose 31 AGM 75 1125 155 61 lbs; 27.6 kg
Optima 8016-103 D34M Dual Purpose 34 AGM 55 870 120 46 lbs; 21 kg
Optima 8006-006 34M Starting/Cranking 34 AGM 50 1000 100 38.4 lbs; 17.4 kg
Trojan SCS150 Deep Cycle 24 Flooded Cell 100 650 150 50 lbs; 22.6 kg
Trojan T31 Deep Cycle 31 AGM 102 720 177 69 lbs; 31.5 kg
UPG UB121000 Deep Cycle 27 AGM 100 - - 64 lbs; 29 kg
VMAXTANKS V30-800 Deep Cycle - AGM 30 350 55 22 lbs; 10 kg
VMAXTANKS V35-857 Deep Cycle U1 AGM 35 390 75 25 lbs; 11.3 kg
VMAXTANKS MR96-60 Deep Cycle 22NF AGM 60 600 120 43 lbs; 19.5 kg
VMAXTANKS MR107-85 Deep Cycle 24 AGM 85 700 160 55 lbs; 24.9 kg
VMAXTANKS SLR125 Deep Cycle 31 AGM 125 - 260 75 lbs; 34 kg
VMAXTANKS MR127-100 Deep Cycle 27 AGM 100 800 200 68 lbs; 30.8 kg
VMAXTANKS MR137-120 Deep Cycle 31 AGM 120 900 230 75 lbs; 34 kg
VMAXTANKS SLR155 Deep Cycle - AGM 155 - 350 90 lbs; 40.8 kg
VMAXTANKS MR197-200 Deep Cycle 4D AGM 200 1400 560 112 lbs; 50.7 kg
VMAXTANKS V6-225 Deep Cycle GC2 (6 Volts) AGM 225 - 500 72 lbs, 32.6 kg

Marine Lead Acid Batteries

vmaxtanks slr125Marine lead acid batteries are strong, sturdy and reliable type of batteries that are mostly used in fixed installations and are used as starter batteries, trolling batteries etc.

They have the same chemistry as car batteries and they are based on lead (hence the first part of their name) and its compounds and sulfuric acid (hence the second part of the name).

Main difference between these batteries is their electrolyte - basically, there are flooded (wet) lead acid batteries, gel cell batteries and absorbed glass mat (AGM) batteries.

Flooded (wet) lead acid batteries use liquid electrolyte - it is important to keep these batteries in upright position and to prevent electrolyte from leaking. These batteries must be monitored and if needed, distilled water added when electrolyte levels fall down bellow certain level. Since during operation flammable hydrogen is released, they must be kept in well ventilated area.

Gel Cell batteries use electrolyte in the form of gel - diluted sulfuric acid is mixed with fumed silica to create gel which is placed between battery plates.

Absorbed Glass Mat (AGM) batteries use electrolyte that is held in the glass mats made out of woven, very thin glass fibers.

Both gel cell and AGM batteries are often made as valve-regulated lead–acid (VRLA) batteries - safety valve inside battery opens at certain pressure (usually at 2 psi - 0.14 atm) and let oxygen flow from positive plate to negative plate to recombine with hydrogen and create water - no need to add any water during their operation. Such Sealed Lead Acid (SLA) batteries are maintenance free batteries and are used more and more on fishing boats.

Lead acid batteries lose capacity rapidly if discharged using high currents, but they are pretty immune to memory effect - they can be charged regardless of their initial discharge state, since battery will not 'remember' its previous discharged level. They are very cheap, when compared with other battery types. But, they are rather heavy in terms of energy-to-weight and energy-to-volume ratio.

Typical marine deep cycle lead acid battery has capacity of around 20-30 Wh/kg when discharged in less than one hour (even less when discharged to 20% of capacity in less than 10 minutes) or 30-40 Wh/kg when discharged slowly, for example in period of 20 hours. Actually, when giving capacity, manufacturers usually provide capacity information when battery is discharged slowly for period of 20 hours, but they also provide tables about battery characteristics when battery is discharged at different currents, voltages and temperatures.

marine batteries 3Since lead batteries easily tolerate high surge currents, more and more deep cycle batteries are used as starter batteries too, or as power source for fixed or portable power centers.

Due to their weight, these batteries are often positioned low in the boat, to lower the center of gravity and increase the stability of the boat.

General voltage ranges per cell are:

- at full charge: 2.10 V
- at full discharge: 1.95 V
- loaded at full discharge: 1.75 V

One of the advantages of lead acid batteries is that they can stay connected to chargers all the time (again: no memory effect and in simple instalations these batteries can act as voltage regulators preventing voltage surges - not recommended for their longevity, but ...) - continuous (float) charging voltages are:

- 2.23 V for gel cell batteries
- 2.25 V for AGM batteries
- 2.32 V for flooded (wet) batteries

It must be noted that these voltages are given at 20 °C (68 °F), and must be adjusted by −0.0235 V/°C for temperature changes (for 12V (6 cells) batteries). Also, float voltage recommendations vary slightly among manufacturers - this float voltage is critical for longevity since too low or too high float voltage can significantly shorten life of the battery.

