Group 65 Batteries - Dimensions, Features, and Recommendations

BCI Group 65 batteries are commonly used as automotive, marine, and industrial batteries. They are mid-size batteries, often designed as dual-purpose AGM batteries suitable as both starting and deep cycle batteries, thanks to the advances in AGM SLA battery technology.

Generally, group 65 batteries feature 70-75 Ah 20h capacity, 130-150 minutes RC, 750-950 CCA, with the MCA values of some models reaching almost 1100 Amps. Also, they usually weigh between 45 and 55 pounds (20 - 25 kg).

Lithium-ion BCI Group 65 batteries are not as common as AGM batteries, but they slowly appear on the market, offering many advantages over AGM batteries but also having certain limitations.

Updated: October 14, 2023.

BCI Group 65 Battery Dimensions

BCI Group 65 batteries dimensions are (L x W x H) 12 1/2 x 7 9/16 x 7 9/16 inches (12.0625 x 7.5625 x 7.5625 inches, 306 x 192 x 192 mm), or for short 12.1 x 7.5 x 7.6 inches.

Like most modern automotive, marine, and industrial lead-acid batteries, group 65 batteries are commonly made as Absorbent Glass Mat (AGM) Sealed Lead Acid (SLA) batteries, featuring improved vibration resistance, spill-proof design, low maintenance, etc.

Lithium-ion BCI Group 65 batteries are commonly based on IFR-26650 cells featuring LiFePO₄ (Lithium Iron Phosphate) chemistry. Their nominal voltage is 3.2 - 3.3V per cell, with the maximum recommended charging voltage of 3.5 - 3.6V per cell.

Newer lithium group 65 batteries feature flat cells, improving on capacity and charging/discharging currents. But, they are still relatively rare since group 65 batteries are normally used as starting or dual-purpose batteries, while LiFePO₄ chemistry is mostly used in deep cycle, high capacity batteries.

Automotive, marine, and industrial lithium-ion batteries commonly feature Battery Management Systems (BMS), which monitor the batteries' condition and, if required, protect the battery by shutting it off from the rest of the electric circuit.

The most popular BCI Group 65 batteries are given in the following table:

Note: Amazon affiliate links ('Model' column) open in the new windows, feel free to check them for the most up-to-date prices and offers.

Of course, there are other batteries on the market as well, but these are the most popular group 65 AGM batteries, especially ACDelco, NorthStar, and Odyssey Group 65 batteries.

As one can see, Absorbent Glass Mat (AGM) group 65 batteries are generally labeled as "Starting Batteries," but thanks to the AGM battery features, they tolerate deep discharges much better than wet/flooded lead acid batteries.

But keep in mind that lead-acid AGM starting or dual-purpose batteries don't cycle as well as true deep-cycle batteries.

BCI Group 65 Features

Generally, the most important group 65 battery features are:

• 70-75 Ah 20h capacity - when being drained for 20h, these batteries feature capacity in the 70-75 Ah range (3.5 - 3.75 Amps for 20h). Like all other AGM SLA batteries, when the discharge time is shorter, the actual capacity is decreased. Lithium-ion group 65 batteries feature 20h capacity, usually in the 100+ Ah range.
• 130-150 minutes RC (Reserve Capacity) - when being discharged with 25 Amps constantly, these batteries can operate for up to 130-150 minutes. RC value is very important for deep-cycle applications. RC value of lithium-ion batteries in this size is usually in the 200+ minutes.
• 750-950 CCA (Cold Cranking Amps) - group 65 batteries are able to provide 750-950 Amps for 30 seconds, with the voltage NOT dropping below 7.2V, at 0°F (-18°C). And that is rather cold, IMHO, of course.
• 950 - 1070 MCA (Marine Cranking Amps) or just CA (Cranking Amps) - group 65 batteries can provide 950 - 1070 Amps for 30 seconds, with the voltage NOT dropping below 7.2V, at 32°F (0°C).
• Weight between 45 and 55 pounds (20 - 25 kg) and can be more-or-less easily carried around by adults using built-in handles. Lithium group 65 batteries usually weigh around 11-14 kg, offering great weight savings.

