Duralast 27DP DL Specs

The Duralast 27DP DL is a deep-cycle marine battery designed to provide reliable power for boats. In this review, we will take a close look at the key specifications and performance features of the Duralast 27DP DL to see how it stacks up for marine use.

Specification Details
Battery Technology Flooded Lead-Acid
Warranty 1 Year
Group Size 27
Cold Cranking Amps 800 Amps
Cranking Amperage 0 Amps
Reserve Capacity 130 Minutes
Price $112.99
Terminal Type SAE
Terminal Location Front Top
Weight 51.7 lbs
Voltage 12V
Length 12.06 in
Width 6.81 in
Height 8.88 in
Battery Type Deep Cycle
Marine Cranking Amps 1000 Amps
Top Features Solidium welds, optimized grids, safe vent caps

Battery Technology

The Duralast 27DP DL utilizes conventional flooded lead-acid battery technology. The battery contains lead plates submerged in an electrolyte solution of sulfuric acid and water.

This is a proven battery chemistry known for its affordability and dependable performance. When the battery discharges, a chemical reaction takes place, releasing electrons and converting the lead into lead sulfate at the battery plates.

Recharging the battery reverses the reaction. Compared to sealed, maintenance-free batteries, the flooded design does require occasional checking and topping off of the electrolyte.

However, flooded batteries tend to have lower internal resistance and better capacity for repeated deep cycling service. This makes them a popular choice for the rigorous demands of marine applications.


The Duralast 27DP DL battery comes with a standard 1-year replacement warranty. While not the most extended coverage compared to some premium AGM batteries, this does provide peace of mind against early failure defects.

The warranty is valid if the battery is used in the proper application and maintained according to specifications.

Group Size

The Duralast 27DP DL belongs to group size 27 batteries. The group size refers to the dimensions of the battery, which are standardized to ensure compatibility across different battery brands.

Group 27 batteries have a length of 12.06 inches, width of 6.81 inches, and height of 8.88 inches. The 27DP DL weighs 51.7 pounds. Being a large battery group size, the Duralast 27DP DL requires a special oversized battery box to accommodate the footprint.

Cold Cranking Amps

An important specification for starting batteries is the cold cranking amps (CCA) rating, which measures the battery’s ability to start an engine in cold temperatures. The Duralast 27DP DL has a CCA rating of 800 amps.

This high power output will provide plenty of starting current even during cold winter. The marine cranking amp (MCA) rating is even higher at 1000 amps to account for the increased loads on marine engines.

Cranking Amperage

In contrast to the cold cranking and marine cranking specs, the basic cranking amperage for the Duralast 27DP DL is rated at 0 amps. This number only applies to warm engine starting scenarios around 80°F where minimal current is needed.

For virtually all practical purposes, it’s the CCA and MCA ratings that matter in real-world operations. The 0 amp basic cranking amp spec does not indicate poor performance.

Reserve Capacity

An important specification for dual-purpose marine batteries is the reserve capacity. This indicates how long the battery can continuously deliver a useful discharge current in case the alternator fails.

The Duralast 27DP DL has a reserve capacity of 130 minutes until the battery is discharged to 1.75V/cell at 25 amps, which is ample for most boats.

The actual reserve time will vary based on the current draw. With 182 minutes at a lighter 12 amp discharge, the Duralast 27DP DL provides all-day reserve power.


With an MSRP of $112.99, the Duralast 27DP DL hits a reasonable price point for a flooded marine battery in this performance range. More affordable options typically cut back on cycle life, while premium AGM models can cost two or three times as much.

Given the proven durability of Duralast batteries, the Duralast 27DP DL represents a high-value option. Discounts from auto parts stores can bring the price down further.

Terminal Locations

The battery terminals are located on the standard group 27 front top layout. The positive post is on the front left, and the negative post is on the front right.

Both terminals use a threaded SAE bolt-on connector. This makes it easy to swap out battery cables and accessories without tools. The side and top terminal location allows for flexibility in mounting configurations.


At 51.7 pounds, the Duralast 27DP DL is a fairly hefty battery. The large case size and thick lead plates needed to deliver the high power output require substantial weight.

The battery does come equipped with integrated top-mounted carry handles to make transporting and installation more manageable. The weight also provides inherent stability when installed on board.


The Duralast 27DP DL runs on a typical 12-volt system. Multiple 12-volt batteries can be combined in parallel or series to power 24-volt and 36-volt marine electrical loads.

When connected in parallel, the voltages remain the same while the overall capacity doubles. In series, the voltage adds while capacity remains constant. This versatility makes the Duralast 27DP DL useful for multi-battery bank configurations.

Additional Features

Some other worthwhile features include the optimized Solidium welds on the battery terminals to prevent corrosion and increase durability.

The patented grid manufacturing technology enhances efficiency and runtime. Vent caps are designed for safety and to minimize leakage.

Overall, the Duralast 27DP DL makes an excellent choice as a dual-purpose starting and deep cycling battery for marine applications where reliable power is a must.

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