Group 47 (H5, L2, 55L2) Batteries - Dimensions, Features, and Recommendations

Group 47 (H5, L2, 55L2) batteries are medium-sized batteries, mostly used in automotive and light industrial applications as cranking or dual-purpose batteries for starting mid-range diesel and gas engines and for powering various electric and electronic devices while the main engine(s) are turned off.

Most BCI Group 47 (H5, L2, 55L2) batteries are designed as spill-proof, maintenance-free AGM batteries, but there are also other models on the market as well.

Updated: April 8, 2024.

Group 47/H5 Battery Dimensions and Specifications

Standard BCI Group 47 battery features dimensions of (L x W x H) 9 9/16 x 6 7/8 x 7 1/2 inches (9.5625 x 6.875 x 7.5 inches, 242 x 175 x 190 mm) and is very similar to the standard DIN H5 battery (also labeled as L2 battery) and EN 55L2 battery that has exactly the same physical dimensions of (L x W x H) of 242 x 175 x 190 mm.

The positive terminal is on the Right side of the battery when the battery is placed in front of the user.

Terminals are commonly automotive terminals, but there are also models with 'Nuts and Bolts' terminals.

The list of most popular BCI Group 47/H5 batteries is given in the following comparison chart:

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

On average, group 47 AGM battery features 20h capacity in the 55-60 Ah range, CCA value of 600-700 Amps, MCA value of 700-810 Amps, Reserve Capacity (RC) of 100-115 minutes, and weighs around 38-44 pounds (17-20 kg).

Sometimes it is very hard to distinguish "starting" from "dual-purpose" AGM batteries, and the group 47 batteries are no exception - AGM batteries are maintenance-free batteries that feature increased resistance to vibrations and mechanical impacts and tolerates deep discharges much better than starting wet/flooded lead-acid batteries.

While some batteries are labeled as "Starting," they are very often designed for "Stop&Go" ("Stop&Start") applications - they crank diesel and gas engines well, but they also accept charge quickly, tolerate medium to deep discharges well (not as true deep-cycle batteries, but better than "classic" starting batteries), etc.

Thus, dual-purpose batteries are often used in single-battery systems where the battery is required to power various systems while the main engine is off and still be able to crank the engine.

 Lithium Group 47/H5 Batteries

Lithium group 47/H5 batteries are not as common as lead-acid batteries, but they offer several advantages over lead-acid batteries, AGM models included:

• Lithium batteries are 2.5-3x lighter, leading to some weight savings,
• Lithium batteries feature somewhat higher nominal voltage, leading to better cranking,
• Lithium batteries feature a built-in BMS, which protects the battery from unwanted events,
• Lithium batteries are more energy-efficient,
• Lithium batteries are maintenance-free batteries that can operate in any position,
• Lithium batteries tolerate deep discharges much better than AGM batteries,
• Lithium batteries may feature a higher CCA rating, ensuring better cranking, etc.

However, group 47/H5 lithium batteries cost more than AGM lead acid batteries and are more sensitive to lower temperatures.

Note: there are several definitions of CCA rating, standard dependent, but the most common definition states that CCA (Cold Cranking Amps) rating is the maximum current that a new, fully charged, 12V battery can deliver for 30 seconds, with the voltage NOT dropping below 7.2V, at 0°F (-18°C).

First of all, lithium battery BMS will disconnect the battery before the battery reaches 7.2V, and the operation of lithium batteries at 0°F (-18°C) is questionable, to say the least.

Thus, many manufacturers claim a CCA rating for their batteries, but these Amps are often given for much higher temperatures and for shorter periods of time.

So, before buying a lithium starting battery, be sure to check its actual CCA/MCA/HCA rating. And if you live in an area with really cold winters, go for a good AGM battery, and don't look any further.

Group 47/H5 Equivalent/Similar Battery Groups

The physical dimensions of the group 47 batteries are very similar to several other BCI battery groups, allowing these batteries to be used almost interchangeably.

Here is the list of several such groups with their maximum dimensions (L x W x H):

• Group 47: 9.5625 x 6.875 x 7.5 inches (242 x 175 x 190 mm),
• Group 78: 10.25 x 7.0625 x 7.3125 inches (260 x 179 x 186 mm),
• Group 35: 9.0625 x 6.875 x 8.875 (230 x 175 x 225 mm), etc.

There are other battery groups of similar size, and they all differ in one or more dimensions. Also, one has to be careful about battery type, chemistry, terminal type, orientation, and similar when replacing one battery group with another.

How to Charge Group 47 (H5, L2, 55L2) Batteries

Group 47/H5 batteries should be recharged by the electric system of the vehicle, mostly consisting of the alternator and the charge controller.

However, if for some reason these batteries must be recharged by an outside power source, use an advanced AGM battery charger that also may act as a battery maintainer - when the battery is fully recharged, the battery charger automatically switches itself into the maintenance mode.

Since these batteries feature a nominal capacity in the 55-60 Ah range, the battery charger with 5-7 Amps charging current is recommended.

Note: these batteries generally tolerate even stronger charging currents, but at 5-7 Amps, they will not be overstressed in any way.

One of such battery chargers is a NOCO Genius 5 Smart Car Battery Charger. It can be used to charge 6V and 12V lead-acid batteries and 12V lithium (LiFePO₄)batteries at a rate of 5A, to repair deeply discharged 12V lead-acid batteries, etc.

Also, after fully recharging the battery, it switches itself automatically in maintenance mode to keep the battery fully charged even when the battery is stored for a long time.

For example, if the 60Ah battery is discharged down to 50% DoD, NOCO Genius 5 can recharge the battery (30Ah required) in 6.5-7 hours, depending on the battery's condition.

Thanks to its features, NOCO Genius 5 Smart Car Battery Charger (Amazon link, opens in the new window) is one of the most popular battery chargers in its class.

Long Story Short: if you are looking for a new group 47 lead-acid battery, go for a good AGM battery from a reputable brand, just be sure to check the battery CCA/Ah rating, terminal type and orientation, base hold-down type, etc.

If you are looking for a way to save some weight in your vehicle or industrial application, lithium group 47/H5 batteries are not as common as AGM batteries, but they are, nonetheless, present on the market.