True® Large Lithium Dual Battery Kit

(8 customer reviews)


The lithium dual battery kit is for boats, cars, 4WD, trucks, caravans, RVs, or general automotive and marine applications. True® 140 Amp Voltage Sensitive Relay priority charging for starting battery alternator outputs up to 150 amps.


The Large Lithium dual battery kit is for boats, cars, 4WDs, trucks, Vans, RVs, or general automotive & marine applications. The True® Lithium 140 Amp Voltage Sensitive Relay offers Priority charging for your Primary/starting battery, can be used with Alternators with outputs up to 150 amps. 

The True Lithium dual battery kit offers

  • automatic battery management
  • easy to install lithium dual battery system with a wiring diagram
  • Waterproof cable 
  • shockproof, casing, and
  • heat resistant cables for safe and efficient use of the auxiliary battery system.

Everything needed to connect a second lithium battery located as far as 20 feet from the primary battery.


  •  1 True® Smart Lithium Battery Isolator with mounting screws
  •  20 feet #6 high flex red cable with tinned copper cable lugs
  •  3 feet #6 high flex black cable with tinned copper cable lugs
  •  2 positive brass alloy battery terminal ends
  •  2 negative brass alloy battery terminal end
  •  3 loose crimp on tinned copper cable lugs
  •  4 sections of adhesive lined shrink tube
  •  5 zip ties
  •  1 installation instructions booklet

This True® lithium dual battery kit comes packed in a heavyweight zip bag for installer/consumer use.


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8 reviews for True® Large Lithium Dual Battery Kit

  1. Joyce Colbs

    The lithium dual battery isolator has operated according to plan. The wet cell starting battery is also properly charged, and the lithium batteries can be charged without overtaxing the alternator. Also, it stops the wet cell starting battery from being overcharged when using the generator or shore power.

    When upgrading to multiple lithium batteries on a motorhome, the Large Lithium Dual Battery Kit is required. If not, you risk overworking your alternator or charging your new lithium batteries too slowly.

  2. Pualina Trotter

    We mounted this on our F450 to aid in fifth-wheel lithium battery charging. So far, it has been performing excellently. The only concern is the F450’s lack of instructions.

  3. Marcus

    My 2nd purchase of the Lithium dual batter yisolator, and by far the greatest one in terms of functionality! An essential item if you have two batteries. Without a doubt, I would purchase again!

  4. Mark

    The opposite battery jump option has saved my bacon several times. It works as described. Use with my Lifepo4 and BMS. Charges my batteries while I drive. Worth every cent!

  5. Jonathan Gray

    It seems to operate well and is simple to install. Have been on the truck for several months. Seems to be functioning well. There were no difficulties with drainage.

  6. John Harryson

    This Lithium dual battery isolator has fulfilled its promise to the letter. Maintaining my auxiliary batteries charged and ready for both remote work locations and camping has not presented any problems for me.

  7. Steve Brown

    This is a good feature since it isolates the two lithium batteries and connects them automatically. The button’s operation is a touch complex, but the rest of the product is fantastic.

  8. Kelly Stirling

    This is an excellent Lithium dual battery isolator. I used it briefly in my pickup before switching to Lifepo4 batteries. My lead acid crank battery had a dead cell, which emptied my auxiliary battery within a day or two. I can say the emergency button works; follow the directions…..I wish there was a model that isolates at greater voltages for lithium-ion batteries.

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