Learn about Lithium

Choosing The Best Battery For Your Fish Finder

Jan 20, 2024

Fishing often involves spending extensive hours on the water in search of fish. To achieve this, a reliable battery to power your fish finder is essential, regardless of your trip's location. Understanding the available options and weighing their pros and cons is crucial in making the right decision. The fish finder battery is a valuable asset capable of powering various devices on your boat, providing peace of mind during your time on the water.

In the following sections, we delve into what a fish finder entails, the diverse ways to power it, and the key factors to consider when selecting the appropriate battery for your device.

Understanding Fish Finders

A fish finder is a device that uses sound energy to locate schools of fish underwater. It can be utilized on boats of various sizes, from larger vessels to smaller crafts like kayaks and canoes. These devices enhance the fishing experience, but the choice of the right battery is pivotal for their optimal functioning. If you're uncertain about the safest and most efficient battery option, continue reading to gain further insight.

Powering Fish Finders

On larger boats, fish finders draw power from the vessel's onboard electrical system, which is connected to the boat's marine battery. Typically, larger boats come equipped with built-in marine batteries, while smaller watercraft, such as kayaks, require an external battery to operate a fish finder.

Traditionally, most boats have utilized 12V lead-acid batteries. However, these have increasingly been replaced by high-performance 12V lithium batteries like the Redodo 12V 100Ah Low Temp lithium battery, which offer a lighter, more energy-dense alternative. Compared to traditional lead-acid batteries, these lithium batteries also provide longer-lasting power, especially crucial for smaller vessels where excess weight can impede performance.

lithium fish finder battery

Choosing the Best Marine Battery

Sealed Lead-Acid

Sealed lead-acid batteries are composed of sulfuric acid, lead sulfate, a water solution, and lead. These deep-cycle batteries are often selected for their initial cost advantages. However, their lower upfront price is offset by the fact that they tend to have a much shorter lifespan and can't be discharged more than 50 percent without sustaining damage. In terms of energy output per kilogram, lead-acid batteries offer significantly less power compared to lithium batteries, which can provide nearly six times as much energy. Moreover, a lead-acid battery can only endure about 400 renewal cycles before needing replacement, impacting long-term cost-effectiveness.


Lithium batteries are becoming popular among boaters due to their longer lifespan and enhanced power capabilities. Lithium iron phosphate batteries (LFP or LiFePo4), such as those used by Redodo, offer a safe option for fish finder batteries. These batteries are environmentally friendly and less prone to thermal runaway or fire, unlike lithium cobalt-based batteries. Additionally, LFP batteries do not contain toxic chemicals like lead-acid batteries.

Although lithium batteries entail a higher initial cost, they can last up to 10 times longer than lead-acid batteries, making them a more economical choice in the long term due to reduced replacement expenses. In addition to being lightweight and durable, lithium batteries charge at a much faster rate, allowing for a quicker return to the water. They can also be discharged between 80 and 100 percent of their capacity without incurring damage.

Criteria for Selecting Your Fish Finder Battery

In addition to your specific energy requirements, several key features and benefits should guide your choice of fish finder battery. These factors include water resistance, longevity, weight, reliability, and low maintenance. When comparing lithium marine batteries to lead-acid, the following are important considerations:

Water Resistance

It's crucial to select a battery designed for marine applications to avoid potential water damage. Using a battery unsuitable for aquatic environments risks battery damage and contamination of the water. Redodo lithium batteries are IP65 certified. The Redodo 12.8V 100Ah Low Temp Cutoff LiFePO4 Battery are built by upgreaded BMS with anti-moisture, anti-Dust and anti-salt fog.

lithium fish finder battery


For extended periods on the water, such as during fishing tournaments, a long-lasting battery is essential to avoid unexpected drain and potential stranding. Larger fish finders typically demand higher energy levels. Lithium-ion batteries, known to last up to 10 times longer than lead-acid, are an ideal choice for sustained energy efficiency.


A compact and lightweight battery is crucial, particularly for small watercraft. Lithium-ion batteries offer an optimal solution by providing more power while weighing approximately one-third less than lead-acid batteries. Their higher energy density frees up essential space on the boat without sacrificing functionality, a particularly crucial advantage for fishing kayaks and small vessels.


Reliable batteries are essential to prevent unforeseen incidents and interruptions during fishing trips. The long-lasting and quick-charging capabilities of lithium batteries make them an ideal choice for prolonged reliable use, even after being drained past 50 percent.

