True Smart Battery Isolator (SBI)

BSR Isolator

This SBI is the ultra-simple but most technologically advanced method of automatic battery isolation. These units can be installed between parallel batteries to automatically control the charging process of the auxiliary battery while insuring isolation or disconnect during the absence of sufficient voltage preventing the main battery from being discharged through the auxiliary connection. The small size and rugged construction of these units allow for quick simple installation for even the most novice installer. To make things even better this unit is "Dual Sensing" which senses the charge of both batteries. If either battery is receiving a current of 13.4 volts, e.g. a battery charger is connected to the auxiliary battery; the SBI dual battery system will engage and charge both batteries the same as if the engine charging system is providing the voltage.

The dual battery wiring diagram will assist you setting up your vehicles or motor engine dual battery kit. This diagram show the well structured schematic layout that even no engineering or technology background can understand on the flow of procedures for your can instalation.

The advanced technology always insures that the first battery is fully charged (13.4v) before connection is made to the accessory battery. This will eliminate any problems caused by your charging source being too low in amps to charge all batteries at once. If placed in linear sequence between each battery the SBI dual battery setup can provide proper charging for several batteries in a multiple battery setup such as in larger boats that may have 2 or more house batteries.

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DNFA BSR Isolator


12V 140amp SBI with Cut-In:13.4V,

  1. Easy 3 wire connection at the battery. No need to bypass existing alternator wiring.
  2. The True SBI dual battery setup has no voltage drop. Conventional diode isolators incur a minimum of 0.6 volt drop.
  3. Compact size - No large heat sink.
  4. Long lasting makes it extremely price effective


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You can easily see by the picture of battery isolator setup below the unit is designed to withstand moisture with the silicone covered circuit board. Although I would not plan on mounting in a position where it would be permanently submerged it is certainly designed to take all the splashing, dripping, spilling, and other various wet conditions that would come along. Notice also the clearly labeled connection posts and the black common ground lead. To be even more convenient all four side are designed with "knock outs" so that you can easily route your connecting wires in any direction.

Dual battery wiring diagram is design to assist car owner on how to install their battery kit in a fast and convinient situaltion. Make sure that when you install or setup this battery isolator for your car or boat, you have the guidance of the dual battery wiring diagram is in your hand
BSR Isolator


The True Smart Battery Isolator (SBI) allows two batteries to be charged at the same time. When the engine is started and the start battery reaches 13.4 volts and remains there for 10 second, the SBI dual battery isolator engages, allowing two battery banks (start and house) to be charged simultaneously. When the voltage drops below 12.9 volts for 10 seconds or more (eg the engine is stopped), the SBI disengages, effectively isolating the batteries from one another. This system eliminates the possibility of draining the start battery with auxiliary electronics use and protects sensitive electronic equipment powered from the house (2nd) battery from harmful engine start up spikes.


2.66” x 2.66” x 2.11”


  • DC Power: 12V
  • Continuous Current Rate: 140A
  • Intermittent Current Rate: 170A
  • Back-up Current at 12.5V: <=13.0mA
  • Ignition Protection: UL1107/UL1500
  • Operation Temperature Range: -30 to 105°C T


Bsr isolator installation diagram
Dual Battery Wiring Diagram Setup

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