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A good battery will serve you for a long time. A bad battery, however, is a health and safety hazard. Even worse, one that’s connected to an electrical unit and is not in use can be a fire hazard. A battery disconnect switch cuts off the connection between your battery and accessories that can drain it. It lowers the chances of your battery malfunctioning and protects it against electrical fires and theft. We’ve assessed the best battery disconnect switches and decided to highlight six that are ideal for different batteries.
Best Battery Disconnect Switch
First up is this disconnect switch by Gama Electronics that features an easy twist/untwist design. It is quite easy to install and performs well in cutting off battery drain. Its plastic top is specially designed to be kind to the fingers if you have to fully unscrew it.
You can use the disconnect switch for the battery of a car, RV, truck, or boat. To disconnect it, simply untwist it. The switch has one great feature: It acts as a deterrent for car theft. By simply unscrewing its cap, you keep your car safe from thieves.
Measures 4.1 x 3.1 x 1.2 inches
Easy-to-follow prompts on the switch
Plastic knob to prevent accidental shock
Continuous amp load of 200A
- BrandGama Electronics
- Weight4.8 ounces
Small enough to fit in your pocket
Solidly built and sturdy
Knob is small and could get lost if totally removed
Disconnect switch is made from zinc alloy and not brass
Male post is too small for negative cable
The Ampper disconnect switch is a great device for machinery or vehicles you don’t use often. Its brass material makes it resistant to rust. It is also corrosion-resistant. The grooves on the side offer a good grip, making it easy to operate even in wet conditions.
The switch works by connecting to the negative terminal and giving it a small turn to isolate the battery from a power source. It is easy to fit and install. The prompts on the black knob are easy to follow and make the task easy—even for a first-time user.
Measures 3.9 x 1.5 x 1.5 inches
Rated current of 125A
Knob’s plastic material makes it safe for handling electricity
Easy no-tool installation
- Weight5.3 ounces
Corrosion- and rust-resistant
Can be used for car, RV, and boat batteries and also electrical equipment
Made of durable, solid brass
125 amperage is limiting
Limited to side post installation
Knob and bolt are a little flimsy
This disconnect switch is one of the smallest. It has a quick-turn handle that quickly cuts off electrical supply to your vehicle’s battery. Its design is also unique as it has a mounting plate.
This switch is ideal for racing cars and setups where a quick disconnect is required. However, it also works in RVs and regular vehicles. The handle is long and makes it easy for you to switch off power. Its red color makes it highly visible.
Measures 5.8 x 5.6 x 5.3 inches
Mounting plate with prompts
Epoxy coat on handle enhances durability
- BrandQuickCar Racing Products
- Weight1.1 pounds
Red and black color scheme is good for visibility
Quick-turn handle makes it easy to use
Design adheres to rules set by racing organizations and sanctioning bodies
No instruction manual
Not very durable
This multi-use battery switch can be used in different applications. Thanks to its box design, you can install multiple switches in areas where multiple batteries are in use and reduce the battery drain on all of them. It comes with an indicator that makes it easy to operate.
Its ignition-protection feature makes it a great fit for water vessels with gasoline systems such as boats. It has a continuous rating of up to 300 amperes and can handle up to 48 volts of direct current. It is highly recommended for boating enthusiasts because of its IP66 waterproof rating.
Measures 3 x 4 x 6 inches
Isolating cover allows wire access from different directions
22mm stud accepts multiple cable terminals
- BrandBlue Sea Systems
- Weight7.2 ounces
Ideal for residential and commercial use
Waterproofed against water jets
Box design allows for multiple mounting options
No mounting screws included
Installation might be a little technical
Internal plastic posts get damaged quickly
This disconnect switch has a great design. It comes with a mounting plate that allows for easy installation. Its design allows it to be used in many vehicles and electrical applications. It is, however, specifically designed for panel-mount applications.
With electrical devices, there is always the risk of short-circuiting. This switch features a rear insulation cover to mitigate that risk. It is also marine-rated, thanks to its waterproof capability. The control knob acts as a security feature. The switch cannot be removed when the knob is in on or off mode. If you want to use it as a security device, turn it counterclockwise to disengage the knob entirely. It also prevents accidental adjusting with a design that requires full focus.
