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Make Your Marine Batteries Last Longer with These Tricks

By Matt G. · Updated December 30, 2021 · 5 min read
how to make marine batteries last longer
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It is crucial for a professional angler to keep the electric trolling motor operational for a longer period. A marine battery is an excellent source of power.

It is built to supply steady and stable power for long periods. A deep discharge marine battery is one of the most fundamental components of a fishing vessel.

Having said that, it is also important to make the marine battery last longer without charging it very often.

When you are out there in the ocean, it is difficult to find a power source unless you plan to get back to the shore by the end of the day.

Make Your Marine Batteries Last Longer

Some fishing trips can last for days. Hence, fishermen are known to be miserly with battery use.

See Also: How To Charge Deep Cycle Marine battery

Why Does a Marine Battery Need Extra Care and Attention?

A marine battery is perfect for applications requiring a substantial fraction of energy. Applications like an electric motor, sound system, or even a light bulb do not need a burst on energy on startup.

Needless to say, the total daily power consumption depends on the number of equipment on board. Most anglers fail to track power usage and battery state.

A rechargeable marine battery can easily get ruined, or its performance could get affected when over drained. In a sailboat, several electrical devices might be drawing energy from one or a series of marine batteries.

Starter motor, engine fume fan, lights, and marine radio need uninterrupted and stable power.

Furthermore, factors like fatigue or lack of training can also lead to neglect. It is not uncommon for sailboat owners to take their family on a long fishing trip.

The battery will unquestionably get over drained if a kid forgets to switch off the lights or leave the marine radio on. Hence, the marine battery needs extra care and attention from sailboat operators.

Here are the 6 Easy Ways to Make Your Marine Battery Last Longer

1. Use an Alternator Smart Charger

The primary purpose of an alternator is to keep the battery running, while the equipment in the boat continues to draw power from it.

Today’s smart charging systems are controlled by a powertrain control module (PCM). An alternator smart charger is popularly used to charge car batteries, but it can also be used for refueling marine batteries.

For a sailboat with more power requirements, a Regulated Voltage Control (RVC) system is ideal. It has a PCM and an integrated computer for assistance. It keeps the marine battery charged at an eighty-percent state of charge rate all the time. Hence, there is no possibility of over drain.

2. Check the Health of the Battery Very Often

Checking the health of a battery is not as easy as it may seem. Ideally, this task should be assigned to a certified professional, but it is infeasible to arrange one on a fishing trip.

This is where a Digital Multimeter comes into the picture. When connected to a marine battery, it can reveal vital information about the electrical potential, electrical current, and electrical resistance.

You can get a Digital Multimeter online or in a hardware store for less than $50.

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Performing an open circuit voltage test— at least once a week— would do wonders for your marine battery. The primary purpose of an open circuit voltage test is to determine the battery’s state of charge.

According to the data provided by DoItYourself,

  • 12.73 volts indicates 100 percent charge
  • 12.50 volts indicates 80 percent charge
  • 12.24 volts indicates 60 percent charge
  • 11.96 volts indicates 40 percent charge
  • 11.66 volts indicates 20 percent charge

3. Note Down the Power Requirements of Each Device

Determine battery voltage with a Digital Multimeter as you did when checking battery health. Look for power or current ratings on the nameplate or instruction manual of every device.

Note down the readings in tabular form. Some device manufacturers mention the power ratings on the nameplate or device manual. If you don’t find the power ratings, use the following formula:

Power (W) = Current (A) x Voltage (V)

Further, convert watts to amps using the RapidTables online tool.

4. Minimize Your Power Requirements

To make your marine battery last longer, you must perform an audit of the electrical systems onboard. Have a list, with power ratings mentioned for each device. Now you can begin replacing the high power-consuming appliances with their low power consuming substitutes.

For instance, replacing all the incandescent bulbs with LED (light-emitting diode) lights would be a good start.

Not only the LEDs draw less power, but they last way longer than incandescent bulbs. You can shave off some more energy by replacing an electric water pump with a hand or a foot pump. The less energy the devices consume, the longer the marine battery will last.

5. Install a Solar Panel to Make Your Marine Batteries Last Longer

Self-discharge in a marine battery is another factor that leads to over draining. This phenomenon occurs even when the electrodes are not connected to an external circuit.

If a marine battery is allowed to self-discharge for a few days after unpacking, its performance will unquestionably get affected.

The shelf-life of a marine battery may also get reduced by a significant amount. This problem can be resolved without having to invest in sophisticated electrical equipment.

Simply supplement the battery with energy from a solar panel. A small-sized solar panel will cost you less than $20.

6. Turn Off All the Boat Batteries When Not in Use

Do you turn the battery off when you leave the boat at a marina or a dock-yard? Turing the batteries off before leaving the sailboat would make them last longer.

However, do not turn the charging off, especially if you are occasionally sailing. You don’t want the battery to self-discharge.

Also, make sure that power cords are properly connected. Ideally, you want the power cords to be connected to the electrodes via screws or a similar reliable mechanism. There is always a possibility of the power cord coming loose due to wind or any other external factor.

Make Your Marine Batteries Last Longer Summary

A marine battery does not operate like a typical car battery. It needs way more care and attention. The more efforts you put in the maintenance of it, the longer it lasts.

I hope the information shared in this post helps you implement a better power consumption strategy for your sailboat.

Written by

Matt G.

I'm Matt. I've been paddling and running small boats for the better part of two decades, mostly on lakes and slow rivers, and I do my own maintenance because the alternative is a bill I do not want.

What I write about is the stuff that actually decides whether a day on the water is good: whether a kayak tracks, whether a trolling motor has the thrust for the wind you will actually get, whether a battery lasts the trip, and how to clean a carburettor without pulling the whole thing off the transom.

I am not a marine engineer and I do not pretend to be. Where I have done the job myself I say so, and where I am passing on what worked for someone else I say that instead.

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