True® Dual Smart Battery Isolator (SBI)

(11 customer reviews)


This 12V True® Smart Battery Isolator is a ultra-simple and most technologically advanced method of the automatic battery isolation system.

  • Guaranteed no volt drop
  • Lifetime flat fee replacement.
  • Compact, durable and smarter.
  • Maintenance Free
  • Free Shipping
  • Visit Shipping, return and terms policies
SKU: TSDBK1001 Categories: ,



  • 12V 140amp Smart Battery Isolator with Cut-In: 13.4V
  • Cut-Out: 12.9V
  1.  Easy-3 wire connection at the battery. This True® smart isolator does not need to bypass existing alternator wiring.
  2. True® dual smart battery isolator setup has no volt drop. Conventional diode isolators incur a minimum of 0.6-volt drop.
  3. Compact size – No large heat sink.
  4. This smart isolator is a cost-effective solution.
  5. Dual Sensing Technology
  6. Official True® retailer.
  7. Lifetime flat fee replacement.
  8. Compact, durable and smarter.
  9. Anti-vibration and corrosive proof

*The True® Smart Battery Isolator (SBI) is programmed with a 10-second delay before engaging or disengaging.

  • 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
  • Delivery: USPS first class or priority mail

True® Dual battery Smart isolator can be installed between batteries with a common ground to automatically control the charging process to the batteries but continue to provide isolation of them when a charging source is unavailable. The small size and rugged construction of these units allow for quick simple installation for even the most novice Driver.

True® Smart dual battery isolator sensing features

To make things even better this unit is “Dual Sensing” which senses the charge of both batteries. If either battery is receiving a charge, e.g. a battery charger is connected to the auxiliary battery; the SBI True® battery isolator system kit will engage and charge both batteries.

The advanced technology always ensures that the first battery is fully charged (13.4v) before the connection is made to the second battery. This prevents problems that may result from your charging source being too low in amps to charge all batteries at once. If placed in linear sequence between each battery the  True® 12v smart dual battery isolator can provide proper charging for several batteries in multiple battery setups such as in larger boats that may have 2 or more house batteries.

You can easily see by the picture of 12v True® dual smart battery isolator 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 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 sides are designed with “knockouts” so that you can easily route your connecting wires in any direction.


Electronic Specifications

 True part number  Rating Voltage  Continuous Current  Intermittent Current  Cut in voltage Cut out voltage  Ignition Protection
IP-DS14012.913.4 12V  140 Amp  170 Amp  13.4 V* 12.9 V* UL1107/UL1500

LED Indications

On: Isolator engaged
Off: Isolator disengaged
2.7(L) x 2.7(W) x 1.95(H) inches


(These videos are not endorsed or represented as an “Official Installation video” by True Amalgamated and True Amalgamated accepts no responsibility for its content. It is produced by the end-user as stated. Follow entirely at your own risk.)

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Additional information



11 reviews for True® Dual Smart Battery Isolator (SBI)

  1. Ted

    5.0 out of 5 stars
    Save your towing vehicle’s battery

    Verified Purchase
    This is not your father’s isolator. This is a smart device which senses both batteries and if either one is receiving a charge, it will enable charging of both.
    Most importantly if you park your tow vehicle and shut down the motor so it is no longer providing current to charge both batteries, it will isolate them and protect your starting battery. Without the isolation, devices in your boat/camper can discharge both batteries and you will be unable to start in the morning when you are ready to get the day going. I have had this happen to me.

    This is not just an old fashioned isolator which uses diodes and actually reduces the amount of current available to charge the batteries. That is why those older style isolators have such a large heat sink (the finned aluminum base) to dissipate the wasted energy. Notice that this isolator does not have, and does not require, a heat sink because it uses a relay that it closes or opens and has no energy loss due to internal resistance.

    So yes, it is a little more costly than the older “diode” isolators, but it will do a much better job protecting your batteries!

