Odyssey 31M-PC2150 AGM Marine Dual Purpose Battery Review and Recommendation

Odyssey 31M-PC2150 is BCI group 31 battery, designed as dual purpose battery. As starting battery it can easily provide 1000+ CCAs and as deep cycle battery it comes with 205 min RC rating.

Odyssey 31M-PC2150 is AGM SLA battery, featuring increased resistance to vibrations, spill-proof design, two types of terminals, can operate in any position etc.

It is one of the heaviest group 31 batteries on the market and far from being cheap, but it is one of the best batteries in its class (if not the best) and worth every (euro)cent.

odyssey 31m pc2150st m battery

Odyssey 31M-PC2150 Features and Specifications

Technical specifications of the Odyssey 31M-PC2150 battery are given in the following table:

Nominal Voltage CCA HCA MCA PHCA 20h Capacity 10h Capacity RC Terminals
12 V 1150 1545 1370 2150 100 Ah 92 Ah 205 min SAE and 3/8” Stud (Pos.); 5/16” Stud (Neg.)

Its physical dimensions are 13 x 6.8 x 9.41 inches (330.2 x 172.7 x 239.0 mm) and it weighs 77.8 lbs (35.3 kg).

Odyssey 31M-PC2150 is Absorbed Glass Mat (AGM) battery - it features non-spillable electrolyte and it can operate in any position.

Like typical marine battery, Odyssey 31M-CP2150 features double terminals: SAE and 3/8” Stud (positive), 5/16” Stud (negative).

Odyssey 31M-PC2150 has very low self-discharge rate - a fully charged battery can be stored for up to two years at 77ºF (25ºC) or until its voltage drops below 12V (whatever happens first). Self-discharge rate depends on the storage temperature and is given in the following table:

Storage Temperature 41°F (5°C) 59°F (15°C) 77°F (25°C) 95°F (35°C) 113°F (45°C)
Storage Time 48 months 36 months 24 months 12 months 6 months

So, after 24 months at 77°F (25°C), fully charged battery voltage will drop down to around 12V and that battery must be charged again.

When the battery leaves the factory, it is shipped in the fully charge state and its voltage is 12.84V (or slightly higher) indicating 100% SOC (state of charge). Over time, the voltage drops slowly - if the battery OCV (Open Circuit Voltage) is over 12.65V, battery can be installed and used as fully charged.

If the voltage is 12V or less (~35% SOC), the battery should be considered discharged and it must be charged prior first use.

OCV depends on the SOC and that dependency is given in the following table:

SOC 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
OCV 11.70 V ~11.82 V ~11.95 V ~12.08 V ~12.20 ~12.32 V ~12.46 V ~12.58 V ~12.70 >12.84 V

Knowing OCV is important in avoiding deep discharge conditions and prolonging the battery operating life.

Odyssey 31-PC2150 Dual Purpose Battery Versions

Odyssey 31-PC2150 is manufactured in several versions, with each version being optimized for specific use.

odyssey 31 pc2150 versions

Main difference between they batteries are type and orientation of battery terminals:

- Odyssey 31-PC2150 comes in two versions, having 3/8" Stud or SAE battery terminals. Often, these batteries are labeled as 'Odyssey 31-PC2150T Heavy Duty Commercial Battery' or 'Odyssey 31-PC2150S Heavy Duty Commercial Battery' and indeed, they are batteries for heavy duty commercial use.

- Odyssey 31M-PC2150 features SAE and 3/8” Stud (positive) 5/16” Stud (negative) battery terminals. This battery is often labeled as 'Odyssey 31M-PC2150ST-M TROLLING Thunder Marine Dual Purpose Battery' since it can be used as both starting marine battery, but also as deep cycle marine battery, including trolling fishing.

- Odyssey 31R-PC2150 is just like Odyssey 31-PC2150, it just have terminal polarities reversed left and right.

Note: all versions of 31-PC2150 batteries have the same electrical performances (capacity, RC, CCA, MCA etc).

Extreme Deep Discharge Recovery

Odyssey 31M-PC2150 battery can be recovered from deep discharge state (down to almost 0% of remaining charge), however, such events should be avoided as much as possible.

If something like that happen to the new battery, one should charge the battery to at least 13.5V, preferably to 14.4V, allowing the battery to recover at least 97% of its nominal capacity.

Again, if possible avoid such deep discharge events.

Odyssey 31M-PC2150 AGM as Starting Battery

Battery's plates are made using 99.99% pure lead, and they are densely packed providing good starting power.

New, fully charged battery can provide 2150 Amps for 5 seconds - this is its PHCA (Pulse Hot Cranking Amps) rating, thus '2150' is part of the battery's label.

HCA (Hot Cranking Amps; 80°F, 27°C) rating is 1545 Amps, MCA (Marine Cranking Amps; 32°F, 0°C) rating is 1370 Amps and IMHO, the most important CCA (Cold Cranking Amps; 0°F, -18°C) rating is 1150 Amps.

