Do I Need A Fuse For My Fish Finder?

Do I Need A Fuse For My Fish Finder

If you are a person who loves fishing then you have already invested in a fish finder or a sounder that helps you to detect fish. We all know that fish finders are extremely handy gadgets to have with you when it comes to fishing. But having a fish finder alone is not enough, you have to amp up your skills. You may be thinking Do I need a fuse for my fish finder?

You know there are times when you need to attach all other accessories to the battery and at some other times, you need to attach your electronics to your fuse box. In the case of fish finders, it is always better to connect them directly with the fuse box. How to wire your fishfinder with a fuse box is another discussion for another day.

But, here are a few things you must remember while connecting your fishfinder to the fuse box. It is always recommended that every power wire should be connected to the fuse box. Your fuse box should be as close to the power source as much as possible. Estimating the load, and the side of the gauge you have to adjust your fuse box accordingly.

Do I Need A Fuse For My Fish Finder?

Well yes! You must attach your fishfinder with a fuse and there are several reasons for it. To connect a fuse with your fish finder is essential because the fuser protects your expensive gadget from damage due to power surges. The second and the most important reason is that a fuse will prevent your boat from catching an electrical fire due to a short circuit or something.

If the power wires are not properly connected to the fuse then any frayed or broken wire can cause a misadventure in the form of electric fire which no one wants. It’s not only about the fish finder, in fact, but you also should never operate any electrical equipment directly with the battery or with an inline fuse.

Do I Need A Fuse For My Fish Finder

On the other hand, it is better to have two discrete pairs of wires that should be attached to the main battery, and then take the aid of a fuse block. Out of two pairs, one should be 8 or 10 gauge. However, the second pair should be comprised of heavy wires.

Why It Is Important To Have A Fuse?

In the worst-case scenario, if your boat is damaged or burned due to an electrical fire. Then, the insurance company will only pay you the insurance money if your fish finder has a fuse installed in it. Or else, they won’t pay you anything.

Do I Need Two In-Line Fuses?

Using two in-line fuses is a phenomenon called “Double fusing.” But the question is under what conditions does a double fuse should use? Does it provide better or increased protection than a single fuse? Though a single fuse is adequate in the phase conductor to provide protections against several damages, a fuse attached to a neutral conductor won’t provide you any protection.

If you employ double fusing in your fishfinder it will protect you from all types of faults. However, if you use only a neutral conductor fuse you won’t be protected against phase to neutral faults, and phase-ground faults (inoperative). By using double fusing your equipment is protected against both normal polarity and reverse polarity.

However, it is not recommended to use two in-line fuses within the same circuit. You can install the properly sized fuse near the depth finder close to the battery, and you won’t need anything else. In the case even the fuse accidentally bows due to the current overflow, the current will stop at the battery, and your equipment will be safe.

You need to know about How to install a fishfinder?

What Size Fuse Do I Need For My Fish Finder?

You may get surprised by the fact that even being heavy equipment fish finders don’t utilize as much power as we think. Most of the traditional models extract 1.5 amps and thereby will need a 3A fuse. On the other hand, more powerful and technical models that are equipped with high-tech features like GPS and chart plotting features may extract a current of 3.5 amps. Hence they need a bigger fuse of 7A.

Note one thing that each product has its own specification, and every product is different from the other so always go for the specifics manual to avoid any accident. Things can go in a worse direction in no time, so to prevent such conditions you have to use a fuse of accurate size for every fish finder. Here is a simple rule of thumb, in order to protect your wires from current overflow always use a fuse 1.1 -1.5 time than the current value of the equipment.

What Happens If You Use The Wrong Fuse?

If you use a wrong fuse let’s say if you use a fuse of a low value (using 1A where 3A is needed) it may work fine, but there are high chances that the fuse will blow when a current overflow will happen.

For example, a fuse on a fish finder may work properly as long as you are using it on a low voltage but as soon as the power demand is increased, the fuse will blow. In other situations, the fuse will blow right away as soon as excess current passes through it than its capacity.

If you use a fuse that is close to the current value of the fish finder, mostly nothing will happen. For example, a fuse of 16 amps is used in the place of 15 amps (a fraction more or less) it will work fine.

In another scenario, if you use a fuse of a very high value then you can face serious consequences. As we know, a fuse is meant to protect the wires, but a fuse of too much value won’t protect the wires from the high current surge. That means the wiring is not protected if a fuse of too much value is used than the required one.

It can result in overheating, which will ultimately lead to a fire. Most fish finders have limited capability to pass surplus current, so using a fuse of higher value will melt the wire.

Can you wire the fish finder directly to the battery?

It is advisable to connect your fish finder directly to the battery. The battery can either be a cranking one or an auxiliary one. It’s not recommended to opt for shortcuts while connecting the fish finder. Connect your fish finder with the power wire into a switch or block panel. Using the correct battery and gauge wire connect your fishfinder to the power wire. This type of connection aids in the prevention of voltage drops that can otherwise lead to performance and power troubles.

Which battery should the fish finder be connected to?

Lithium batteries are the best option to power up your fish finders. As compared to other batteries Lithium (LifePO4) is very lightweight and small. It can also power up your fish finder with constant energy, it delivers its full power without any battery-life issues and hence provides consistent and stable power to your fishfinder.

Can you run a trolling motor and the fish finder on the same battery?

If you wire your fish finder and the trolling motor to the same battery, it is most probable that you face “interference.” It is not preferable to intermingle the electronics with your trolling motors because you will get a lot of screen interference. Most of the batteries need to recharge at certain fishing spots, and if you connect the motor and the finder with the same battery, the working of the fish finder will be compromised.

How many amp-hours do I need for a fish finder?

If you use a 12-volt battery then your fish finder will take almost 1 amp per hour. For the calculation, just multiply the amps in your battery by the time you are going to run it. There are several batteries available, the smaller ones can operate for 7 amp-hours. On the other hand, bigger batteries can operate for 10 amp-hours.

Does Inline Fuse Go Before Or After Switch?

This is the major question that people ask themselves while connecting a fuse to their fish finder. The fuse should be installed after the switch. It is because one has to replace the fuse in case the fuse blows, and not the switch. The switch normally does not need any replacement. In addition to this, placing fuse after the switch limits the current to the fuse only, which aids the switch to not exceeding its current capacity.

Always remember that the power supply must hit the fuse first as soon as it begins to flow in a circuit. Why? It’s pretty obvious if you face a bad situation in which the fuse blows up, it means the current stopped there as soon as the fuse blew. That means the remaining circuit and wires are protected from any kind of damage.

What Size Fuse For Lowrance HDS Live?

Most of the fish finders have all the information available on them. However, for a Lowrance HDS live a fuse of 30 amp means the same thing as the wiring in the equipment, which means it serves no purpose. It means one has to install a fuse higher than 30 A. However, always follow the instructions mentioned by the manufacturer of fishfinders.


It is very essential to know and understand how to install the fuse box with your fish finder, and also it is extremely beneficial if you have connected the fuse box directly to the front of the boat.

It will make it easy for you to connect the wires and the equipment as you don’t have to take the wires around the whole boat. Fishfinder wiring with a fuse is not rocket science, it’s quite easy as long as you understand the proper functioning of the fuse, and know which fuse is good for your fishfinder.

As long as you have an effective crimping tool you can easily perform the job. Make sure to buy and install the appropriate fuse as per the instructions of the manufacturer. Once you have installed the fuse, your fishfinder as well as your boat is safe from any type of power surge or electric fire.

Ricki Cooper

I have been fishing for 11 years. I believe in the famous saying "If fishing is interfering with your business, give up your business".

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