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Redarc Smart Start Battery Isolator with Wiring Kit - 12 Volt - 100 Amp
Redarc

Redarc Smart Start Battery Isolator with Wiring Kit - 12 Volt - 100 Amp

Part Number: 331-SBI12KIT
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$269.00
Retail:$295.90
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This 100-amp dual-battery isolator pulls power from your start battery to charge your auxiliary battery. Isolator switches off to prevent dead battery if start battery voltage drops too low. Compact design for versatile mounting. Wiring included. 1-800-940-8924 to order Redarc battery charger part number 331-SBI12KIT or order online at etrailer.com. Free expert support on all Redarc products. Great prices and Fastest Shipping for Redarc Smart Start Battery Isolator with Wiring Kit - 12 Volt - 100 Amp. Battery Charger reviews from real customers.
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  • Reviews (24)
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Redarc Battery Charger - 331-SBI12KIT

  • Battery Isolators
  • 12V
  • Vehicle Battery to Auxiliary Battery
  • Redarc

This 100-amp dual-battery isolator pulls power from your start battery to charge your auxiliary battery. Isolator switches off to prevent dead battery if start battery voltage drops too low. Compact design for versatile mounting. Wiring included.


Features:

  • Battery isolator protects start battery from auxiliary drain in multiple battery setups
    • Transfers charge from start battery to auxiliary battery once start battery gains charge from alternator
    • Stops charge transfer if start battery voltage drops too low, preventing excessive discharge
  • Override wire allows for emergency starts and simple fault detection
    • Attach to a switch (sold separately) to manually reverse charge and jump-start a dead start battery
    • Connect to an LED (not included) that can be mounted in your cab for easy viewing of diagnostics
  • Silver contact points ensure long life and corrosion resistance
  • Compact design allows for versatile installation
    • Mount the isolator in a convenient location near the start battery
  • Plug-and-play wiring kit includes:
    • (2) 7-3/4" Long and (2) 70" long positive battery cables
    • 29-1/2" Long ground wire
    • (2) 60-Amp fuses
    • (2) Fuse holders with mounting nuts
    • (2) Battery terminals with protectors
  • Made in Australia


Specs:

  • Application: vehicles with standard or temperature-compensating alternators
  • Maximum continuous current: 100 amps
    • Standby current: less than 5 mA
  • Output connection: 12V DC
  • Overall dimensions: 3-1/8" long x 2-15/16" wide x 2-1/2" tall
  • Wire gauge: 6
  • 2-Year warranty


With this dual-battery isolator, you can transfer power from your start battery to an auxiliary battery without draining your start battery. As long as your vehicle is on and the alternator is supplying power to the start battery, the Smart Start will transfer some of that power to your auxiliary battery. When your vehicle is shut off, the isolator will separate its connection and stop pulling power. This ensures that your start battery is protected so that no matter how weak your auxiliary battery becomes, your start battery won't be left flat. As a result, you can venture out without the fear of running into a dead battery.


Parallel Charging for Optimal Functioning

REDARC Smart Start Dual Sensing Battery Isolator Parallel Charging Setup Diagram

The Smart Start connects in-line between your start battery and the auxiliary battery. This way it can pull the charge directly from the battery instead of pulling from an outside source, like your vehicle's alternator. This method of charging is called parallel charging.


REDARC Smart Start Dual Sensing Battery Isolator Priority Charging Setup Diagram

Most other battery isolators on the market use priority charging. In a typical priority charging setup, the alternator provides charge to either the start battery or the auxiliary battery, but not to both simultaneously. This can leave both batteries underpowered. With parallel charging, the power is drawn directly from the start battery, which removes stress on the alternator because it doesn't have to manage both batteries separately. This streamline connection of the Smart Start to the start battery also prevents potentially damaging voltage surges that can occur when a priority charger switches over between batteries.


Additional Features

The blue override wire attached to the Smart Start allows for additional features, like the Start Assist function. This function allows you to jump-start a dead start battery using the auxiliary battery. Just connect the blue wire to a push-button switch (sold separately) to create a bridge of power from the auxiliary battery to your dead battery. Great for those mornings when you leave the radio on too long or forget to close the vehicle door.


You can also connect the blue wire to an LED (not included) to create an in-cab fault indicator. There is an internal LED on the unit itself that provides fault detection. This system communicates by causing the LED to flash a certain number of times to indicate errors. For example, 2 flashes signals over-voltage, and 3 flashes signals a voltage drop or excessive current draw fault. By connecting an additional LED to the blue wire, and running that up to your cab, you can more quickly assess these faults than if you had to peer into your engine compartment to see the light on the unit itself.