Odyssey 31M-PC2150 battery provides 1000+ CCA and it is more than strong enough for most automotive and marine cranking applications and highly recommended model for dual purpose applications as part of single battery (or single battery pack) electrical systems commonly found in the cars, RVs, boats, yachts etc. where both good starting power and deep cycle performances are required.

odyssey 31m pc2150st m battery 2

Extreme Cold Temperature Starting Performances

One of the important features of Odyssey 31M-PC2150 battery (and other 21-PC2150 batteries) is very good performance during extremely cold temperatures.

As said before, its CCA (Cold Cranking Amps; 0°F, -18°C) rating is 1150 Amps and as temperature is increased, so are its cranking amps (maximum current for 30 seconds, without the voltage dropping below 7.2 V).

However, Odyssey 31M-PC2150 is designed to operate safely down to -40°F (-40°C) and that is rather cold, to say the least.

Under these temperatures (-40°F, -40°C!), Odyssey 31M-PC2150 is able to provide 550 cranking amps for 30 seconds, without its voltage dropping below 7.2 V - actually, according to the manufacturer, brand new, fully charged and cooled down to -40°F (-40°C) Odyssey 31M-PC2150 battery can provide 550 Amps for ~34 seconds.

Such cold temperature tolerances and performances mean that during the winter battery can be left on the boat, yacht, RV or at any similar location without safety or reliability issues. If you do expect local temperatures to be lower than -40°F, it is recommended to remove the battery during such extreme cold period and store it in the warm(er) area - important note for Alaska, Canada or Siberia! :)

Odyssey 31M-PC2150 AGM as Deep Cycle Marine Battery

Although battery's plates are relatively thin (to provide high currents), they are designed to withstand many charging-discharging cycles. For example, the battery can withstand around 400 charge-discharge cycles down to 80% of maximum discharge (80% DoD - Depth of Discharge, 20% charge left).

However, avoiding really deep discharges can significantly prolong the battery's operating life, as shown in the following table:

DoD% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%
Number of Cycles ~6000 ~2200 ~1300 ~900 ~650 ~550 ~470 400 ~380 ~320

Note: battery is considered good as long as its native 20h capacity is more than 80% of the 20h capacity of the new battery. That means that when 31M-PC2150 battery 20h capacity drops down to 80 Ah or less, the battery is not considered to be good and should be properly recycled!

Although nominal capacity of the battery is 100 Ah, when the fully charged battery is being discharged down to 10.05 V (note: 10.05 V, not the 10.5 V) using constant current at 77°F (25°C), its capacity depends on the current and discharge time and are given in the following table:

Time Watts (W) Amps (A) Capacity (Ah) Energy (Wh)
2 min 7025 678.5 22.4 231.8
5 min 4740 438.5  36.4  393.4
10 min 3176  285.9  47.7  530.4
15 min 2428  215.5  53.9  607.0
20 min 1980  174.1  58.0  659.2 
30 min 1460  127.0  63.5  730.0 
45 min 1059  91.2  68.4  793.9 
1 hr 835  71.5  71.5  835.2 
2 hr 461  39.0  78.0  922.2 
3 hr 322  27.1  81.4  966.8 
4 hr 249  20.9  83.8  996.8 
5 hr 204  17.1  85.6  1020.0 
8 hr 134 11.2  89.7  1070.4 
10 hr 110  9.2  91.9  1095.9 
20 hr 60  5.0  100.3  1191.9 

It is normal for all lead-acid batteries to lose capacity as they are being discharged using strong currents and Odyssey 31M-PC2150 is no exception. However, as the discharging current increases, its capacity drops, but it is still one of the best performers in its class.

If you have 50-60 pounds electric trolling motor which draws some 50-60 Amps at maximum power, in the worst case scenario, one can expect one hour of operation (plus some 10-15 minutes for safety). And since many fishermen don't use trolling motors at full power when fishing, one can expect 2-4 hours of operation on half a throttle of such electric trolling motor (time depends on the battery condition, weather conditions, actual trolling pace, etc).

When charging 31-PC2150 battery used for cycling applications, it is important to use battery chargers that can deliver at least 0.4C strong currents in the bulk charge mode and that can charge the battery up to 14.7 V.

