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A boat that will not start at the ramp, a fish finder going dark halfway across the lake, a trolling motor fading before the day ends: each is a moment when the battery figures matter. This guide explains marine battery prices: what the capacity, cranking, size and warranty figures on a listing mean, and how to read them before you buy. Read the capacity first, then the cranking figures, then the size and build, and finish with the warranty.
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The quick answer
Marine battery prices move with the figures on the listing: capacity in amp-hours, cranking amps, group size, cycle life and warranty term. The listings here state a 12V 110Ah Group 31M AGM battery with 825 CCA, 1000 MCA and 240 RC, and a 12V 92Ah Group 27M AGM battery with 800 CCA and 175 RC. A dual-purpose battery covers starting and deep cycle use in 1 battery. Read the capacity first, then the cranking figures, then the size, and finish with the warranty term.
Step 1: Read the capacity first
Capacity in amp-hours is the headline figure on a marine battery listing. The Mighty Max listing states 110Ah in a Group 31M deep-cycle marine AGM battery, built for dual-purpose starting and deep discharge. The UPLUS listing states 92Ah at a 20 hour rate in a Group 27M dual purpose AGM battery. A higher amp-hour figure means more stored energy on the listing, and the 20 hour rate is the rate the 92Ah figure is stated at. The Mighty Max listing also states up to 700 cycles at 50% depth of discharge, a durability figure the UPLUS listing does not state. For the dual-purpose type, see the best dual purpose marine batteries.
| Battery | Capacity stated | Type stated | Cycle life stated |
|---|---|---|---|
| Mighty Max MM-G31M | 110Ah | AGM dual-purpose | Up to 700 cycles at 50% |
| UPLUS Group 27M | 92Ah at 20 Hr | AGM dual purpose | Not stated |
Both listings describe dual-purpose batteries, which combine starting and deep cycle use in 1 battery, so the buyer carries 1 battery instead of 2. The UPLUS listing states the dual-purpose design frees up space in the boat and simplifies the electrical system.
Step 2: Read the cranking figures
Cranking figures tell you how the battery starts an engine. The Mighty Max listing states 825 CCA and 1000 MCA, with 240 RC. The UPLUS listing states 800 CCA and 175 RC, and states the battery starts engines from 70 to 350 hp. CCA is the cold cranking amps figure, MCA is the marine cranking amps figure, and RC is the reserve capacity figure, and all three come from the listing. The Mighty Max bullets state 1000 CA in one place while the title states 1000 MCA, so read the title figure. For the battery types, see what a deep cycle marine battery is.
Step 3: Check size, weight and build
Group size, dimensions and weight decide whether the battery fits the boat. The Mighty Max listing states Group Size 31M, dimensions of 13.00 by 6.81 by 8.35 inches with a 9.37 inch total height, and a weight of 70.70 lbs in its bullets. The UPLUS listing states BCI Group 27M, dimensions of 6.61 by 12.05 by 9.11 inches, and a weight of 49.0 pounds. The Mighty Max listing states a rugged ABS shell, a spill-proof maintenance-free design, and vibration resistance for waves and rough terrain, with all-season versatility for boaters who need strong cranking power and steady energy for electronic accessories. The UPLUS listing states thicker full frame cast plates, sealed AGM construction, and vibration resistance for wave pounding and trailer transport, and lists the battery for navigation devices, lights and engines. Read the dimensions with care: the Mighty Max spec table lists 72.5 pounds and 13.0 by 6.81 by 9.37 inches, which does not match the 70.70 lbs and 8.35 inch height in the bullets, so trust the title and bullets over the spec table.
Step 4: Read the warranty
Warranty terms are stated on the listing, and they differ across the listings. The UPLUS listing states a 2 Year Warranty. The Mighty Max listing states a 2-year limited warranty in its bullets and a 1 Year Manufacturers Warranty in its spec table, so the listing disagrees with itself on the term. Neither listing states a certification. Read the warranty term the listing states before you buy, and note when a listing disagrees with itself.
Ways to use marine battery prices
- Match the capacity to the load: 110Ah at Group 31M with up to 700 cycles at 50%, or 92Ah at 20 Hr at Group 27M with no cycle figure stated.
- Match the cranking to the engine: 825 CCA and 1000 MCA with 240 RC, or 800 CCA and 175 RC for engines from 70 to 350 hp.
- Match the size to the battery box: Group 31M at 13.00 by 6.81 by 8.35 inches and 70.70 lbs, or Group 27M at 6.61 by 12.05 by 9.11 inches and 49.0 pounds.
- Match the warranty to the plan: a 2 Year Warranty on the UPLUS listing, and a listing that disagrees with itself on the Mighty Max term.
FAQ: power away from the grid
What size marine battery do I need?
Match the group size to the battery box and the amp-hours to the loads. The listings here state Group 31M at 110Ah and Group 27M at 92Ah, so read the group size and the capacity the listing states. The Mighty Max listing states dual-purpose starting and deep discharge, and the UPLUS listing states starting and deep cycle use.
What does CCA mean on a marine battery?
CCA is the cold cranking amps figure the listing states. The Mighty Max listing states 825 CCA and 1000 MCA, and the UPLUS listing states 800 CCA.
How many cycles does a marine AGM battery last?
The Mighty Max listing states up to 700 cycles at 50% depth of discharge. The UPLUS listing states no cycle figure.
What warranty comes with a marine battery?
The UPLUS listing states a 2 Year Warranty. The Mighty Max listing states a 2-year limited warranty in its bullets and a 1 Year Manufacturers Warranty in its spec table, so the listing disagrees with itself on the term.
Related solar guides
See the best dual purpose marine batteries, the marine battery types, the RV battery vs marine battery and the marine battery maintenance. For charging, see the best marine battery chargers with a plug.