Note: these values are given for the new, fully charged batteries, and in real life, one should not always expect such values, especially when the battery is in use for some time. For more about these values, check our Battery Terms and Abbreviations - Glossary article.

BCI Group 65 Recommendations

Group 65 batteries listed in the chart may be divided into several groups:

• batteries featuring CCA in 750-775 Amps range (ACDelco 65AGMHRC battery, Deka 9A65 battery, Delphi BU9065 65 battery),
• batteries featuring CCA in 900+ Amps range (ACDelco 65XAGM, NorthStar NSB-AGM65, Odyssey 65-PC1750T),
• lithium-ion battery, with extra long RC time and a large number of supported charging/discharging cycles.

ACDelco 65AGMHRC battery features 70Ah 20h capacity, 775 CCA, and 150 min RC. Also, it weighs 45.8 lbs (~20.75 kg).

Deka 9A65 battery features 75 Ah 20h capacity, 775 CCA, 955 MCA, 150 min RC, and it weighs 46 lbs (~20.85 kg).

Delphi BU9065 65 battery features 75 Ah 20h capacity, 750 CCA, calculated MCA of some ~930-940 Amps, 150 min RC, and it weighs 47.5 lbs (~21.5 kg).

Despite having the smallest 20h capacity of these three batteries, the ACDelco 65AGMHRC battery is rather comparable, even better than the Deka 9A65 and Delphi BU9065 65 batteries in some details (best MCA value, lightest design of these three batteries).

Also, the ACDelco 65AGMHRC battery features better reviews from actual users when compared with Deka 9A65 and Delphi BU9065 65 batteries - if you are looking for an affordable mid-range group 65 battery, consider ACDelco 65AGMHR battery.

NorthStar NSB-AGM65 vs. Odyssey 65-PC1750T

Once again, we have NorthStar vs. Odyssey battery comparison and once again, they are close, but not as close as in some other battery group sizes (for example, group 31 batteries NorthStar NSB-AGM31(M) and Odyssey 31M-PC2150 are so close that we still can't say which one is a better battery - and yes, author(s) of these articles are generally biased regarding Odyssey batteries due to the real-life situations at very low temperatures...).

When compared with the Odyssey 65-PC1750T battery, NorthStar NSB-AGM65 is somewhat heavier (55 vs. 54 lbs), it features a shorter Reserve Capacity (135 vs. 145 minutes), smaller CCA value (930 vs. 950 Amps), and smaller 20h capacity (69 vs. 74 Ah). Also, their MCA/CA values are exactly the same - 1070 Amps, and that is a lot of currents.

As a dual-purpose battery, NorthStar NSB-AGM65 is designed to withstand 900 cycles down to 50% of DoD (Depth of Discharge), while Odyssey 65-PC1750T tolerates up to 400 cycles down to 80% of DoD.

So, which one is better, NorthStar NSB-AGM65 or Odyssey 65-PC1750T? Since they feature very similar prices, we would say that the Odyssey 65-PC1750T is a better battery than the NorthStar NSB-AGM65.

But those numbers are 'just' numbers - both batteries are excellent group 65 batteries, and if the Odyssey 65-PC1750T is not available, feel free to get NorthStar NSB-AGM65.

Renogy 12V 100Ah Smart Lithium Iron Phosphate Battery - Model RBT100LFP12S-G1

Renogy RBT100LFP12S-G1 battery is a lithium-ion battery based on iron-phosphate chemistry (LiFePO₄), featuring a nominal voltage of 12.8 volts and 0.2C capacity of 100 Ah.

As the discharge rate is increased, its capacity also decreases, but not as nearly as the capacity of lead-acid batteries.