Odyssey 31M-PC2150 vs. Other Group 31 Batteries

 battleborn lithium 300pxexide xmc 31 modyssey 31m pc2150st m battery moptima 8052 161 d31m m

  Following table lists the most popular BCI group 31 batteries, with their most important features:

Model Battery Type Goup Size Cell Type Ah MCA RC Weight (lbs/kg)
Battle Born 100Ah 12V LiFePO4 Battery Deep Cycle 31 LiFePO4 100 - - 29 lbs; 13.2 kg
Exide XMC-31 Dual Purpose 31 AGM 100 1110 200 68 lbs; 31 kg
Lifeline GPL-31T Deep Cycle 31 AGM 105 750 195 69 lbs;  31.5 kg
Odyssey 31M-PC2150 Dual Purpose 31 AGM 100 1370 205 77.8 lbs; 35.3 kg 
Optima 8052-161 D31M Dual Purpose 31 AGM 75 1125 155 59.8 lbs; 27.1 kg
Trojan T31 Deep Cycle 31 AGM 102 720 177 69 lbs; 31.5 kg
VMAXTANKS SLR125 Deep Cycle 31 AGM 125 - 260 75 lbs; 34 kg
VMAXTANKS MR137-120 Deep Cycle 31 AGM 120 900 230 75 lbs; 34 kg

Note: Amazon affiliate links in the table open in the new windows, feel free to check them out. Also, table lists MCA values and not CCA values of the batteries.

All of the batteries in the table are lead-acid AGM batteries except Battle Born 100Ah LiFePO4 deep cycle battery, which is excellent deep cycle battery designed for various application, except starting applications (it can deliver 100 Amps continuously, and 200 Amps for 30 seconds).

Also, it is very lightweight battery, being almost 3x lighter than Odyssey 31M-PC2150 battery. But, Battle Born 100Ah LiFePO4 deep cycle battery is also very expensive battery.

When 31-PC2150 batteries are compared with other group 31 AGM batteries, one can conclude:

- group 31 AGM batteries are heavy, and the 31-PC2150 is one of the heaviest in this class,

- high quality deep cycle group 31 batteries have somewhat better 20h capacity and RC rating than 31-PC2150 battery,

- common deep cycle group 31 AGM batteries have capacity and RC rating similar to the 31-PC2150 dual purpose battery.

- other dual purpose group 31 AGM batteries are lighter and have lower CCA/MCA rating than the 31-PC2150 battery.

Personally, in this group only Exide XMC-31 come close to the 31-PC2150 battery. However, also note that Exide XMC-31 is almost 10 pounds lighter battery.

If you need good 31 group AGM battery and don't have weight issues, go for Odyssey 31M-PC2150 battery.

Odyssey 31M-PC2150 vs. Other 1000+ CCA Batteries

acdelco 49agm battery modyssey pc1800 ft battery modyssey pc2250 battery mvmaxtanks mr197 battery m

To be able to provide 1000+ CCAs is very tough requirement for any type of marine or automotive battery.

Many batteries can provide 1000+ MCAs and especially 1000+ HCAs, but as the temperature drops, so does the cranking amps.

Following table lists marine/automotive batteries which are able to provide at least 900 CCAs:

Model Battery Type Goup Size Ah CCA RC Weight (lbs/kg)
ACDelco 49AGM Dual Purpose 49 95 900 160 -
Exide XMC-31 Dual Purpose 31 100 925 200 68 lbs; 31 kg
Odyssey 31M-PC2150ST-M Dual Purpose 31 100 1150 205 77.8 lbs; 35.3 kg 
Odyssey PC1800-FT Deep Cycle - 214 1300 475 132.3 lbs; 60.0 kg
Odyssey PC2250 Dual Purpose - 126 1225 240 86.0 lbs; 39.0 kg
Vmaxtanks VMAX MR197 Deep Cycle 4D 200 1120 450 112 lbs; 50.7 kg
Vmaxtanks VMAX XTR4D-200 Deep Cycle 4D 200 1250 470 130 lbs; 58.9 kg
Vmaxtanks VMAX XTR8D-350 Deep Cycle 8D 350 1700 780 185 lbs; 83.8 kg

Note: Amazon affiliate links in the table open in the new windows, feel free to check them for the latest offers.  This time table lists CCA values for the batteries.

Large deep AGM deep cycle batteries with capacity of 200+ Ah are generally able to provide 1000+ CCAs. They are large, heavy and store plenty of energy and although designed for cycling applications, they are obviously strong enough even for 1000+ CCA applications.

On the other hand dual purpose batteries weighing 65 to 85 pounds are generally able to provide 1000 CCAs (or almost 1000 CCAs).

Odyssey PC2250 is clearly the winner in 1000+ CCAs dual purpose battery class, at least regarding performances. However, it is also some 8 pounds heavier than PC2150 battery and 18 pounds(!) heavier than Exide XMC-31.

Again, when looking for the 1000+ CCA battery, Odyssey 31M-PC2150 is perhaps the best balanced battery.

For more about these batteries, check our Pick the Best 1000 CCA (Cold Cranking Amps) Marine Battery article.

odyssey 31m pc2150st m battery mFor Short: Odyssey 31M-PC2150 battery is not cheap and also not lightweight SLA AGM battery.

But, it is also one of the best balanced designs, very reliable in broad temperature range, with excellent electrical characteristics. It is worth its price, IMHO of course.

For more reviews and recommendations, check Odyssey 31M-PC2150 Marine Dual Purpose Battery Amazon link (link opens in the new window).