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800 CCA Group 24 Marine Battery: Pro-Guide 24M800 Starting Guide
Short answer: If you need maximum starting power but your boat only has room for a Group 24 battery, the Pro-Guide 24M800 is built for the job. This 12V flooded lead-acid marine battery delivers 800 cold cranking amps (CCA) and 1,000 marine cranking amps (MCA) in a standard Group 24 case (10 1/4 x 6 13/16 x 8 7/8 in), with 135 minutes of reserve capacity at 25 amps for accessories. That is 300 more CCA than the Pro-Guide 24M500 in exactly the same footprint.
Bigger outboards, cold spring launches and boats loaded with electronics all ask more of a starting battery. This guide explains when an 800 CCA Group 24 battery makes sense, how to match cranking amps to your engine, what the 24M800's reserve capacity can run, and how to charge and care for a flooded battery so it keeps starting strong.
Key Takeaways
- Serious cranking power: 800 CCA and 1,000 MCA, the highest cranking ratings in the Pro-Guide flooded dual purpose lineup (tied with the Group 27 27M800).
- Compact case: standard Group 24 dimensions, 10 1/4 x 6 13/16 x 8 7/8 in, so it fits common Group 24 boxes and trays.
- Accessory backup: 135 minutes of reserve capacity at 25 amps, according to the product description and battery label.
- Weight: 42 lb (19.1 kg).
- Warranty: 12 months free replacement and 30 months total pro-rata coverage.
Why Choose an 800 CCA Group 24 Marine Battery?
Group 24 is a Battery Council International (BCI) case size, and it is one of the most common marine battery slots. The size sets the outside dimensions, which limits how much lead and electrolyte fit inside. Many Group 24 batteries land somewhere in the 500 to 650 CCA range. The 24M800 packs 800 CCA into the same case.
Why does that matter? Cranking amps are your margin. A battery's ability to deliver current drops as temperature falls, as the battery ages and as its state of charge drops after a long day of running electronics. A battery that just barely meets your engine's requirement on a warm day can struggle on a cold morning in April. Extra cranking amps give you a buffer for all three.
The 24M800's label reads Starting, and Pro-Guide lists it as a dual purpose battery. In practice that means its first job is turning over your engine reliably, with reserve capacity to keep your fish finder, lights and bilge pump running when the motor is off.
Pro-Guide 24M800 Specifications
| Model / SKU | Pro-Guide 24M800 (PGM24M800) |
| Type | Flooded lead-acid, starting / dual purpose |
| Voltage | 12V |
| BCI group size | 24 |
| Cold cranking amps (CCA) | 800 |
| Marine cranking amps (MCA) | 1,000 |
| Reserve capacity (RC) | 135 minutes at 25 amps (product description and label) |
| Charge current | 10A standard, 15A maximum |
| Terminals | 1 SAE post, 1 stud terminal |
| Dimensions | 10 1/4 x 6 13/16 x 8 7/8 in (260.3 x 174.6 x 228.6 mm) |
| Weight | 42 lb (19.1 kg) |
| Warranty | 12 months free replacement, 30 months total pro-rata |
Need a copy for your records? Download the 24M800 data sheet (PDF).
The 24M800 label lists 1,000 MCA, 800 CCA and 135 minutes of reserve capacity, all in a standard Group 24 case.
How Many Cranking Amps Does Your Outboard Need?
The only reliable answer is in your engine's owner's manual. Outboard manufacturers list a minimum battery rating, usually in MCA, CCA or both, and it varies by engine size and model. Here is how to use it:
- Find the minimum rating in the manual or on the manufacturer's website. Note whether it is given in MCA or CCA.
- Compare like with like. MCA is measured at 32°F and CCA at 0°F, so MCA is always the higher number. The 24M800 is rated 1,000 MCA and 800 CCA.
- Add a margin. If you fish in cold weather, run a lot of electronics with the engine off or keep a battery for several seasons, choosing a battery above the minimum gives you headroom.