  2. Amazon Customer

    4.0 out of 5 stars

    This battery sensor works great. I know some people have an issue with …

    Verified Purchase
    This battery sensor works great. I know some people have an issue with the led. What this voltage sensing relay is actually doing is parrelling your start battery with your house batteries. Whenever the voltage is above 12.8. The led stays on indicating that all 3 batteries are in parallel until it drops below 12.8 volts and once it’s off the led won’t come back in until it senses 13.7 volts on the start battery, so essentially you have a third battery until 12.8 volts. I kinda like the led. I have the vsr stored under my dash on the drivers side. It looks like their is an alarm installed if someone looks in at night in the vehicle. Just my 2 cents. I gave it four stars since the instructions are vague and that the Company who sells it couldn’t even really pinpoint what the led is doing. Also make sure your put a fuse at the start battery and house battery. The instructions don’t say to do this, but that isn’t how I roll.

  3. Ericofcourse

    5.0 out of 5 stars
    Not cheap because it’s not cheap.

    Verified Purchase
    I am using this in a Ford e350 van, converted to a camper, to maintain the truck battery under the hood and maintain 2 deep cell marine batteries in the back, which i run a fridge/micro, etc. with using a 1500 watt inverter. I was told by many old school camper guys this setup wouldn’t work, but it works great! The VSR is small and lightweight, and simple to hookup and use. It has one simple LED light letting you know where it’s sending voltage. Proper gauge wire is imperative, i have 6 gauge run to all batteries, with a 150 amp ANL fuse, and have had no trouble at all with this unit. I returned a much larger, heat synced Northern tool unit after i saw the difference in size. This one is great under the hood of a van or any tight space.
    Word of note: I did have to trim some of the plastic away where my wires run in and out of the unit. It’s 2 pieces and you have to trim away part of the cover if you’re using proper gauge wire to get it to sit on the base correctly. This will make sense when you see the unit in person, and it’s pretty obvious the manufacturer intended for you to cut or drill depending on your application.

  4. Harry KG5JX

    5.0 out of 5 stars

    Vital to keep that starter battery from being discharged.
    September 8, 2017
    Verified Purchase
    I use this to charge the deep cycle battery inside my van. I run various items off that single battery without discharging the starter batter. It waits until the main car battery charges up to about 13.2 volts, then begins charging the deep cycle battery — safe and neat!

  5. Cart T

    Verified Purchase
    Works great for my auxiliary battery in my Jeep Liberty.
    Reviewed in the United States on October 5, 2020

    Easy setup. Hasn’t failed me yet. Failure would be running down my primary battery. So, it isolates as it should. Installation was not difficult, even for a woman with only basic knowledge of electricity. The star I deducted is for the price. Must have a considerable mark-up on it.

  6. Mike Mayeshiba

    Verified Purchase
    Reviewed in the United States on August 11, 2020

    Installed in my 185 bowrider sea ray. in less than 2 hours. Have had it installed for about 3 months now and it seems to be running great. Sit out on the sand bar for hours and hours with confidence and not having to worry if my boat will start.

  7. Ruel Bennet

    It works as it should be. The design was a bit better than my expectations. Thank you, True. It solved my month-old problem.

  8. Nick Young

    Im totally satisfied with my purchase. This is a good and durable battery isolator. Like always, TrueAm processed and shipped my order fast.

  9. Carl Lawrence

    The product works just as advertised and suits my purposes perfectly. My second battery drives a heavy-duty wench, fog lights, and stereo system, and the smart battery isolator has been keeping it well charged. It was easy and quick to install.

  10. Corine White

    Working perfectly. It isolates my system battery from my starting battery. I’m still running my stock 130-amp alternator, so this 140-amp isolator did the trick.

  11. Joey Amber

    To run my audio without running out of power, I need this battery relay. Considering how much current the hot air conditioner is drawing right now, it permits two batteries to run and charge automatically.

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