Low Maintenance

A battery requiring minimal oversight allows for greater focus on fishing and outdoor enjoyment. Unlike lead-acid batteries, lithium batteries do not need close monitoring or watering. Lithium batteries, such as Redodo's marine batteries, come equipped with a battery management system (BMS) to automatically safeguard against overcharging or over-discharging, providing peace of mind and allowing for a more enjoyable fishing experience.

Why Are Lithium Batteries the Best Choice for Fish Finders?

Lithium batteries are often considered the best choice for fish finders due to several reasons:

Energy density: Lithium batteries have a higher energy density than other types of batteries, meaning they can store more energy in a smaller and lighter package. This is especially important for fish finders, as they are often used in portable and compact devices.

Longer lifespan: Lithium batteries have a longer lifespan compared to other types of batteries. They can withstand a higher number of charge and discharge cycles before their capacity starts to degrade. This is beneficial for fish finders, as they can be used frequently without worrying about the battery's performance deteriorating quickly.

High voltage stability: Lithium batteries provide a stable voltage throughout their discharge cycle, ensuring consistent power supply to the fish finder. This stability allows the fish finder to operate optimally and accurately detect fish and underwater structures.

Quick charging: Lithium batteries can be charged at a faster rate compared to other battery chemistries. This allows fish finder users to quickly recharge their batteries and get back to using their devices without much downtime.

Low self-discharge rate: Lithium batteries have a very low self-discharge rate, meaning they can hold their charge for a longer period when not in use. This is particularly useful for fish finders that may not be used frequently, as the battery will retain its charge for extended periods.

Overall, the combination of high energy density, longer lifespan, voltage stability, quick charging, and low self-discharge rate makes lithium batteries the preferred choice for fish finders, providing reliable and efficient power for underwater fishing applications.


Lead-Acid Batteries

LiFePO4 Batteries

Energy Density







Shorter lifespan, typically 2-5 years

Longer lifespan, typically 10+ years

Charge/Discharge Cycles

Limited, around 300-500 cycles

High, around 2000-3000 cycles, high quality lithium batteries like Redodo provides 4000+ cycles

Voltage Stability

Voltage drops as the battery discharges

Stable voltage throughout discharge cycle

Self-Discharge Rate


Very low, ≤3% per month

Charging Time

Longer charging time

Fast charging capability

Environmental Impact

Contains hazardous materials (lead and sulfuric acid)

Environmentally friendly, no hazardous materials


Requires periodic maintenance (water level check, etc.)

Virtually maintenance-free


Lower efficiency, higher energy wastage

Higher efficiency, less energy wastage

Temperature Sensitivity

Sensitive to temperature extremes

Less sensitive to temperature variations


Relatively cheaper

Initially more expensive, but cost-effective long-term


Fish Finder Battery Recommended

When choosing a fish finder battery for your boat or kayak, it is important to consider several key factors. The battery should be lightweight, water-resistant, durable, and easily portable to withstand the marine environment.

It is also essential to evaluate the amp-hour rating of the battery and compare it to the power draw of your fish finder. This ensures that the battery can provide sufficient power for consistent operation without draining quickly.

One recommended option is the Redodo 12V 50Ah or 100Ah battery. These batteries offer a good balance of performance, capacity, and reliability suited for marine applications.

How Long Will a 12 Volt Battery Run a Fish Finder?

As for the runtime of a 12-volt battery powering a fish finder, it can vary depending on factors such as the battery's capacity and the power consumption of the fish finder. On average, a fish finder consuming around 2 amps can run for approximately 50 hours on a standard 100Ah battery. However, it's important to avoid discharging the battery beyond 80 to 50% capacity to preserve its longevity.

Does a Fish Finder Need its Own Battery?

While a fish finder can be powered by the same marine battery used for other electronics on a boat, using a dedicated battery for the fish finder can have advantages. It ensures a stable and uninterrupted power supply specifically for the fish finder, especially when other electronics may draw significant power from the main battery. Additionally, a dedicated battery simplifies wiring and power management, making installation and maintenance easier.

Can You Run a Fish Finder on a Deep Cycle Battery?

Yes, a fish finder can be powered by a deep cycle battery. Deep cycle batteries are designed to provide a steady and consistent power supply over extended periods, making them suitable for powering fish finders, trolling motors, and other marine electronics. Their ability to handle deep discharges and recharge efficiently makes them a reliable choice for fish finder applications.