Matson MA98504 - Dual Battery Kit with Override Switch and 140Amp VSR


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Complete dual battery kit for easy DIY installation.
All components and full installation manual included. Add the battery of your choice and you can easily add a high quality dual battery set up to your 4wd or truck.


Weight (kg): 2.5
Warranty: 1 year

Additional Information


  • Automatically isolates the starting battery from the auxiliary battery
  • Suitable for 4X4, Marine, Truck, Caravan & camping applications
  • No need to modify vehicle wiring
  • Kit contains all components required to complete the job (except battery)
  • Voltage sensitive relay rated at 140 amps
  • Proven reliability over many years
  • Override switch to parallel starting and auxiliary battery (allows starting the engine in case the starting battery fails).


  • Cut in 13.3 Volts
  • Cut out 12.8 Volts
  • 140 Amp rated
  • Dual battery isolator hermetically sealed
  • Full instruction manual included

Download the fitting instructions here (pdf).

How the dual battery kit works

The Matson Dual Battery Kit is designed to allow the 4WD, caravan and boating enthusiast to run a second battery for all those power hungry outdoor accessories, without risking power drain from the vehicle's starting battery. When installed in accordance with directions, the voltage sensitive relay will stay open when the engine is started, isolating the starting battery, until the charge rate reaches 13.3 volts at which time the voltage sensitive relay closes allowing both batteries to be charged. When the voltage of the cranking battery drops to 12.8 volts the relay isolates the two batteries leaving the cranking battery fully charged while the auxiliary battery continues to power the accessories.

The next time the vehicle's engine is running, the starting battery is charged back up to 13.3 volts, at which time the VSR redirects the charge back to the auxiliary battery.

Manufacturer Information