How to Charge Trolling Motor Battery without Shore Power?

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I’ve been a boat owner for many years, and I always find myself with the same question every summer: How do I charge my trolling motor battery without shore power? Well, luckily, there are some great options. This post will discuss how to charge your trolling motor battery without shore power in three different ways. We’ll talk about solar panels, using alternators, and fuel cells.

Let’s start with the basics. Before you go on your boat trip, ask yourself these questions:

  • How much energy or amp-hours do you consume during an at-anchor day?
  • What is the capacity of your battery bank in amp-hours?
  • How do you track your battery’s usage?
  • How will you replenish the amp-hours you’ve used at anchor?

How Much Energy Or Amp-Hours Do You Consume During An At-Anchor Day?

At first, you need to think about how much energy you use. How many amp-hours per day do you use? The most important one is refrigeration— a fridge that is 9 meters long can take 40 or 50 amp-hours a day. In the summer, there is not much need for lights, but kids might want to watch a movie, or they might want to use their laptop computer. If you have a freezer or ice maker, it will take another 50 – 100 amp-hours of energy. You also need to consider if you have an oven or microwave because those will take 10 – 30 amp-hours every day.

However, a 12V battery system with no inverter will not allow 110VAC appliances to operate. If you don’t have an inverter, this may be the summer to consider installing one. This will allow you to use many of the appliances which only work with electricity like, for example, your fridge and microwave. But if you do have an inverter installed, remember that it will draw power even when not being used. For instance, if you leave it on overnight, it can draw 24 Ah of battery power, doing nothing.

Here’s an example of how much usage we encounter daily:

  • Grand Banks: 42 – 175 Ah/Day
  • Beneteau: 33 – 85 Ah/Day
  • Ocean Alexander: 48 – 375 Ah/Day
  • Catalina: 36 – 150 Ah/Day
  • Meridian: 580 – 500 Ah/Day
  • Suncruiser: 38 – 225 Ah/Day

What Is The Capacity Of Your Battery Bank In Amp-Hours?

It is a measure of how long it can power your boat. You need to know the size of your battery bank and what kind it is.

This will tell you how much power the bank has. Certain types like AGM and Firefly batteries can go longer without needing recharging, which will help them last longer.

To ensure that you get the most use out of these batteries, don’t let them get too low before recharging them again. Flooded batteries should never go below 50 percent capacity.

Many people don’t know how to get the most out of their batteries for a long time. According to Tohatsu, owners should not let the battery get lower than 50% before recharging it again to help prolong its life.

Flooded batteries should be completely discharged every three months to avoid sulfation – this is where lead sulfate accumulates on the plates and creates a high resistance. This high resistance causes a voltage drop and a lower charging ability of a battery.

Sulfation is a major problem with starting batteries, which are constantly being charged but not going completely dead before recharging again, as opposed to deep cycle batteries that are only discharged down between 20-80 percent.

If you don’t hook your batteries up to a charger periodically, the sulfation will become permanent and cause a voltage drop.

According to Mercury Marine, batteries need to be maintained regularly for optimum performance and durability. Certain chargers have settings that re-energize the battery by cycling it from a full charge down to 70 percent and then back up to 100 percent. This method maintains batteries with high power demands, like engine cranking batteries on larger boats or trolling motor batteries.

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How do you track your battery’s usage?

A battery monitor is a way to know how much of your battery’s power you have left. It works like a gas gauge in your car. There are many types of monitors on the market, but most monitors need to be set for the type of batteries you have.

You can buy them new or used. Some battery monitors are made to fit in a certain space, like on top of the battery. Others can be purchased as an accessory and installed anywhere you need them.

Moreover, a battery monitor is like a fuel gauge and speedometer for your boat battery. Several different brands are on the market, such as Xantrex or Victron. When installing your battery monitor, remember to set what type of batteries you have and how much power they store (like 200 amp-hours).

The Xantrex LinkLite or LinkPro might be preset for lead-acid batteries with 200 amp-hours. But you will probably want to change this setting to match your actual battery capacity so you can get an accurate reading from the battery monitor.

How will you replenish the amp-hours you’ve used at anchor?

You’re at anchor, and you’ve used up all your battery power.

This is a common problem for boat owners, especially if they are out on the water for extended periods. It can be hard to find an electrical outlet or generator that will work with your boat’s charging system.

Here I will discuss 3 ways to replenish your battery power.

  1. How do you charge a deep cycle battery with an alternator?
  2. How to Charge a Trolling Motor Battery with Solar Panels?
  3. How do you charge a deep cycle battery with a fuel cell?

01. How do you charge a deep cycle battery with an alternator?

You can charge your batteries even without shore power. There are two ways to do it. One way is by using an alternator. It works when the engine is working, and it can change the amount of amperage that it gives you depending on how fast the engine is going because it’s a mechanical thing. The other way you can charge your batteries is just with solar or wind power, where there isn’t electricity coming out of the ground like at home or in town.

Alternators are good when the engine is running, but what do you do if you are at anchor or in a boat station without shore power? That means you need to rely on an AC generator. Some boaters even added so many things like freezers and ice-makers that they needed their generator to run most of the time.