The physical dimensions of the battery are 11.4 x 6.8 x 7.4 inches (28.9 x 17.2 x 18.75 cm), and it weighs only 26 pounds (11.8 kg).

When the battery is being discharged at 0.2C rate (~20 Amps), it is able to withstand ~4000 (yes, four thousand!) charging/discharging cycles down to 80% DoD or ~7000 (again, seven thousand!) charging/discharging cycles down to 50% DoD.

The maximum continuous discharge current is 100 Amps, but the battery can also provide 130 Amps for 60 seconds. When the current reaches 150 Amps, BMS cuts the battery off, protecting it from any possible damage.

With a maximum charging current of 50 Amps, Renogy RBT100LFP12S-G1 may be charged rather quickly.

Renogy RBT100LFP12S-G1 is an excellent low-current (<100 Amps) performer, very light, with a large number of supported charging/discharging cycles.

Like all similar lithium batteries, Renogy RBT100LFP12S-G1 costs more than AGM batteries of similar capacity, making the initial investment larger but saving money in the long run.

Like with everything in life, the performances of these batteries also come at a certain price.

The price of these batteries varies depending on their features, brand, and if they are on sale or not - when choosing your next group 65 battery, consider their prices and features, but also your own requirements and preferences.

Group 65 850 CCA Battery

If we check the group 65 batteries comparison chart, we can see that there are several group 65 batteries that are able to provide 850 or more CCA Amps. These batteries are (Amazon links, links open in the new windows):

• ACDelco 65XAGM
• Full Throttle FT930-65
• NORTHSTAR NSB-AGM65
• Odyssey 65-PC1750T

Of these four, NorthStar and Odyssey models are the most popular ones. Also, their prices are often according to their performances, but what you pay is what you get.

If unsure, always check the reviews and comments of previous buyers.

Group 65 1000 CCA Battery

As one can see, there is no Group 65 battery on the market that can provide 1000 CCA.

NorthStar NSB-AGM65 and Odyssey 65-PC1750T are very close (930 CCA and 950 CCA, respectively) but not actually touching that magic "1000 CCA" mark.

However, when 1000+ CCAs are required, two group 65 batteries can be connected in parallel, surpassing the 1000 CCA mark considerably.

For true 1000+ CCA batteries, check our Pick the Best 1000 CCA (Cold Cranking Amps) Battery article.

How To Charge Group 65 Batteries

When the Group 65 battery is connected to the vehicle's electrical system, it should be properly charged by the onboard alternator and charging controller.

However, if there is a need to charge a lead-acid group 65 battery on the bench, one should use an intelligent 8-15 Amps battery charger that analyzes the battery first and only then starts the charging process.

Also, to protect the battery from undercharging and overcharging, a temperature probe is highly recommended.

Note: The actual charging current should be checked for every individual battery, but ~10 Amps is a safe way to go.

Before charging starts, the user should also set the exact battery chemistry: AGM, Gel-cell, Wet/Flooded, etc.

Lithium group 65 batteries can be recharged with stronger currents, often in the 30-50 Amps range, but lithium batteries MUST be recharged using dedicated lithium battery chargers or advanced lead-acid battery chargers with dedicated lithium battery charging mode.

Note: never, but really never, recharge a lithium battery with a battery charger that is not intended for exact lithium battery chemistry.

Long Story Short: BCI Group 65 Batteries are used for automotive, marine, industrial, security, medical, off-the-grid, and other similar applications where well-balanced, dual-purpose, low-maintenance batteries are required.

They differ in price, but they also differ in their features, so be sure to choose according to your own needs - if not sure, pay a little extra and go for Odyssey 65-PC1750T, NorthStar NSB-AGM65 or perhaps ACDelco XAGM battery.

If performances are not an absolute requirement, Deka 9A65, Delphi BU9065, and ACDelco 65AGMHRC have proved themselves to be good batteries in many real-life applications.