Voltages required for daily charging, equalization charging and gassing threshold depend on temperature and vary among manufacturers, but generally they are:

- daily charging voltage: 2.37–2.4 V
- equalization charging voltage: 2.5 V for no more than 60-120 minutes (wet cells - be sure to open the cells, monitor level of electrolyte, add distilled water if needed, monitor cells temperature!)
- gassing threshold voltage: 2.4 V

Even so, lead acid batteries are IMHO the best choice for boats where additional weight will NOT be a problem.

These batteries are relatively cheap and those newer deep-cycle low-discharge high-power (starting) sealed batteries can last for years.

One of the best things about lead acid batteries is that they are charged using 'voltage' chargers and most of the other types of batteries are charged using 'current' chargers. Hence, lead acid batteries can be connected in parallel and series as one needs in order to achieve higher capacities and/or voltages. However, great care and planning must be taken when doing something like that:

- connecting batteries in parallel one creates battery pack of the same voltage but higher capacity. Due to slight difference in voltages between flooded (wet) cells, gel cells and AGM cells, it is important NOT to mix those types of batteries. In fact, it is recommended to use THE SAME type of batteries, the same model with the exactly the same capacity from the same manufacturer, preferably from the same batch! And the best solution is to obtain single battery of the required capacity.

- connecting batteries in series one creates battery pack of the same capacity, but higher voltage. Batteries of the same capacity must be used and even then batteries should NOT be discharged less than 20% of their capacity due to danger of cell reversals. Again, try to use the same type of batteries, the same model with the exactly the same capacity from the same manufacturer, preferably from the same batch! And the best solution is to obtain single battery of the required voltage.

I know that this sounds little bit paranoid, but these things are not toys, they can cause fires, damage and even harm people. If you are not sure what to do, it is better to find professionals - just explain them what you want or need and they will either find a solution or find someone who can find you a solution. Such services do cost money, but in the long run they are worth it - or you would like to jump off the fishing boat due to fire, 20 miles off the shore, while your chum and baits are in the water and sharks might be around...? :o)

For more on marine batteries, their types, their use etc. check these guides:

- Dual Purpose Marine Batteries

- Trolling Motor Battery - The Best Deep Cycle Marine Batteries

- Nickel Cadmium, Nickel Metal Hydride and Lithium Batteries

- Choose the Best Fish Finder Battery

- Battery Group Sizes and Terminology

- AWG to mm2 Conversion Calculator and Chart

- How to Charge Marine Battery

- Selecting the Best Golf Cart Battery

- Best 18650 Batteries and Chargers

- Guide to LR44, AG13, LR1154, SR44, 303, 357 Batteries

- Marine Battery Boxes, Trays And Mounting Kits

- Marine Battery Monitors

- Electric Trolling Motors

- Marine Battery Chargers And Controllers

- Marine Solar Panels

- Marine Wind Turbine Generators

- Marine Power Generators

- Manual Power Generators

- Best RV Deep Cycle Battery

- Best 100 Ah AGM Deep Cycle Marine Battery

Our latest reviews and recommendations:

vmaxtanks v6 225 mVMAXTANKS 6 Volt 225Ah AGM Battery is one of the best buy deep cycle AGM batteries, suitable for use as solar or wind turbine battery, RV battery, golf cart battery, electric trolling battery etc. It features long Float Service Life (up to 8 to 10 years), but thanks to heavy duty lead tin alloy, it is very durable battery with long service life in either float or cyclic applications, even after repeated over discharges - which should be nonetheless avoided as much as possible, of course.

battle born battery lifepo4 100ah 12v mBattle Born 100 Ah 12 Volt LiFePO4 Deep Cycle Battery is 'drop-in' replacement for lead-acid deep cycle batteries in marine, RV, golf cart and other applications where lightweight and reliable battery is required. Due to the LiFePO4 technology and protective electronics, battery also feature high number (3000-5000) charge-discharge cycles, high/low voltage protection, short-circuit protection, temperature protection, automatic cell balancing and can be even charged with battery chargers designed for lead acid batteries.

But, it also costs more than similar 100Ah 12V SLA AGM batteries.

optima 34m bluetop mOptima 34M BlueTop Marine Starting Battery is very popular SLA AGM marine battery commonly used as the starting/cranking battery in smaller fishing boats. Although it can be used as dual purpose, or even as deep cycle battery (not recommended, of course), it is best used in applications, which it was designed for - as reliable, relatively lightweight, but strong cranking battery.

mighty max ml35 12 battery mMighty Max ML35-12 is a 12V 35Ah deep cycle, sealed lead acid (SLA) AGM battery, suitable for use in a wide variety of applications like power sports, solar, electric vehicles, cranking battery, golf carts, lawn and garden tools, security etc.

