Group 34 Batteries - Dimensions, Features, and Recommendations

Group 34 batteries are medium-large but still rather powerful batteries, featuring 20h capacity in the 50-75 Ah range, providing 750-900 CCA, 100-145 minutes of Reserve Capacity, etc. Their weight depends on the chemistry, battery type, and internal construction, and it ranges between 37 and 51 pounds (16.8 - 23.1 kg).

BCI group 34 batteries are commonly used in automotive, marine, industrial, and off-the-grid applications in the form of starting, dual-purpose, and deep cycle batteries, offering good starting/cranking characteristics, a large number of charging/discharging cycles and excellent deep cycle recovery - battery type-dependent, of course.

Updated: June 16, 2023.

Group 34 Batteries Physical Dimensions

BCI group 34 batteries' physical dimensions are (L x W x H) 10.25 x 6.8125 x 7.875 inches (26 x 17.3 x 20 cm), with the weight varying between 37 and 51 pounds.

BCI group 34 batteries are very similar in size to BCI group 24 batteries (10.25 x 6.8125 x 8.875) - group 24 batteries are 1 inch taller.

Also, some manufacturers offer batteries labeled as 34/78, featuring terminals standard for group 34 batteries, but also with the side terminals in the form of 3/8” receptacle. Such batteries are often slightly larger than group 34 batteries - check their actual dimensions and your battery compartment before making a purchase.

BCI group 34 battery weight depends on the battery construction, chemistry, type, etc., and differs significantly, but generally, they weigh from 37 to 51 pounds.

Most of these batteries feature convenient handle(s) for carrying them around, and since they are 'not too heavy', many people tend to carry them even on longer distances - if you are not used to such activities, be aware that these batteries are heavy enough to cause muscle inflammation and cramps, to say the least :)

Group 34 Batteries vs. Group 34R Batteries

Generally, the only difference between group 34 batteries and group 34R batteries is the terminal post orientation.

While 34 group batteries feature a positive terminal on the left, 34R group batteries feature a positive terminal on the right, hence the 'R' letter after '34'.

Most popular brands manufacture their group 34 batteries in both '34' and '34R' versions, so if '34R' models are required, they shouldn't be a problem to purchase even via online shops.

Group 34 Batteries Features

The following table lists the most popular BCI group 34 batteries:

Note: Amazon links (first, 'Model' column) open in the new windows, feel free to check them for the most up-to-date offers and prices. Also, the MCA value for the VMAXTANKS XTR34-75 battery is calculated from its HCA (1100 Amps) and is not an official value.

As one can see, there are almost no lithium-ion drop-in replacement batteries in the chart. The reason is simple - group 34 batteries are typically used as starting batteries in vehicles weighing 3-4000 pounds or more, so saving 20-30 pounds doesn't improve a vehicle's performance much.

Most of group 34/34R batteries feature AGM construction, but there are exceptions, for example, the Banshee 34M battery, which is a flooded lead-acid battery - according to the manufacturer, this battery is based on the "Enhanced Flooded Battery" technology and is also maintenance free. But, IMHO, it is still a flooded lead-acid battery.

Features of the group 34 batteries depend on the intended use - starting/cranking group 34 batteries and dual purpose/deep cycle group 34 batteries.

Starting/Cranking Group 34 Batteries

Starting/cranking group 34 batteries feature Cold Cranking Amps (CCA) in the 740-800 Amps range, nominal 20h capacity between 50 and 60 Ah and Reserve Capacity (RC) value of 100-120 minutes. Their weight varies between 37.9 and 44.5 pounds.

Note: there are other starting group 34 batteries on the market that may have somewhat different values.

• ACDelco 34AGM battery features a nominal 20h capacity of 60 Ah, 740 CCA Amps, 115 minutes RC and it weighs 38.7 pounds.
• Delphi BU9034 battery features a nominal 20h capacity of 55 Ah, 775 CCA Amps, 120 minutes RC and it weighs 44.5 pounds.
• DieHard 38232 battery features a nominal 20h capacity of 55 Ah, 775 CCA Amps, 120 minutes RC and it weighs 44.5 pounds.
• Optima RedTop 34 battery features a nominal 20h capacity of 50 Ah, 800 CCA Amps, 100 minutes RC and it weighs 37.9 pounds.

As starting batteries, these batteries are not intended for deep cycle, standby, off-the-grid and similar applications - they are designed and built to reliably supply large amounts of energy for short periods of time.

Optima RedTop 34 AGM battery features the lowest 20h capacity (50 Ah) and shortest RC value of 100 minutes, but it is also the strongest of all of these batteries featuring 800 Amps CCA (vs. 740-775 CCA of other batteries).

Also, thanks to its spiral-wound cells, Optima RedTop 34 AGM battery is the lightest of these batteries.

Optima Batteries manufactures several starting group 34 batteries:

• Optima RedTop 8002-002 34,
• Optima RedTop 8003-151 34R,
• Optima RedTop 8004-003 34/78,
• Optima BlueTop 8006-006 34M,

This allows the user to pick the right battery for the job.

But performances often come at a certain price.

Since 20h capacity and Reserve Capacity are not of much importance for starting batteries, one may safely ignore them.

If the batteries are required for applications where 20h capacity and RC value do matter, then one should consider dual-purpose or even deep cycle group 34 batteries.

Dual Purpose/Deep Cycle Group 34 Batteries

Dual purpose/deep cycle group 34 batteries are generally heavier and cost more than starting group 34 batteries.

The reason for this is simple - both dual-purpose and deep cycle batteries must be very sturdy and robust batteries, ready to provide plenty of energy in short amounts of time. But, they also must be able to tolerate cyclic use and deep discharges.

