Twin O/B, Three Battery VSR?

Hi Kevin,

I am thinking about buying a VSR Smart Battery Switch system to add to my boat wiring setup.

Right now, I am running two outboard engines and three batteries, one per engine and one house battery – and my batteries are becoming flat and I believe they are not being recharged. The boat is new and the boat wiring is been done by a marine electrician.Boat Wiring Store offers a complete line of custom built battery cables for your boat wiring project

Do you think that a Smart Battery Switch system could solve the problem?



Hi Essa,

The simplest solution to many dead battery problems is to eliminate the need to put a battery selector switch in the BOTH position – which works great for charging batteries when the engine is running, but discharges both when it isn’t.

I would consider the following system from our partners at either EzAcDc or Boat Wiring Store:

  • ON/OFF battery switch for engine battery – PORT Engine, STBD Engine, House – All non-emergency loads are connected through the battery switch. When the switch is off, the battery is essentially disconnected. I would leave my auto-bilge circuit connected to the House battery (or at least the non-switched side of the House battery switch). Turn these switches on while using the boat.
  • ON/OFF battery switch for emergency parallel – This would be connected between the positive posts of your engine batteries. Only turn this switch ON if one of your engine batteries is completely dead. Turn back to OFF when the engine starts.
  • VSR between the Port Engine battery and House battery. This will automatically charge the house battery from the port engine alternator.
  • VSR between the Starboard Engine battery and House battery. This will automatically charge the house battery from the starboard engine alternator.

Hope this helps.

Let me know if you have any questions,