Although it is designated as 'deep cycle' battery, it is often used as dual purpose battery on small boats, and in lighter vehicles with internal combustion engines.

odyssey 34m pc1500 mOdyssey 34M-PC1500 Trolling Thunder Marine Dual Purpose Battery is BCI Group Size 34 battery. It is truly dual purpose battery combining good starting power and deep cycling capabilities. Odyssey 34M-PC1500 Marine Dual Purpose Battery is very similar to Odyssey 34-PC1500, Odyssey 34R-PC1500, Odyssey 34/78-PC1500 and Odyssey 78-PC1500 batteries. All these batteries are very similar and are suitable for various roles, and can be used as starting/cranking battery, trolling motor battery, electric vehicle battery etc.

upg ub121000 1mUniversal Power Group UB121000 Deep Cycle AGM Battery is very popular BCI Group Size 27 marine battery. It is suitable for deep discharge applications, like trolling motor battery, RV battery, UPS batteries, and similar. It can be mounted in any position, it is spill-proof, and available at affordable price.

odyssey 31m pc2150 1mOdyssey 31M-PC2150 Marine Dual Purpose Battery is BCI Group Size 31 battery which combines good starting power and deep cycling capabilities. Odyssey 31M-PC2150 Marine Dual Purpose Battery is very similar to Odyssey 31-PC2150 Heavy Duty Commercial Battery, and they are both suitable for various roles, including trolling motor battery, cranking battery and similar.

lithium btl09a120c tlithium btl35a480c tBattery Tender 12V Lithium Iron Phosphate Batteries is group of several lithium, dual purpose, batteries. They are lightweight batteries, have large discharge currents, large number of charging cycles and have many other benefits when compared with similar lead-acid batteries. On the other hand, they must be charged with proper chargers and they cost more than corresponding lead-acid batteries.

exide edge fp agm24dp 1mExide Edge FP-AGM24DP Flat Plate AGM Sealed Dual Purpose Marine Battery is BCI group 24 marine and RV battery. It combines very good starting power with deep cycle capabilities, making it suitable for various roles, including trolling motor battery, cranking battery and similar. It comes with dual terminals, carrying handle and more than acceptable price.

exide mc 31 mexide xmc 31 mExide MC-31 and XMC-31 MEGACYCLE AGM-200 Sealed Maintenance Free (AGM) Marine Batteries are two very similar, dual purpose marine batteries. Being lead acid AGM batteries, they are rather heavy when compared with the similar lithium marine batteries, but they are much cheaper, have very good vibration resistance and are generally very robust and reliable.

gen 4 bank 40a 150NOCO Genius Waterproof Smart On-Board Battery Chargers are group of lead acid battery chargers. They come in several versions regarding charging current (4A and 10A) and number of battery banks that can be charged at the same time (1, 2, 3, or 4 battery banks). Also, they have very important safety features like reverse polarity protection, sparks prevention, prevention of overcharging, overcurrent, open-circuits, short-circuits and overheating.

noco 12v lithium jump starters 1m

NOCO Genius Boost 12V UltraSafe Lithium Jump Starters is a group of several jump starters powered by lithium batteries. They are: Sport GB20 400 Amp, Plus GB40 1000 Amp, HD GB70 2000 Amp and Pro GB150 4000 Amp. While smallest Sport GB20 is strong enough to start motors of smaller boats, yachts, cars and similar, largest Pro GB150 4000 Amp is capable of starting even the largest car, truck, boat and yacht motors. Nonetheless, be sure to get jump starter according to your actuall need or perhaps slightly stronger. 'Stronger jump starter' also means 'more expensive', but this is the type of equipment that one should hopefully never use - after first use, you will forget initial costs.

optima redtop yellowtop bluetop 1mOptima batteries are very popular lead acid automotive and vehicle batteries. Depending on their intended purpose, they come in three versions, easily distinguished by their color: RedTop, YellowTop and BlueTop.

optima d34m d27m d31m 1m

Optima D34M, D27M, D31M BlueTop Dual Purpose Marine Batteries are three models of very popular Optima AGM batteries. They are 'true' dual purpose batteries suitable as marine cranking batteries and deep cycle marine batteries. And they come at affordable price.

vmaxtanks batteries 1m

VMAXTANKS Batteries V30-800, V35-857, MR96, MR107, SLR125, MR137, SLR155 and MR197 are the most common VMAXTANKS batteries used in marine and similar applications. Although they are defined as 'deep cycle' batteries, they can be used as starting batteries, too, just one must be aware of their limitations.

vmaxtanks bc1220a 1mVMAXTANKS 12V Smart AGM, Gel Cell and Flooded Lead-Acid Battery Chargers is series of microprocessor controlled smart battery chargers. They charge, maintain and if required, recondition lead-acid battery using several charging stages. They include several safety features to prevent overcharging, short circuits and other possible errors and problems.

schumacher ssc 1000a 1mSchumacher SSC-1000A Ship 'N' Shore SpeedCharge 2/6/10 Amp Battery Charger and Maintainer is very popular 12V battery charger and maintainer for flooded, gel-cell and AGM lead acid batteries. It is fully automatic, microprocessor controlled unit, having three charging rates, built-in battery tester, desulphation mode and many other features that make him suitable for charging marine, car and many other lead acid batteries.

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