There are still a lot of boat owners out there who are sticking with lead acid marine batteries. It could be because they’re more affordable, it could be because they’re more generally available, or it could just be because that’s what they’re used to, so they aren’t willing to change just yet.
Granted, lead acid has been the standard for a long time and lead-acid marine batteries probably won’t be going anywhere anytime soon. But at the same time, if you’re considering the relative advantages of different types of boat batteries, lithium is becoming an increasingly viable alternative because of a number of features that make it preferable to lead-acid.
This post will take a closer look at some of the main selling points, and whether lead-acid or lithium is preferable.
Energy Density: Lithium
There’s no question about it; lithium marine batteries have a much higher energy density than lead-acid alternatives.
Energy density, in laymen’s terms, is how much energy a battery can store per unit mass. Lithium is a very light element and consequently lithium batteries can hold a lot more energy than lead-acid batteries.
What this means is more power for longer. Also, lithium batteries will offer full power until they’re almost completely dead, unlike lead-acid batteries, which taper off considerably as they discharge.
This equates to more power (from a comparable lithium battery) for powering marine electronics, high-powered lights, and trolling motors, all of which can consume a lot of power.
Size and Weight: Lithium
Because of its higher energy density, you can pack the same performance into a much smaller, lighter, overall more compact lithium marine battery.
As a result, it is possible to manufacture lithium marine batteries that are much smaller and lighter, and therefore easier to handle, than equivalent lead-acid batteries.
Where this really makes a difference is on small vessels that have small battery compartments, as well as on small vessels that are electric-only, such as rowboats, canoes, and bass boats that are powered by trolling motors.
Weight savings will impact the overall speed and handling of these boats, so a lighter battery pack can make a significant impact.
Lifespan: Lithium
Lithium marine batteries last longer than lead-acid batteries. Naturally, how many cycles the battery will last will depend on operation conditions as well as how the battery is stored, how heavily the battery is used, and how fastidiously you keep the battery charged.
That being said, lithium batteries generally last several thousand charge-discharge cycles, whereas lead-acid marine batteries usually only last a few hundred to a thousand charge-discharge cycles, assuming they are maintained ideally.
The lifespan of lithium marine batteries is one of its main advantages, because it helps to offset the higher upfront price, which will be explored at the end of this article.
Charging Speed: Lithium
Lithium marine batteries, like all lithium batteries, charge very quickly. In this specific case, not only do lithium marine batteries reach a full charge faster than lead-acid, but it is also true that lead-acid batteries taper off once they start to get near full. Once a lead-acid battery gets to about a 70% charge, charging speed will slow down significantly.
Conversely, lithium batteries reach their full charge much more expediently, which is convenient for those that use their boats daily.
Safety: Equivalent
There are some who shy away from lithium batteries because they can experience a condition known as thermal runaway, in which the battery heats up and continues to overheat until it catches fire or explodes.
This can be a concern when using the wrong charger, or with a lithium battery that is not controlled by a BMS, or battery management system, that controls the level of voltage and charge rate, among other things.
All of that being said, a lithium battery system that uses an approved, appropriate charger and which is controlled by a BMS can be a perfectly safe alternative to a lead-acid battery.
On top of that, lead-acid batteries tend to off-gas, which refers to the process by which they release dangerously explosive gasses when charged, which presents an explosion/fire risk when they are charged in enclosed spaces.
Cost: Lead-Acid
It is true that lead-acid batteries are, on the whole, considerably cheaper than lithium boat batteries. That being the case, when you consider the significantly longer lifespan of a lithium marine battery, it actually tends to even out. In fact, if you weigh the cost of frequent lead-acid battery replacements, it can actually, in some instances, make lithium a more economical alternative.
The Simple Truth About Boat Batteries: Lithium Offers a Ton of Advantages
While there are still some relative advantages to conventional lead-acid boat batteries, the scales tip heavily in favor of lithium batteries, and the advantages continue to pile up in favor of lithium as they get more affordable and safer, year by year.
If you have any other questions about the lithium marine batteries we sell here, or their applications, get in touch with us directly and we would be more than happy to help you out.