- Check the case size. Make sure your tray or box takes a Group 24. If it is sized for Group 27, the Pro-Guide 27M800 offers the same 800 CCA with more reserve capacity.
What do the ratings mean?
- CCA (cold cranking amps): current delivered for 30 seconds at 0°F while holding a usable voltage.
- MCA (marine cranking amps): the same test at 32°F, closer to typical boating temperatures.
- RC (reserve capacity): minutes the battery can supply 25 amps before reaching 10.5 volts.
What Can 135 Minutes of Reserve Capacity Run?
Reserve capacity tells you how much accessory power you have. At 25 amps, 135 minutes works out to roughly 56 amp-hours delivered at that rate. Because this battery also has to start your engine, plan to use only about half of that, roughly 28 amp-hours, before recharging. Rough estimates:
| Load | Typical draw | Rough runtime to about 50% |
| Single fish finder | About 1.5A | About 18 hours |
| Two graphs plus nav lights | About 4A | About 7 hours |
| Bilge pump running | About 5A | About 5 to 6 hours |
| Livewell pump, graphs and lights | About 10A | About 3 hours |
Real runtime depends on temperature, battery age and how often loads cycle on and off. Lead-acid batteries usually deliver a bit more total capacity at light draws than the RC test implies, and less in the cold. If you run big electronics all day with the engine off, consider a separate house battery. See Should You Run a Separate Battery for Your Boat Electronics?
Flooded Starting Battery vs. AGM vs. Lithium
Here is how a flooded starting battery like the 24M800 typically compares with the other chemistries for a starting job:
| Factor | Flooded (Pro-Guide 24M800) | Typical AGM | Typical lithium (LiFePO4) |
| Cost per cranking amp | Usually lowest | Higher | Highest |
| Maintenance | Periodic water and terminal checks | Sealed, no watering | Sealed, no watering |
| Mounting | Upright, ventilated location | Sealed, more flexible | Sealed, more flexible |
| Charging | Standard flooded profile | AGM profile | Lithium profile required |
| Best fit | Value-focused starting power | Hard-to-reach installs, high vibration | Weight savings, deep cycling |
For most anglers who can reach their battery and want the most cranking power for the money, flooded is hard to beat. If you would rather never open a cap, look at our AGM batteries. If you are chasing weight savings, see our starting lithium batteries.
What Is the 24M800 Best For?
- Larger outboards in a Group 24 tray: when your engine calls for more cranking power than a typical Group 24 provides.
- Cold-weather launches: spring and fall anglers who need 800 CCA of margin when temperatures drop.
- Cranking battery for a bass or multi-species boat: pair it with a dedicated trolling motor bank and let the 24M800 focus on the engine. Our trolling motor battery setup guide explains how to wire the rest of the system.
- Upgrading from a weaker Group 24: the 24M800 shares its case size and terminal layout with the Pro-Guide 24M500, so it drops into the same space with more power.
Because the 24M800 is a cranking-focused battery, it is not the right choice to power a trolling motor day after day. For that, use a deep cycle battery such as the Pro-Guide 24M140 or a lithium deep cycle bank.
Same Group 24 footprint as the 24M500, with 300 more cold cranking amps.
How to Charge the 24M800
Pro-Guide rates the 24M800 for a 10-amp standard charge and a 15-amp maximum. Follow these basics:
- Use a marine charger with a flooded lead-acid setting that tapers current and switches to float when the battery is full.
- Stay at or below 15 amps. The Pro-Guide 12V 10A 1-Bank Battery Charger matches the 10A standard rate. For boats with a cranking battery plus a trolling motor bank, a multi-bank charger such as the 12V 10A 3-Bank or 12V 10A 4-Bank keeps every battery topped up.
- Recharge after every trip. A lead-acid battery left partially discharged slowly loses capacity to sulfation, and that shows up first as weaker starts.
