1-800-827-3232
Best Marine Starting Battery (2026): CCA, MCA and Lithium vs. AGM
Short answer: The best marine starting battery is one that meets or beats your engine's required cranking amps (CCA or MCA) and fits your battery tray. For the strongest sealed lead-acid choice, the Pro-Guide Group 31 AGM Starting battery delivers 1,150 MCA. For the lightest, the Group 24 Lithium Starting battery is rated at 1,000 CCA (lead-acid equivalent) and weighs 28.7 lb. For one battery that starts the engine and runs your electronics, choose a lithium dual purpose battery like the 31M180-DP.
A starting battery has one job: deliver a big burst of current to turn the engine over, every time, then recharge from the engine's charging system. This guide explains the ratings that matter and compares every Pro-Guide starting option.
Key Takeaways
- Your engine manual sets the minimum. Choose a battery that meets or exceeds its CCA or MCA requirement.
- MCA is higher than CCA for the same battery, because it is measured at 32°F instead of 0°F.
- AGM starting batteries are sealed and maintenance-free, with up to 1,150 MCA in our lineup.
- Lithium starting batteries are much lighter: 28.7 lb for 1,000 CCA (PbEq), compared with 42 to 60 lb for AGM.
- Don't use a starting battery for a trolling motor. Use a deep cycle or dual purpose battery for steady loads.
CCA vs. MCA: What the Ratings Mean
- Cold cranking amps (CCA) is the current a 12V battery can deliver for 30 seconds at 0°F while staying at or above 7.2 volts.
- Marine cranking amps (MCA) is the same test at 32°F. Because the battery is warmer, MCA is always higher than CCA. The Group 31 AGM Starting battery, for example, is rated at 925 CCA and 1,150 MCA.
- Reserve capacity (RC) is how many minutes the battery can supply 25 amps. It matters if you run accessories with the engine off.
- PbEq CCA on a lithium battery means lead-acid equivalent: the cranking performance compared with a lead-acid battery rated at that CCA.
Engine manufacturers list a minimum cranking rating, usually as CCA, MCA or both. Compare like with like. Meeting the requirement is the floor. Extra cranking reserve helps in cold weather and as a battery ages.
Best Marine Starting Batteries Compared
| Battery | Group | CCA | MCA | Weight | Warranty |
| Group 31 AGM Starting | 31 | 925 | 1,150 | 60 lb | 18-month free replacement |
| Group 27 AGM Starting | 27 | 750 | 935 | 50 lb | 18-month free replacement |
| Group 24 AGM Starting | 24 | 750 | 935 | 42 lb | 18-month free replacement |
| Group 24 Lithium Starting | 24 | 1,000 (PbEq) | — | 28.7 lb | 3-yr free replacement, 10-yr pro-rata |
| 31M180-DP lithium dual purpose | 31 | 1,000 (PbEq) | — | 41.9 lb | 3-yr free replacement, 10-yr pro-rata |
| 24M800 flooded (dealer) | 24 | 800 | 1,000 | 42 lb | 12-month free replacement, 30-month pro-rata |
| 27M800 flooded (dealer) | 27 | 800 | 1,000 | 49 lb | 12-month free replacement, 30-month pro-rata |
| 480 CCA flooded (dealer) | 24 | 480 | — | 34 lb | 12-month free replacement |
The Picks, Explained
Most cranking power (lead-acid): Group 31 AGM Starting
At 925 CCA and 1,150 MCA, the Group 31 AGM Starting battery is the strongest lead-acid cranking battery we make. It suits large outboards and inboards with a Group 31 tray. It is sealed, spill-proof and maintenance-free.
Best for Group 24 and 27 trays: AGM Starting
The Group 24 and Group 27 AGM Starting batteries both deliver 750 CCA and 935 MCA. The Group 24 weighs 42 lb and fits smaller trays. The Group 24 also lists 140 minutes of reserve capacity.
Lightest: Group 24 Lithium Starting
The Group 24 Lithium Starting battery is rated at 1,000 CCA (PbEq) and also stores 100Ah, all at 28.7 lb, about 13 lb less than a Group 24 AGM. Because lithium charging needs differ from lead-acid, confirm that your engine's charging system suits a lithium battery, or call our team before you switch.
Best value: 24M800 and 27M800 flooded (dealer)
Both flooded dual purpose batteries are rated at 800 CCA and 1,000 MCA, which is more cranking power than the Group 24 and 27 AGM starting batteries, at a lower up-front cost. They need periodic water checks and are sold through Pro-Guide dealers.
Starting vs. Dual Purpose: Do You Need Two Batteries?
Many boats run a dedicated starting battery for the engine and separate deep cycle batteries for the trolling motor and electronics. Keeping the starting battery separate means you can always start the engine, even after a long day on the trolling motor. Read Should You Run a Separate Battery for Your Boat Electronics?
On smaller boats with limited space, a dual purpose battery can do both jobs. The lithium 31M180-DP (180Ah) and 31M235-DP (235Ah) are each rated at 1,000 CCA (PbEq), with deep cycle capacity to spare.
How to Choose
- Find your engine's requirement in its owner's manual: minimum CCA, MCA or both.
- Match your tray size: Group 24, 27 or 31. See the battery group size chart.
- Choose the chemistry: AGM for sealed, maintenance-free cranking; lithium for the least weight; flooded for the lowest up-front cost.
- Decide on one battery or two: a dedicated starting battery, or a dual purpose battery that also runs accessories.
Frequently Asked Questions
What is the best AGM marine starting battery?
The Pro-Guide Group 31 AGM Starting battery, with 925 CCA and 1,150 MCA, is our strongest. For Group 24 or 27 trays, the Group 24 and 27 AGM Starting batteries each deliver 750 CCA and 935 MCA.
What is the difference between CCA and MCA?
Both measure cranking current for 30 seconds while the battery stays at or above 7.2 volts. CCA is measured at 0°F and MCA at 32°F, so MCA is always the higher number for the same battery.
How many CCA do I need for my boat?
Check your engine's owner's manual for its minimum cranking rating, then choose a battery that meets or exceeds it. Extra reserve helps in cold weather and as the battery ages.
Can I use a lithium battery as a marine starting battery?
Yes, if it is rated for starting. The Pro-Guide Group 24 Lithium Starting battery and the 31M180-DP and 31M235-DP dual purpose batteries are rated at 1,000 CCA (lead-acid equivalent). Confirm that your engine's charging system suits lithium before switching.
Can I use a starting battery to run my trolling motor?
No. Starting batteries are designed for short, high bursts of current. Use a deep cycle or dual purpose battery for trolling motors and electronics.
Shop Starting Batteries
Match your engine's cranking requirement and your tray size, then choose sealed AGM, lightweight lithium or a dual purpose battery that does it all.
SHOP THE GROUP 31 AGM STARTING
Also see lithium starting batteries and AGM batteries, or call our team at 1-800-827-3232 for help or to find a dealer.
Built for the Water. Powered by Pro-Guide.