For assistance in wiring the Smart Start to include these optional features, please refer to the diagrams below:


Redarc Smart Start Battery Isolator Optional Wiring

Compact Design for Versatile Mounting

Mount the battery isolator in a location near your vehicle's start battery. The compact design of the unit allows you to have a good deal of flexibility when selecting a mounting location. A couple of places to consider would be in front of the radiator or behind the headlight assembly. You will need to make sure that the location you choose is not exposed directly to engine heat.


Place the included fuses into the fuse holders and secure one end of each positive (red) cable to the studs on the holders. Then connect the cables to the positive terminals on the start and auxiliary batteries. Securely mount the Smart Start unit and use the free ends on the positive cables to attach each battery to one of the terminals on the Smart Start. Properly connect the ground wire, and ensure that all connections are tight.


For assistance in properly wiring the Smart Start, please refer to the diagram below:


Redarc Smart Start Battery Isolator Wiring Diagram



SBI12KIT REDARC Smart Start Battery Isolator w/ Wiring Kit - 12 Volt - 100 Amp

Installation Details 331-SBI12KIT Installation instructions


California residents: click here



Customer Reviews

Redarc Smart Start Battery Isolator with Wiring Kit - 12 Volt - 100 Amp - 331-SBI12KIT

Average Customer Rating:  5.0 out of 5 stars   (24 Customer Reviews)

This 100-amp dual-battery isolator pulls power from your start battery to charge your auxiliary battery. Isolator switches off to prevent dead battery if start battery voltage drops too low. Compact design for versatile mounting. Wiring included.

by:

I use this in my Jeep to keep my second battery for accessories charged and ready. After a year of having it installed I couldn’t be happier with the product. I have spoken with the folks out in Australia at Redarc and find them to be very awesome to speak too.



by:

Wonderful instructions, plenty of wire, and a very good product. Will try and update this review in a year! Thanks for putting the pieces together. All solid quality, 60 amp fuses, and neatly trimmed heavy gauged wire.



by:

It's for my 04 Jeep Wrangler TJ.



by:



by:

Awesome product, easy to install and come with all parts needed to install second battery!!!



by:

I didn’t know this product existed. I don’t know why RV manufactures don’t install these when they build the motor homes. Always a pleasure doing business with e-trailer.



by:

Really like this isolator. Replaced two Cole-Hersey Isolators that failed prematurely in a Class C RV after only 11 and 3 months. Second photo shows Cole-Hersey replaced by Redarc shown in last picture



by:

Outstanding product, satisfying results and top notch quality.



by:

works perfect



by:

I purchased the Redarc 331-SB1212D battery charger during the 2018 Christmas holiday season, it shipped with good efforts from etrailer. It is installed on a 2009 Chevy 5500 diesel powered cab and chassis truck , 2 on-board factory batteries in combination with add on 2 battery auxiliary bank, chassis mounted. I have extra heavy auxiliary power leads wire loom insulated routed with 350 amp Anderson connectors located at the ends , 1 lead to the front bumper , 2 leads to the rear bumper and a small 2/0 lead routed to the cab with 175amp Anderson connector for a 650 watt inverter. This application provides jumpstart service and remote power for dump trailer and 3000watt inverter power . This system has an additional provision to combine all batteries for heavy winching or sub zeros self jumpstart . My installer provided the additional switching to Redarc design specification.








by:

I put this on a 2013 chevy HD 4 wheel drive and it works very well.
I have my main battery went bad and I open the hood and flip the switch and the
accessory battery started my truck. thank you for having good products for us to buy
when we need something,



by:

With a flip of a switch from the drivers set, I'm able to re-charge the coach batteries from the vehicle battery via this Redarc Battery Charger while driving to the next camping adventure.



by:

This bad boy had me at dual sensing, and 200 amps is exactly what I need for my beefy house battery bank. One knock might be a short ground wire, but otherwise great product.



by:

This is a great product. I use it to run my fridge in my Jeep to keep the second battery charged.



by:

I have used these redarcs a couple of times with great success but having this shipped in a very timely fashion from etrailer is fantastic!



by:

Product works as expected and I would recommend it to anybody needing a product like this.



by:

Works great



by:

Got exactly what I needed and very fast.



by:

works prefect



by:

