• Hardkorr Voltage Sensitive Relay Kit for Battery Box - 12V Dual Battery Charging Kit
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Hardkorr - HKPBATTVSR

Hardkorr Voltage Sensitive Relay Kit for Battery Box - 12V Dual Battery Charging Kit

Ideal for 4WD owners, campers and tourers running a portable battery box who want a simple and automatic way to charge their auxiliary battery while driving.

$34.95 AUD
$34.95 AUD
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  • Fast Australia-wide shipping
  • Trusted by Australian 4WD and touring enthusiasts
  • Reliable stock and competitive pricing
  • Expert advice from the Battery Force team
  • Built for harsh Australian conditions

The Hardkorr Voltage Sensitive Relay (VSR) Kit for Battery Box is a simple and reliable solution for charging your auxiliary battery while driving. Designed specifically for use with battery box setups, this 12V dual battery charging kit automatically manages power flow between your start battery and auxiliary battery, protecting your vehicle while keeping your secondary battery charged.

Using intelligent voltage sensing technology, the relay connects the auxiliary battery for charging once the vehicle’s start battery reaches a safe voltage. When the engine is turned off and voltage drops, it automatically isolates the batteries - preventing your start battery from being drained by fridges, lights or camping accessories.

Ideal for touring, camping and 4WD setups across Australia, this VSR kit provides a cost-effective alternative to DC-DC chargers for compatible systems. It’s straightforward to install and designed for dependable performance in harsh outback and off-road environments.

If you're running a portable battery box in your canopy, trailer or caravan, this Hardkorr VSR kit makes dual battery charging simple and automatic.

Available Australia-wide from Battery Force with fast dispatch and expert advice.

Key Features

  • Automatic voltage sensitive relay (VSR) operation
  • Charges auxiliary battery while driving
  • Protects start battery from discharge
  • Designed for battery box dual battery setups
  • Simple and reliable alternative to DC-DC charging (where suitable)
  • Heavy-duty cabling and components
  • Ideal for 12V touring and camping systems
  • Easy installation for 4WDs, caravans and trailers

Specifications

Product Type Voltage Sensitive Relay Kit
System Voltage 12V DC
Application Dual battery charging (battery box setups)
Operation Automatic voltage sensing & isolation
Installation Hardwired kit
Compatibility Suitable for vehicles with traditional alternators
Use Case 4WD, touring, camping, trailers, caravans

How does a voltage sensitive relay work?

A VSR monitors your vehicle’s start battery voltage. When it reaches a safe charging level, it connects the auxiliary battery for charging. When voltage drops, it automatically isolates the batteries to protect your start battery.

Is this better than a DC-DC charger?

For vehicles with traditional alternators and shorter cable runs, a VSR can be a simple and cost-effective solution. Vehicles with smart alternators may require a DC-DC charger instead.

Can I use this with a battery box in my canopy or trailer?

Yes. This kit is specifically suited to battery box setups commonly used in canopies, trailers and touring vehicles.

Will it flatten my start battery?

No. The relay automatically disconnects when voltage drops, protecting your start battery from discharge.

Is professional installation required for this VSR?

Installation is straightforward for experienced installers, but professional fitting is recommended to ensure correct wiring and safe operation.

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