Thus, dual-purpose group 34 batteries feature CCA in the 750 - 880 Amps range (some 80 Amps more than the strongest starting group 34 battery!!!), they feature nominal 20h capacity between 60 and 68 Ah, and have RC values between 120 and 135 minutes.

Note: Banshee 34M features an RC value of 100 minutes and it is advertised by the manufacturer as dual purpose group 34 battery - it features 750 CCA and is able to withstand 400 cycles down to 80% DoD. But, it is a flooded lead-acid battery, and although it is a maintenance-free battery, it is still a flooded battery and personally, I don't recommend flooded lead-acid batteries anymore, EXCEPT perhaps for large(r), off-the-grid, stationary battery banks! But that is a completely different story ...

Exide Edge FP-AGM34 battery features a nominal 20h capacity of 60 Ah, 770 CCA Amps, 120 minutes RC and it weighs 45.9 pounds.

NorthStar NSB-AGM34 battery features a nominal 20h capacity of 65 Ah, 880 CCA Amps, 1050 MCA, 134 minutes RC and it weighs 51 pounds. According to the manufacturer, it tolerates ~900 cycles, down to 50% DoD (with no mention of nominal capacity % loss!).

Odyssey 34M-PC1500 battery features a nominal 20h capacity of 68 Ah, 850 CCA Amps, 1050 MCA, 135 minutes RC and it weighs 49.5 pounds. It tolerates ~400 cycles, down to 80% DoD with the capacity drop down to 80% of nominal value.

Odyssey Batteries manufactures several batteries of this size and are also labeled as 'group 34 batteries'; they are slightly longer (10.25 vs. 10.86 inches). These batteries include models:

• Odyssey 34-PC1500: 'standard' group 34 battery featuring SAE-only terminals.
• Odyssey 34R-PC1500: very similar to the 34-1500 model, it features SAE-only terminals, but terminal sides are reversed.
• Odyssey 34M-PC1500: 'standard' terminal orientation, but it also features additional terminals for marine applications - SAE terminals, 3/8” Stud (Positive), and 5/16” Stud (Negative) terminals. Note: Odyssey 34M-PC1500 features a CCA value of 880 Amps!
• Odyssey 34/78-PC1500: 'standard' terminal orientation, but it features top SAE terminals and side terminals in the form of a 3/8” receptacle. Note: Odyssey 34/78-PC1500 is also slightly wider than other group 34 batteries - 7.09 inches (180.1 mm), making it both longer and wider than the 'standard' 34 battery.

Optima 8016-103 D34M battery features a nominal 20h capacity of 55 Ah, 750 CCA Amps, 870 MCA, 120 minutes RC and it weighs 43.5 pounds.

Optima Batteries manufactures several very popular dual-purpose group 34 batteries, including Optima YellowTop 8012-021 D34, Optima YellowTop 8014-045 D34/78, and Optima BlueTop 8016-103 D34M.

They all feature the same design and general features but differ in intended use and, thus, terminals.

Optima dual-purpose batteries are suitable for various roles like trolling motor battery, fish finder battery, wheelchair battery, vehicle battery, for various off-the-grid applications, just note that it is a somewhat lighter group 34 battery, and due to the spiral wound cells, it features good starting characteristics and moderate RC and nominal capacity, when compared with other dual purpose/deep cycle group 34 batteries.

VMAXTANKS XTR34-75 is labeled as a deep cycle battery, and it features a nominal 20h capacity of 75 Ah, 1100 HCA Amps, 145 minutes RC and it weighs 45.0 pounds. It tolerates ~500 cycles, down to 80% DoD with the capacity drop down to 80% of nominal value.

VMAXTANKS XTR34-75 is a true deep cycle AGM battery - it features 1100 HCA and ~825 MCA (calculated value). But, it is not what this battery is designed for.

When compared with other dual purpose/deep cycle group 34 batteries, VMAXTANKS XTR34-75 features the largest nominal 20h capacity of 75 Ah and Reserve Capacity of 145 minutes.

Also, it is not the heaviest of them all.

The flooded Banshee 34M and spiral wound Optima D34M batteries are lighter dual-purpose/deep cycle group 34 batteries, while other batteries (Exide Edge FP-AGM34, NorthStar NSB-AGM34, and Odyssey 34M-PC1500) are slightly heavier.

VMAXTANKS XTR34-75 is suitable for various deep cycle operations like wheelchair batteries, off-the-grid batteries, security and standby systems, as trolling motor batteries, etc.

XS Power D3400 batteries come in 65Ah and 80Ah versions, with the 65Ah model being more common.

XS Power D3400 12V 65Ah is an AGM SLA dual-purpose battery designed as an automotive battery in single and dual-battery systems for powering not only engine starters but also powering broad range of onboard electric and electronic systems, including multimedia devices (high output stereos, for example), various winches, pumps, lights and similar.

XS Power D3400 batteries are high-out batteries and are one of the most popular premium group 34 batteries, comparable with NorthStar and Odyssey group 34 batteries.

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

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Long Story Short: If you are looking for a new Group 34 battery, consider one of these models.

These batteries differ in terms of chemistry (mostly are AGM, but flooded cells are still going on strong), battery type, terminals, weight, starting and deep discharge performances, and in the end, price.

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.

Since these batteries are not the cheapest on the market, before ordering, be sure to check the specifications of your old battery and compare it with the batteries in the chart - go for the same or better battery/batteries, taking into account even your own needs and requirements.

Note: whatever you do, stay safe. These batteries pack a lot of energy and can provide a serious energy burst!