- Ventilate. Flooded batteries typically vent small amounts of hydrogen near the end of a charge, so charge away from sparks and flames.
As a rough estimate, replacing about 28 amp-hours with a 10A charger takes around three to four hours, allowing for normal charging losses and the slower top-off stage.
Cold-Weather and Maintenance Tips
Keep it fully charged in the cold
Cold reduces the current any lead-acid battery can deliver, and a discharged battery can freeze. Start every cold-weather trip with a full charge and you get the most out of all 800 CCA.
Check the electrolyte
Flooded batteries typically lose some water over time, especially in hot weather or with heavy charging. Check monthly during the season that the plates are covered, and top up with distilled water only, preferably after charging. Do not overfill, and wear eye protection.
Clean, tight connections
High cranking current is unforgiving of corroded or loose connections. Clean the posts, tighten the cable ends and coat them with battery corrosion preventative spray.
Secure it
Mount the battery upright and strap it down. The NOCO Group 24 Snap-Top Battery Box and NOCO Group 24 Battery Tray are sized for Group 24 batteries like the 24M800.
Plan for winter
Before storage, charge fully, disconnect and keep it on a maintainer or recharge every few weeks. Our marine battery maintenance guide covers the full routine. Keep a 12V 1000A Jump Starter aboard for peace of mind.
24M800 vs. 27M800: Which Should You Choose?
Both Pro-Guide batteries are 12V flooded designs rated 800 CCA and 1,000 MCA with a 10A / 15A charge rating. The difference is size and reserve capacity:
| Spec | 24M800 | 27M800 |
| Group size | 24 | 27 |
| Length | 10 1/4 in | 12 1/16 in |
| Reserve capacity | 135 minutes | 182 minutes |
| Weight | 42 lb | 49 lb |
Choose the 24M800 if your tray, box or compartment is sized for Group 24, or if you want the cranking power without the extra length and weight. Choose the 27M800 if you have a Group 27 space and want about 47 more minutes of reserve capacity for accessories.
Frequently Asked Questions
Is 800 CCA a lot for a Group 24 battery?
Yes. Many Group 24 batteries are rated well below that. The Pro-Guide 24M800 delivers 800 CCA and 1,000 MCA in a standard Group 24 case.
How many cranking amps do I need for my outboard?
Check your engine owner's manual for the minimum MCA or CCA rating, then choose a battery that meets or exceeds it. Extra cranking amps help in cold weather and as the battery ages.
What is the difference between CCA and MCA?
CCA is measured at 0°F and MCA at 32°F, so MCA is always higher. The 24M800 is rated 800 CCA and 1,000 MCA.
Can the 24M800 run a trolling motor?
It is a cranking-focused battery and is not designed for repeated deep discharges. Use a dedicated deep cycle battery for your trolling motor.
How much reserve capacity does the 24M800 have?
The product description and battery label list 135 minutes of reserve capacity at 25 amps, enough to run basic electronics and a bilge pump for several hours.
What charger should I use for the 24M800?
A marine charger with a flooded lead-acid setting at 10A standard and no more than 15A, such as the Pro-Guide 12V 10A 1-Bank Battery Charger.
Will the 24M800 fit my Group 24 battery box?
It measures 10 1/4 x 6 13/16 x 8 7/8 in, a standard Group 24 footprint. Always confirm height and terminal clearance under the lid.
Get 800 CCA Starting Power in a Group 24 Case
When your engine needs strong, dependable starts but your boat only takes a Group 24, the Pro-Guide 24M800 delivers 800 CCA and 1,000 MCA plus 135 minutes of reserve capacity in a 42 lb flooded case. It is backed by a 12-month free replacement warranty and a team that knows marine batteries. The Pro-Guide 24M800 is sold through our dealer network, so call us at 1-800-827-3232 and we will point you to the closest dealer.
Not sure how many cranking amps your engine needs? Call our team at 1-800-827-3232 or browse all lead-acid batteries and battery chargers.
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