Measures 7 x 4 x 3 inches
Rear insulation cover
- Weight6.4 ounces
Resistant to water
Minimal risk of short-circuiting
Hard to read the on and off labels
No instruction manual
No mounting parts included
The Zoostliss Kill Switch is a simple, well-designed device that will ensure your battery doesn’t get drained. With its quick-turn key, it protects your battery as well as your car. The disconnect switch is easy to operate as its two knobs move smoothly without resistance.
The switch has been designed to last. The brass nuts and washers have a long lifespan and can withstand rust and corrosion. The protective cover that safeguards the keyhole is a plus. It prevents water from getting inside, extending the switch’s lifespan. The Zoostliss Kill Switch is easy to install and comes with an additional key.
Measures 3.1 x 2.6 x 2.6 inches
Handles up to 500 Amperes
Two keys included
Brass nuts and washers
- Weight5.4 ounces
Protective waterproof cover
Rust- and corrosion-resistant
Can’t last for more than five seconds at maximum current (500A)
May need to coat the brass parts to extend their lifespan
Best Battery Disconnect Switch Buying Guide & FAQ
A battery disconnect switch is a piece of equipment that prevents your car’s battery—and other electrical equipment—from getting drained. It is a simple device that is very useful, but shopping for one can be a difficult task if you don’t know what to look for.
Knowing the different features of battery disconnect switches will help you to choose the right one for your needs. In this section, we go into detail about disconnect switches, their top features, and their benefits. We’ll also answer a few of the most-asked questions on battery disconnect switches.
Why Do You Need a Battery Disconnect Switch?
If you frequently drive your car, drive an RV, work with multiple batteries, or operate a boat, you know the frustration a dead battery can cause. You may also be familiar with a battery disconnect switch.
If you live or work in an area where you cannot charge your battery whenever you want, a battery disconnect switch is a very useful device. It prevents battery drain when you’re not using your vehicle and is relatively easy to install.
Car theft cases are on the rise, and it’s important to have peace of mind when you leave your car unattended for long periods of time. Sure, you can invest in a safety system, but you can also make a few quick adjustments to keep your car, RV, or boat safe—like installing a battery disconnect switch.
Disconnecting the battery and leaving with the connector is a great way to make sure your car stays safe even if a criminal gets hold of your keys.
- It prevents battery drain and ensures a battery is ready to use—even after a long time.
- It can function as an anti-theft device in unsafe areas.
- It can help maintain one battery’s power while another is in use.
Types of Battery Disconnect Switches
All battery disconnect switches serve the same purpose, however, they come in different designs. The design of a switch usually determines how and where it can be used. Some switches are only ideal for car batteries while others can be used in a range of applications.
Let’s look at the different types of battery disconnect switches.
- Knife Blade
These battery disconnect switches are quite common. They offer easy installation and are easy to use. They are used when there is little clearance above the battery. They are made in the shape of a knife blade—hence their name.
These switches are installed on top of the battery switch and can operate vertically, horizontally, or with a wingnut. Due to their ease of use, they can be installed on any battery, as long as they have the right amperage.
In an instance where you have two batteries and you need to disconnect both, you can use knife blade disconnect switches. You can use one switch to disconnect one battery and another to preserve the other battery.
These switches use a knob that turns clockwise or anti-clockwise to disconnect or connect the battery. They can be top post or side post switches. They are some of the most effective anti-theft battery disconnect switches as their knobs can be easily removed.
The switches are also easy to install. By simply turning the knob about 45 degrees, you can engage or disengage the switch. The knobs are usually made from plastic, while the other parts are made from brass. The plastic is usually of high quality to withstand the heat that’s emitted by engines. These switches are normally used where space is limited.
- Keyed and Rotary
These are found in boats, RVs, and some cars. They have two key functions: to curb battery drain and theft. They operate using keys or rotary switches. Keyed switches can either have actual keys or plastic keys that can be used to cut off power. Most keys are made of plastic and fit perfectly on the thumb for ease of use.
