Best Marine Battery Guide 2026: AGM vs. Lithium vs. Flooded — What Boaters Need to Know
Marine
- Sponsor
- OPTIMA Batteries
- Location
- Glendale, WI
Boating may be a year-round activity in some parts of the country, but for much of the United States, December is the depth of winter and as far from the end of the last boating season as it is from the beginning of the next. If you are making plans already to head out on the water in 2026, that may involve replacing or upgrading your boat batteries and we'd like to help. Here's a graph for the TLDR crowd:
The Case for Flooded Lead-Acid Batteries
OPTIMA is owned by Clarios, the largest battery manufacturer in the United States, so even though we only offer AGM and Lithium marine batteries, we know as much about flooded lead-acid marine batteries as anyone out there. With that knowledge, we know there are some instances where flooded lead-acid batteries are the best option for boaters. If you have a tight budget and are just looking to get out on the water, a flooded lead-acid battery is likely to be your most cost-effective option.
Likewise, if you are planning on selling your boat soon, it may not make sense to invest in an upgraded battery (or batteries). Flooded lead-acid batteries are widely available anywhere marine batteries are sold. If you go this route, it might make sense to go for the least expensive battery you can find with the most liberal warranty/return policy.
The Case for AGM Lead-Acid Batteries
OPTIMA BLUETOP AGM batteries can last up to three times as long as a typical flooded lead-acid battery in the same application, so if you plan on holding onto your boat, an incremental investment in AGM batteries will more than pay for itself over time. That logic holds true, whether your boating activities focus on fishing, cruising or tow sports. AGM batteries are also far more resistant to damage from vibration than flooded batteries, whether your boat is bouncing across someone else's wake or bouncing across railroad tracks and potholes on a trailer.
The 99.99% pure virgin lead in OPTIMA BLUETOP AGM batteries and robust cast straps connecting the cells also allow for more efficient current flow, both into and out of the battery. AGM batteries are also widely available at most retailers that sell marine batteries.
The Case for Lithium Batteries
We see some lithium brands claiming up to 15,000 cycles for their batteries. Simple math indicates you could cycle such a battery every day for 40 years and still not reach 15,000 cycles. That doesn't mean lithium batteries only have value most boaters will never realize. Some boat owners, including professional guides, serious tournament anglers and liveaboard boat owners will spend hundreds of days on the water each year and many will significantly discharge their batteries every day.
For those boat owners, an upgrade to lithium batteries makes a lot of sense when they quickly surpass the cycle life of an AGM battery. Lithium batteries are also even more efficient at delivering and accepting current, offering more energy density and faster recharging. Some boaters, like flats fishermen, may also see an added benefit of significant weight reduction from lithium marine batteries, which could help improve their draft in shallow areas.
High-end lithium marine batteries, like OPTIMA's ORANGETOP batteries with HYPERCORE technology, are IP67-rated against water intrusion in up to three feet of water for up to 30 minutes...in case you forget to put in your drain plug. OPTIMA's ORANGETOP batteries also have NMEA 2000 connectivity and a free Bluetooth app that can deliver detailed information about your battery's exact state of charge and charging information. While many lithium marine batteries are only intended for deep-cycle use, OPTIMA's DP120 meets or exceeds Mercury's 2022 specifications for lithium engine starting batteries and can also be used in deep-cycle applications.
Cycle Life Caveats
While some battery brands trying to market batteries are more than willing to offer pie-in-the-sky performance claims that may or may not end up being true, it can be challenging to get any battery manufacturer to offer a specific number when it comes to cycle life, because there can be so many variables on how a battery is cycled. Lead-acid batteries designed for deep-cycle use can be cycled far more than lead-acid batteries designed for engine starting. We provided a general cycle life range that can be applied across multiple brands and formulas as a guideline but it shouldn't be considered gospel when it comes to how many cycles you might be able to get out of your batteries.
Play it Safe!
Safety is OPTIMA's top priority, so all OPTIMA ORANGETOP lithium batteries have been tested and/or certified by independent third parties at both the cell level and battery level to the following applicable standards: UL 1973, UL 2580, UN38.3, IEC 62619 and IEC 63057. We wouldn't recommend considering any lithium battery that hasn't met those essential safety standards. OPTIMA's ORANGETOP Q31M-DC150 deep-cycle marine batteries also have integrated, automatic cell heaters. We know not everyone likes to fish in cold weather, but those who do will tell you integrated cell heaters are a must-have feature that allow you to operate in temperatures well below what typical lithium trolling motor batteries can handle.
If lithium batteries have checked all your boxes up until this point, one final recommendation we'd make is that you find a physical address for any lithium brand you are considering (you can see OPTIMA's physical address here). This will help ensure you are dealing with a legitimate lithium battery brand and not some random person selling lithium batteries out of their apartment or a rented mailbox. History has shown those fly-by-night lithium brands may come and go, often leaving their customers with expensive paperweights in the shape of batteries.