In boats, deep cycle batteries are used to power the boat. The alternator can charge the battery, but you shouldn’t connect different batteries in parallel like this. Instead of that, we offer a couple of ways to help the battery:

Using an isolator

The purpose of the isolator is to let the battery charge by itself. It lets you know when they are charged and then switches to both. When you have a boat, both batteries need to be working so that if one goes out, the other can start up your boat. The isolator helps keep them mixed up, so you don’t accidentally use up your engine starting battery when your accessories battery is dead.

Using a device like “pro mariner digital mobile charger 130.”

We connect something called a “pro mariner digital mobile charger 130” between your alternator and batteries. This will help charge your batteries faster. We do this by using a device that forces your alternator to produce its maximum output, reducing the time it takes to charge the battery. But if you use this device, you should not use it for too long because it can damage the alternator and make it stop working.

Solar panels are a good way to run your boat when you are in anchor. You can increase how long you stay there by putting two to four solar panels on the boat. If you use solar panels, then you won’t need to use your generator or engine anymore.

02. How to Charge a Trolling Motor Battery with Solar Panels?

It is possible to attach solar panels to your trolling motor battery pack. Solar panels are small and can be wired directly to the trolling motor battery pack. They do not need an inverter or charge controller. A small 6-watt panel should be able to keep your battery charged when you are not using it. If you have a lot of light, it will help keep the battery charged for longer if you don’t use it much. They run off sunlight so that they won’t work at night or on cloudy days.

At first, you need to know What Solar Panel Size I Need To Charge A Trolling Motor Battery?

What Solar Panel Size Do I Need To Charge A Trolling Motor Battery?

We need to explain some things. By maintaining your boat, we mean the battery is at 100% charge and will keep itself this way with help from the solar panel.

You won’t use your boat much now, so you don’t need a lot of power for it. A 10-watt solar panel is enough for trolling motor batteries like yours.

Moreover, your boat has a very small power requirement. It will need even less power if you have a portable solar panel like the Eco Worthy 10W Solar Panel.

This is enough to keep your trolling motor charged, but it won’t be able to charge your battery if there are other things using electricity in the boat at the same time.

Besides this, you might want to buy a solar panel for your boat. If the power output is more than 12 watts, you should use it and top off the battery. You can also buy a specially designed solar panel for marine batteries, but any regular solar panel will work too.

While we are talking about solar panels, you can also use a small, portable generator. If you have room in your boat for a larger system, it’s unnecessary to put one there if the smaller system will work.

How to Recharge Trolling Motor Batteries with Solar Panels?

Trolling motors use a battery which you can charge with solar power after you are done using it. But most people find this impractical because the size of the solar panel is too small to do it.

You will need a large solar panel to recharge your boat battery. But it can be hard to put a solar panel on your boat because there is no space. It does not mean you cannot charge solar power, but it won’t be easy to find space for the panel.

If you have a lot of space on your boat, one great thing to do is use solar power. Most boats use AGM or lead-acid batteries, and they need to be recharged when the battery level reaches 50%. With a 50% DOD, your solar panel needs to provide 50A or more.

If your battery is at 60% or higher, you will need less power from the solar panel, which can be good because it means less time for your battery to recharge. Talking with someone who owns a boat could help!

But aside from the size of the solar panel, there is another thing you should know. The charging time can be different depending on when you charge it.

If you are done for the day, it might not matter what time your battery is charged because tomorrow will be another day. But charging time does matter in many ways.

When charging your battery, you must leave it on long enough to get a full charge. If you do not, the battery might lose some of its power and not last as long.

What if something comes up while your boat is plugged in? It would be hard to unplug and plug back in again after waiting an hour or two for the charger to finish.

Sometimes, there will be rainstorms where it was bright and sunny just minutes before. This can happen quickly!

If you have solar panels on your boat, then the solar panel will be able to charge the battery faster than if you had just used an average charger.

03. How do you charge a deep cycle battery with a fuel cell?

This is an electric battery that you can use to charge your boat. It uses the gas in the fuel cartridge and converts it into energy without any moving parts, making it very efficient.

The EFOY is not a replacement for a traditional generator because it only works when there isn’t any electricity around.

To make sure that it will work, you need to buy a special battery pack that this machine will charge.

This machine starts automatically when the batteries are low and then turns off when they are full again.

You can also use solar power with this machine because solar has no moving parts and doesn’t make noise or bad things come out of its smoke as most machines do.

Is it possible to use all of these charging sources at the same time?

This is how you can use power from different sources at the same time. The key is that each power source is voltage regulated.

So the power doesn’t go right into the battery; instead, it goes into a charging device that looks at the battery’s voltage level and then brings it up to where it should be.

The charger also regulates the current going to the battery. If multiple power sources are present, it ensures that each has a similar amount of current going into the battery.

There is a way for you to charge your boat while motoring. There are two ways: solar and alternator charging, or the solar, EFOY, and generator charging. Either way, they will not overcharge the battery. They charge it in such a way that is perfect for your battery.

There are many different ways to boat without shore power. You will have to do something different this year so stay safe.


It is important to have a way of charging trolling motor batteries while on the water. If you are in need of power, it will be difficult without shore power or solar panels. Luckily there are many ways that you can charge your battery when away from home! Make sure to consider how much electricity will be needed before investing in an expensive system. You may want to start with something simpler like using another boat’s engine for help. Solar panels are great for trolling motors because they are completely green. They are also very efficient and will not take up much space on your boat. This being said, generators are a great option if you want to have more power. AC adapters are the easiest because no one has to move from their seat.


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