Great product, great service.



by:

works great would but anain



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See what our Experts say about this Redarc Battery Charger

  • Would Redarc Smart Start Battery Isolator Kit Work on 1978 GMC K25 Truck
    While your 1978 GMC truck is a bit older it does use a standard alternator like what the Redarc Smart Start Battery Isolator with Wiring Kit # 331-SBI12KIT was designed to work with so it would work great for you.
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  • Battery Charger Recommendation to Charge Trailer Battery from Alternator and Solar Panel
    The Redarc In-Vehicle BCDC Battery Charger # 331-SBI12KIT that you referenced can manage input current from a solar panel and an alternator as well as 12 volts to 24 volts so you'd be totally fine to use this. You would not be able to reverse the flow of the charge though and go from the battery bank you are charging back to the vehicle. It only allows charging in one direction. I attached a chart that shows how this wires up as well.
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  • Should I Install a Relay To Cut Power To Trailer Battery Charge on 7-Way with Vehicle Off
    The battery charge line circuit is not keyed in many vehicles from the factory meaning it has constant power. If you wish to install a simple isolator then you can do so but a better option is the Redarc Smart Start Battery Isolator with Wiring Kit part # 331-SBI12KIT which actually monitors the status of the start battery and uses that to determine when it should charge the aux battery. It can also pull power from the aux battery to charge the start if something goes wrong. This is a must...
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  • No Power To 12 Volt Pin In Trailer Connector on 2017 Ford F-350
    It doesn't work the way you think it does so that's probably why you think there is an issue. The circuit is usually only powered while traveling down the road and gear shifting takes place. The only way to get around this is to run a power wire of your own from the battery to the trailer connector. We do offer kits for this like the Redarc Smart Start Battery Isolator with Wiring Kit part # 331-SBI12KIT which is a bit better than the factory system in that it can sense trailer battery...
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  • What Gauge Wire Should be Used with Redarc In-Vehicle BCDC Battery Charger
    Since the estimated length of the wire run you'll have with the part # 331-BCDC1240D is between 18 and 20 feet you'd want to use 4 gauge wire. If the run was less than 16 feet you could use 6 gauge. The two relay kits you mentioned actually provide different purposes. The part # 331-SBI12KIT is for allowing the charger to charge two batteries in the best way possible whereas the # 331-RK1260 is for connecting to a vehicle that has a smart alternator. These come with all needed circuit...
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  • Can Redarc In-Vehicle BCDC Battery Charger be Used to Jump Start Battery
    In addition to the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1225D you need to use a Redarc Smart Start Battery Isolator. I recommend using the Battery Isolator with Wiring Kit # 331-SBI12KIT if you don't already have the fuse kit, or part # 331-SBI12D if you do already have the fuse kit. With the isolator installed you can then connect a push-button into your system to help jump your start battery.
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    Thank you so much for all of the info! The Battery Isolation Solenoid # PK5231201 does serve it's purpose but I do understand the need for something that is able to do a bit more. The best solution that we have to offer is the Redarc Smart Start Battery Isolator with Wiring Kit # 331-SBI12KIT because it allows you to install the isolator in-between the start and auxiliary batteries instead of having to install it between the alternator and batteries (it is recommended to have it near...
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  • How To Charge On-Board Auxiliary Battery from Start Battery on Vehicle
    If you're looking to change an on-board auxiliary battery from the main battery then I recommend using the Redarc Smart Start Battery Isolator with Wiring Kit part # 331-SBI12KIT. This kit has everything you need to hook up the auxiliary to the start battery and it has built-in features to prevent the auxiliary battery from draining the start battery.
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    We do have the Redarc Smart Start Battery Isolator with Wiring Kit # 331-SBI12KIT which will allow you to add a 2nd deep cycle Battery # BRW34FR to your trailer. This will allow you to connect to your existing battery but isolate it from being drained by the hydraulic ramp. You do have the option of adding a Momentary Switch # 37213845 if you want to be able to pull power from your 2nd battery in the event the ramp battery dies. You would need to place the switch near the controls for the...
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  • How to Connect Redarc Smart Start Battery Isolator with Wiring Kit on a 1992 Class B Motorhome
    The only connections from the Redarc Smart Start Battery Isolator with Wiring Kit # 331-SBI12KIT to your start and auxiliary batteries are the positive posts. This kit comes with enough wiring to reach from one to the next so you won't be connecting the exciter wire from your alternator to this system. You'll want to connect this isolator per the diagram I'm linking a photo of.