Maximize Your Purchase
Whether you purchase a flooded, AGM or lithium battery, the best thing you can do to maximize battery performance and lifespan is to keep your battery voltage properly maintained whenever possible. We're so confident this is true, we'll add an additional year of free replacement warranty coverage to your OPTIMA battery if you purchase an OPTIMA D1200+ charger from us, when you buy your OPTIMA battery.
| Type | Best For | Price | Cycle Life (50% DoD) |
| Flooded | Budget Conscious | Least Expensive | 300-500 |
| AGM | Most Boating Applications | Moderately Priced | 500-1000 |
| Lithium | Commercial/Pro Anglers/Liveaboard | Most Expensive | 2000-5000 |
OPTIMA is owned by Clarios, the largest battery manufacturer in the United States, so even though we only offer AGM and Lithium marine batteries, we know as much about flooded lead-acid marine batteries as anyone out there. With that knowledge, we know there are some instances where flooded lead-acid batteries are the best option for boaters. If you have a tight budget and are just looking to get out on the water, a flooded lead-acid battery is likely to be your most cost-effective option.
Likewise, if you are planning on selling your boat soon, it may not make sense to invest in an upgraded battery (or batteries). Flooded lead-acid batteries are widely available anywhere marine batteries are sold. If you go this route, it might make sense to go for the least expensive battery you can find with the most liberal warranty/return policy.
The Case for AGM Lead-Acid Batteries
OPTIMA BLUETOP AGM batteries can last up to three times as long as a typical flooded lead-acid battery in the same application, so if you plan on holding onto your boat, an incremental investment in AGM batteries will more than pay for itself over time. That logic holds true, whether your boating activities focus on fishing, cruising or tow sports. AGM batteries are also far more resistant to damage from vibration than flooded batteries, whether your boat is bouncing across someone else's wake or bouncing across railroad tracks and potholes on a trailer.
The 99.99% pure virgin lead in OPTIMA BLUETOP AGM batteries and robust cast straps connecting the cells also allow for more efficient current flow, both into and out of the battery. AGM batteries are also widely available at most retailers that sell marine batteries.
The Case for Lithium Batteries
We see some lithium brands claiming up to 15,000 cycles for their batteries. Simple math indicates you could cycle such a battery every day for 40 years and still not reach 15,000 cycles. That doesn't mean lithium batteries only have value most boaters will never realize. Some boat owners, including professional guides, serious tournament anglers and liveaboard boat owners will spend hundreds of days on the water each year and many will significantly discharge their batteries every day.
For those boat owners, an upgrade to lithium batteries makes a lot of sense when they quickly surpass the cycle life of an AGM battery. Lithium batteries are also even more efficient at delivering and accepting current, offering more energy density and faster recharging. Some boaters, like flats fishermen, may also see an added benefit of significant weight reduction from lithium marine batteries, which could help improve their draft in shallow areas.
High-end lithium marine batteries, like OPTIMA's ORANGETOP batteries with HYPERCORE technology, are IP67-rated against water intrusion in up to three feet of water for up to 30 minutes...in case you forget to put in your drain plug. OPTIMA's ORANGETOP batteries also have NMEA 2000 connectivity and a free Bluetooth app that can deliver detailed information about your battery's exact state of charge and charging information. While many lithium marine batteries are only intended for deep-cycle use, OPTIMA's DP120 meets or exceeds Mercury's 2022 specifications for lithium engine starting batteries and can also be used in deep-cycle applications.
Cycle Life Caveats
While some battery brands trying to market batteries are more than willing to offer pie-in-the-sky performance claims that may or may not end up being true, it can be challenging to get any battery manufacturer to offer a specific number when it comes to cycle life, because there can be so many variables on how a battery is cycled. Lead-acid batteries designed for deep-cycle use can be cycled far more than lead-acid batteries designed for engine starting. We provided a general cycle life range that can be applied across multiple brands and formulas as a guideline but it shouldn't be considered gospel when it comes to how many cycles you might be able to get out of your batteries.
Play it Safe!
Safety is OPTIMA's top priority, so all OPTIMA ORANGETOP lithium batteries have been tested and/or certified by independent third parties at both the cell level and battery level to the following applicable standards: UL 1973, UL 2580, UN38.3, IEC 62619 and IEC 63057. We wouldn't recommend considering any lithium battery that hasn't met those essential safety standards. OPTIMA's ORANGETOP Q31M-DC150 deep-cycle marine batteries also have integrated, automatic cell heaters. We know not everyone likes to fish in cold weather, but those who do will tell you integrated cell heaters are a must-have feature that allow you to operate in temperatures well below what typical lithium trolling motor batteries can handle.
If lithium batteries have checked all your boxes up until this point, one final recommendation we'd make is that you find a physical address for any lithium brand you are considering (you can see OPTIMA's physical address here). This will help ensure you are dealing with a legitimate lithium battery brand and not some random person selling lithium batteries out of their apartment or a rented mailbox. History has shown those fly-by-night lithium brands may come and go, often leaving their customers with expensive paperweights in the shape of batteries.
Maximize Your Purchase
Whether you purchase a flooded, AGM or lithium battery, the best thing you can do to maximize battery performance and lifespan is to keep your battery voltage properly maintained whenever possible. We're so confident this is true, we'll add an additional year of free replacement warranty coverage to your OPTIMA battery if you purchase an OPTIMA D1200+ charger from us, when you buy your OPTIMA battery.