If your switch uses a real key, it is wise to keep spares to ensure you are not caught unaware if the key you use gets lost. You can attach a metal lanyard to the key to keep it close to the switch if you don’t intend to use the switch as an anti-theft device. Keyed and rotary switches come with a keyhole cover that protects them against water and prolongs their lifespan.
What to Look for When Buying a Battery Disconnect Switch
Battery disconnect switches have many similarities. However, to make sure you choose the best one for your needs, there are features you should look for to differentiate the good ones from the bad. These features dictate the switch’s price, ease of installation, and ease of use. Here’s what to look for when buying a battery disconnect switch.
Different switches can handle different amperage ratings. Be sure to choose a switch with the correct amperage. Most vehicles, especially commercial vehicles, have high-power batteries. It is therefore advisable to pick a battery disconnect switch that can handle high amperage.
In addition, the switch you pick should be able to handle high amperage for a long period. This helps prevent short-circuiting in case a high-power battery passes excessive power through the switch.
Check the amperage rating before buying to know if the switch is suitable for the battery of your vehicle, boat, or RV. Different modes of transportation have different alternators that output varying power levels.
- Ingress Protection (IP) Rating
The weather has a direct impact on the functionality and durability of your battery disconnect switch. Choose a switch with a high IP rating. The rating indicates the level of protection a switch’s housing provides to the internal components. It tells you how resistant the casing is against external conditions such as dust and water.
Select a battery disconnect switch with a tough casing that can withstand heavy rain, heavy impact, and dust—especially if you plan on using it in a boat. Some of the best disconnect switches on the market have a housing made out of hard plastic for enhanced durability.
Battery disconnect switch installation can be done in two ways: top post installation or side post installation. The placement can affect the ease of access, operation, and usage of the switch. With top post battery disconnect switches, the switch is installed above the battery.
Some car owners prefer these switches as they offer easier installation. Side post installation, in some cases, calls for extra housing or a mounting plate. And since some side post battery switches don’t come with an instruction manual or mounting hardware, they tend to be more difficult to install.
If you are planning to use your disconnect switch on different machinery or on different cars, choose a universal one. A switch with a ⅜-inch hole can be installed on most batteries—whether it’s in a boat, UTV, or regular car.
Tips for Buying and Using a Battery Disconnect Switch
When you buy a battery disconnect switch, you want it to serve you for a long time. To that end, it is crucial that you take good care of it to reduce replacement costs.
The good news is that once you install a battery disconnect switch, you don’t have to go to great lengths to ensure it performs optimally. However, it's important to know when to turn the switch on and off as this greatly affects its lifespan.
Always remember to turn off your vehicle before disconnecting the battery. This will prolong the lifespan of the battery, the electrical components, and the disconnect switch.
- Avoid random power cuts or you risk damaging the locking navigation system and other anti-theft features.
- When replacing the battery, disconnect the switch—starting with the negative terminal.
- If you are not sure about installation, consult a professional to avoid system failure.
Best Battery Disconnect Switch FAQ:
Battery disconnect switches are quite easy to use. Most come with an instruction manual to make things easy for users. However, there are common questions most users ask when buying or using them. Most of the questions are related to installation, fitting, and replacement. We answer some of these questions in this section.
Q: How do I connect and disconnect a battery disconnect switch?
A: To connect the switch, disconnect the wire on the negative terminal of your battery. Insert the ⅜-inch hole into the terminal, and then attach the battery wire to the other end. Insert the screws and tighten them securely with a wrench. To disconnect the switch, use a wrench to loosen the nuts, then unplug the switch on the negative side.
Q: Why can’t I connect a battery disconnect switch to the positive terminal of a battery?
A: It’s highly dangerous. What’s more, a normal battery disconnect switch will not fit on the positive terminal. Negative terminals measure approximately ⅜-inch or only slightly bigger. Positive terminals have larger diameters.
Q: Why do batteries drain?
A: Battery drain is caused by the electrical components of the vehicle that use power when the vehicle is not in use. These components include clocks and onboard computer systems.
Our Top Pick
The best of the lot is the Gama Electronics Top Post Battery Master Disconnect Switch. Its 200 -amp rating and ease of use make it a great fit for most vehicles and boats. It is kind to your hands and can help protect your car. Overall, the switch offers great value for your money.