Battery Isolators, Why do I need one?

Did you know battery isolators are for more than adding a secondary battery?

First, let’s break down what a battery isolator is

A battery isolator is a giant relay or mechanical ‘switch’. These are often used in marine or agricultural work to physically disconnect the battery power from the vehicle or device it is hooked to. This is a neater way instead of physically disconnecting the battery from the vehicle. By default, when the battery isolator is not powered on, no energy or voltage can pass through. When a small amount of power is applied to the battery isolator, the power flow is ‘returned’. This is great as a small amperage switch or ignition source can be used to power on the isolator without high current wires needing to be routed elsewhere in the vehicle.

Other forms of basic battery isolator which can be found are a physical switch however the drawback is, you cannot remote mount the switch when it is at the battery.

Now that you have an understanding of the battery isolator, let’s look at different applications for the battery isolator.

Some Common Applications Include

  • Dual battery system
  • Vehicle winch
  • Isolating of primary, secondary, or auxiliary batteries in RV’s and Boats
  • Isolating or switching on and off high powered devices (pumps, electric motors, 12v fridges, etc)

How Do I Wire It?

Wiring up a battery isolator is quite simple. each Stinger Electronics battery isolator has 4 terminals like a basic relay. High current power in, high current power out, chassis ground and low current trigger.

  • High Current Power In
    This terminal is connected to the battery or power source
  • High Current Power Out
    This terminal is connected to the device or vehicle you are wanting to power on
  • Chassis Ground
    This terminal is connected to the vehicle’s ground signal/chassis body if metal.
  • Low Current Trigger
    This terminal is connected to a switched 12-volt power source either via a switch or an ignition source. Whenever this terminal gets power, your turning on the battery isolator.

How Can I Use This For My Secondary Battery?

Using a Stinger battery isolator for your secondary battery is easy. wire up as we mentioned above however the low current trigger, you’re going to use your ignition power source.

When your vehicle is running, both batteries are connected to your alternator or charging circuit resulting in both batteries being charged and power being able to be used. We do recommend having an override switch on your vehicle so you can manually shut the secondary battery off if you need to. When the car is turned off, each battery is separated so you can freely use your secondary battery without flattening your primary battery.

Got any more questions about Stinger Battery Isolators? reach out to us at

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