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  • Does Redarc Smart Start Battery Isolator Need to Install on Trailer and Tow Vehicle
    You would only need to have the Redarc Smart Start Battery Isolator # 331-SBI12KIT installed on your tow vehicle for it to charge properly so it sounds like the wiring from the fridge to where it connects to your trailer connector is the problem and most likely too light of a gauge wire. I would recommend going with a really heavy gauge wire for this like 8 gauge to ensure it can carry the current required.
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    From what you described it does not sound like your problem is caused by the Progressive Dynamics Converter/Charger, so you will not have to replace it. I do have an option to better charge the 6V batteries on your RV with your 2014 Toyota Tundra, but I suggest checking the wiring on your 6V to make sure they are wired correctly. The batteries should be wired in series for your situation. I have attached a picture to illustrate how the wiring should be. Your Tundra is probably not charging...
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  • How To Jump Start Battery Using Redarc In-Vehicle BCDC Battery Charger
    The Redarc In-Vehicle BCDC Battery Charger part # 331-BCDC1240D is a great option for charging a trailer battery. It sounds like you are concerned with the status of the starter battery and if that is case there is no need to worry as there are built-in safeguards to prevent puling power from the start battery when it gets below a certain voltage. If for some reason the start battery does die, you can use the auxiliary battery to jump start this with the Redarc Smart Start Battery Isolator...
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    Yes, leaving the trailer attached to the vehicle via the trailer connector can drain the vehicle battery as the vehicle battery is providing power to the trailer battery via the battery charge line circuit run through the trailer connector. That said, if you install a smart device on this circuit it can sense when the vehicle battery gets too low and it will shut the circuit off, it can even take power from the trailer battery if the vehicle battery is too low to start the vehicle. The...
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  • How To Fix Trailer Battery Draining Vehicle Battery
    It sounds like you have an issue with the trailer battery draining the vehicle battery and in which case you would just need a smart device that better manages what power you have. For example, you should only be charging the trailer battery while you are getting a charge from the alternator to the vehicle battery. In order to ensure this happens you can use the Redarc Smart Start Battery Isolator with Wiring Kit part # 331-SBI12KIT which will also shut power off to the trailer battery...
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  • Can You Install an Auxiliary Battery in a Truck Bed and Use for Power
    The only issue you'll run into installing an auxiliary battery in the truck bed would be keeping it charged. In order to do this you'll need to pull said charge from the vehicle's start battery unless you want to remove the battery and plug it in somewhere with a wall outlet each time. There also needs to be some sort of smart device in-between so you can be sure it doesn't pull too much juice from the vehicle's main battery. For this, I recommend the Redarc Smart Start Battery Isolator...
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  • How to Wire Two 6 Volt Batteries to a 12 Volt Battery
    I attached a picture that shows how to run batteries in both series and parallel. You will need to wire up the two 6 volt batteries like the picture on the left so that they would be in series and at 12 volts. To connect a 12 volt battery to that circuit you would need to run the positive post of the 12 volt battery to the positive side of the battery run on the in series batteries. Not the one that is connecting the two batteries, the one that would be the output of the two in-series...
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  • Recommended Override Switch To Jump Dead Battery With Redarc Smart Battery Isolator 331-SBI12KIT
    For the override function of the Redarc Smart Start Battery Isolator with Wiring Kit - 12 Volt - 100 Amp # 331-SBI12KIT that allows you to jump start a dead starting battery with the auxiliary battery you will need a standard momentary switch like the # BDW20284. You will wire the switch in one of the three ways shown in the included diagram. I also included a video review of the products mentioned for you to take a look at.
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  • How to Determine if 2016 Jeep Cherokee Has Smart Alternator
    From what I could find it doesn't look like a 2016 Jeep Cherokee has a smart alternator, but you can (and should) still do a little test on your own to determine if the Redarc Smart Start Battery Isolator with Wiring Kit # 331-SBI12KIT is necessary for the installation of the Redarc In-Vehicle BCDC Battery Charger # 331-BCDC1225D. To determine if your Cherokee has a smart alternator you just need to measure the amount of volts it has, using a multimeter # PT89ZR, after leaving the engine...
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Do you have a question about this Battery Charger?


Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jeff D
Installed by:
Jeff D
Employee Jameson C
Expert Research:
Jameson C
Employee Chris R
Video Edited:
Chris R
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Brian T
Written by:
Brian T

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