Simple! How to Keep Boat Batteries Charged

Published on: April 2, 2022
Written by Liam Jaxon / Fact-checked by David Rowan

Are you worried about your boat battery’s charge? They don’t last a long time. Don’t worry here you are in the right place. We gather all the information on making your batteries have a long life and keeping charging for a long time.

how to keep boat batteries charged

So, keep with us and enjoy the reading journey to know “ how to keep boat batteries charged”. We hope you are not disappointed. And please give feedback on your experience. 

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Generally, the boat batteries last the longest life and charge the fastest if charged in individual phases. That we recommended as the ideal charge curve. Have to remember the precise voltages for batteries is divided into two caveats: 

1) The gel batteries are charged at lower and different voltages. (flooded-type and AGM batteries);

2) The voltage condition is dependent on temperature.

This makes it tough to recommend appropriate charging voltages. Because they vary according to the battery’s temperature. Most of the users operate the boats in temperatures between 50°F to 90°F.

You should already know about the higher temperatures required into lower voltages and the lowest temperatures required into higher voltages. Read below and know how to keep boat batteries charged.

What Size Boat Battery Charger Do You Need?

The size of your charger depends on your boat battery types and size. Most of the boats spend their week at a dock constantly hooking up. That’s for shore power requiring the smaller chargers. You need enough capacity to run the serial loads on your battery system.

As like DC refrigeration and enough power to float charge in your batteries. Most of the amperage that the batteries can accept over the bulk phase of the charging cycle change depending on the battery. For example- 

  • When the flooded batteries can accept up to 25 percent of the C charge rate. 
  • On the other hand, the gel batteries have a high acceptance rate of up to 30 percent. 
  • And the AGM batteries accept up to 40 percent of the C charging amp.

How Long Does It Take to Charge Itself?

The cause of overcharging a lot of batteries is going to fail. It will happen when the chargers basically cook the battery until. And it can not hold the charge for a longer time if you are busy and need to charge your battery.

Then you have to choose a 2 amp charger for charging your battery, and you can leave for your other job. If you choose a charger within 10, 12, or 15 amp, It risks cooking and causing it to fail. Additionally, you do not need your battery charger hooked up to your batteries at all times. The ideal use your charger for a day or two. And leave it unhooked for up to a week.

How to Make the Boat Batteries Longer Live?

For getting a longer battery life, you have to take proper maintenance. According to Dr. Jason Halfen, the perfect way to maintain your boat batteries is to store them over a long time. So by following those tricks, you can make your boat batteries have a longer life.

1. Marine battery Monitor state

Good battery management is the main factor in their longevity. The monitoring battery’s solutions can monitor up to 6 battery banks, 14 banks, and 20 banks in independent current sensors. The pico is prepared with a Wi-Fi module to communicate with the application. The application is allowed to access live data and can analyze historical data.

2. Calculate Daily Used Power

It is one of the most important components for ensuring your battery life. For small batteries, you will take out too much charge every day. Daily power use can deliver allotment data by multiplying the current Amps. Ideally, the batteries sized should be as their amp hour rating is 3 times larger than its daily electrical consumption.

3. Minimize your Power Requirements 

For the batteries to extend a longer life, it is one of the cheapest and easiest ways. It is so simple and does not leave lights on without cause. If you change your light with low-energy LED bulbs, it can reduce consumption. And it also gives a longer service. Similarly, a pair of frozen water bottles placed in the fridge at the beginning of each trip will decrease the power to keep the contents cool.

4. Added a Solar Panel

When you don’t use your boat, it can also lose its charge based on battery type. They have a self-discharge rate of almost 1-3 percent per month. However, a cheap solar panel will help to prolong their life. This is real even on the northern side in the summer. That will be helpful for the long daylight cloudy conditions. When the boat is out on a mooring, then shore power is not accessed. But the batteries will fully charge up at the start of each weekend.

5. Fit a Decent Mains Charger

If you frequently use your boat, then plugging into their power supply is the easiest way to reduce the batteries’ drain. A quality 3 or 4 stage charger will make sure the batteries are 100 percent charged when you leave the next morning, equally, for your boats with access to shore power on the moorings, a charger that can be left constantly connected. And will ensure that the batteries are permanently pampered.

6. A Smart Alternator Charger Add

With a 75Ah alternator, you may gain 50Ah of charge immediately after beginning the engine. But after just 15 minutes of engine running, that figure will halve.

A smart charging regulator fulfills the charging rate closely to the initial-figure. This system has the advantage that it will charge batteries to 95 percent of capacity.

7. Fitted a Large Alternator

Are you not able to put a sufficient charge into your battery bank? This way is the most cost-effective to increase the amount of charge the batteries receive. Several aftermarket suppliers offer alternators a larger output that will fit a variety of boat engines.

8. A Wind Turbine Or Hydro-Generator

15 years ago, wind turbines were very popular with the people. It became a very cheaper and more efficient way to put an extra charge into your boat batteries. Although it’s important to know about their disadvantages before opting to fit one, several holders value their wind generators.

Hydro generators, whether are the most traditional or efficient newer transom-mounted types. Therefore, they can be perfect for those that sail longer distances. Of course, they won’t help to charge the batteries while the boat is in port.

What Kind of Charger Should Be Used to Keep Boat Batteries Charged?

It depends on the type of battery used in the boat. Generally, a marine or deep-cycle charger is best suited for charging boat batteries. These chargers can provide a slow, steady charge to ensure long battery life and reduce the risk of overcharging.

How Can You Avoid Battery Problems?

  • Secure your boat battery with a good battery tray. Be careful, don’t put the battery almost in rough water.
  • Continuously check your batteries’ terminal connections to ensure they are free of corrosion. 
  • Before off-season storage, you should completely charge your batteries. And disconnect the terminals. Now, nothing can draw your battery down.
  • Install a cover over the top of the positive battery terminal.

What is a 4 Bank Or 3- Bank Battery Charger?

GEN4 is onboard for charging and keeping up a four 12-volt boat battery charger. It is a more deep-cycle battery. It is also one of the most developed charging features and life span battery. A 40 Amp, 4-bank, or 10 Amps in every bank to the onboard battery charger.

A three-bank battery charger is the most common charger used by anglers with a smaller boat by a trolling motor. This battery charger has three banks for charging at one time the multiple batteries. Three-bank battery chargers are generally designed to allow each battery to charge in the full capacity at the same time.


If you take proper maintenance of your boat charge, it will be longevity. For getting higher performance, it services your battery all the time or regularly. Also, store it in a dry, clean, and controlled temperature place.

Must use a hydrometer and a volt-meter to test lead-acid wet cell batteries. If you are concerned with jostling, that will damage the cells for a stable AGM battery. During trolling, minimize the drain to keep your speed lower. Also steady and staying in calm waters as possible.

For understanding your boat’s power consumption, you need to take proper care of your boat battery and exercise discretion. While on the water, you will have to enjoy a hassle-free performance from your trolling motor.

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About This Writer

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Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

Hi, I am responsible for the 'Homeowners Power Solutions' category. My name is Liam Jaxon and a licensed technician with 7 years of experience in vehicle batteries, electrical gadgets, and home appliances. My working experience in different residential & light commercial electrical sectors and the automobile industry helped to acquire vast knowledge in this industry.

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