--- product_id: 16669226 title: "Dual Battery Isolator Kit 12V - 140 Amp Voltage Sensitive Relay (VSR) for Dual Battery Setup - Automatic Disconnect Switch for Car, Truck, RV, UTV, ATV, Marine" brand: "keyline chargers" price: "€ 152.27" currency: EUR in_stock: true reviews_count: 12 category: "Key Line Chargers" url: https://www.desertcart.hr/products/16669226-dual-battery-isolator-kit-12v-140-amp-voltage-sensitive-relay store_origin: HR region: Croatia --- # 140 Amp max current 12V smart voltage sensing IP65 water & dust resistant Dual Battery Isolator Kit 12V - 140 Amp Voltage Sensitive Relay (VSR) for Dual Battery Setup - Automatic Disconnect Switch for Car, Truck, RV, UTV, ATV, Marine **Brand:** keyline chargers **Price:** € 152.27 **Availability:** βœ… In Stock ## Summary > πŸ”Œ Power up your dual battery setup like a pro β€” never get stranded again! ## Quick Answers - **What is this?** Dual Battery Isolator Kit 12V - 140 Amp Voltage Sensitive Relay (VSR) for Dual Battery Setup - Automatic Disconnect Switch for Car, Truck, RV, UTV, ATV, Marine by keyline chargers - **How much does it cost?** € 152.27 with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/16669226-dual-battery-isolator-kit-12v-140-amp-voltage-sensitive-relay) ## Best For - keyline chargers enthusiasts ## Why This Product - Trusted keyline chargers brand quality - Free international shipping included - Worldwide delivery with tracking - 15-day hassle-free returns ## Key Features - β€’ **Seamless Power Flow:** Eliminates voltage drops for max battery efficiency - β€’ **Rugged & Weatherproof:** IP65-rated solid-state design built for off-road, marine, and daily use - β€’ **Compact & Easy Install:** Small 2.6” cube fits under hood or battery relocation kits with simple DIY setup - β€’ **Peace of Mind Warranty:** 12-month industry-leading warranty + 30-day money-back guarantee - β€’ **Smart Voltage Activation:** Automatically connects at 13.3V, disconnects at 12.8V to protect your starter battery ## Overview The KeyLine Dual Battery Isolator Kit is a 12V, 140 Amp smart voltage sensitive relay designed to optimize dual battery systems in vehicles, RVs, and marine applications. It automatically manages power flow between batteries without voltage loss, features a compact IP65-rated rugged design for extreme conditions, and includes easy installation hardware. Backed by a 12-month warranty and 30-day money-back guarantee, it ensures reliable, maintenance-free battery isolation and charging. ## Description Buy Dual Battery Isolator Kit 12V - 140 Amp Voltage Sensitive Relay (VSR) for Dual Battery Setup - Automatic Disconnect Switch for Car, Truck, RV, UTV, ATV, Marine: Battery Relocation Kits - desertcart.com βœ“ FREE DELIVERY possible on eligible purchases Review: The best solution for battery isolation - I was looking for a good quality relay to be used in my Chevy truck to isolate an auxiliary battery. My OEM relay failed, but it was 30 years old. The auxiliary battery is used as one of two batteries for my pickup camper - one is in the engine compartment and the other in the camper. I tried three different isolation relays, two of which looked pretty good. The Stinger SGP32 was the best, since it drew the least amount of current when activated. But then further searching brought me to this relay, which works with a clever design using voltage rather than just an ignition circuit. I ordered one of these and the Jaycorp Smart Battery Isolator, which also looked good. When I received them from desertcart I found them to be almost identical in design, and upon bench testing they both worked perfectly. I ended up keeping the Keyline product and returning the Jaycorp relay, but only because I liked the small red LED a bit better than the bright blue LED on the Jaycorp relay. Either relay looks to be a great solution for battery isolation. If this Keyline product proves reliable, I'll be a very happy camper! Update 8/3/21: This isolator has worked perfectly since I installed it. A 5 star product! Review: Does the job and saves batteries - This was purchased to isolate an RV auxiliary battery used for starting the generator from the start battery bank for my engine. The original design had these two batteries banks connected together for charging purposes, but not isolated. Since the auxiliary battery was a smaller capacity battery it could drain the chassis battery during long storage periods leaving me with a dead chassis battery. Now with the battery isolator the two batteries are disconnected from one another unless the engine alternator, or other charging source, is supplying a charging voltage to the chassis battery. The battery isolator then applies the full charging voltage to the auxiliary battery, when needed, allowing it to recharge . Diode isolators have been used for this purpose and work ok, but they have a voltage drop across the diode which limits the charging that can occur. Diode isolators are solid state devices and can be susceptible to voltage spikes. This device is a much better solution. its rugged, delivers a full charging voltage to the load battery, and isolates the charging source battery when there is no charging voltage being applied. No dead battery after 6 months of winter storage. ## Features - Advanced Dual Battery Isolator 12V Kit – Designed for superior performance, this dual battery kit ensures efficient power distribution between two batteries without voltage drops. Unlike traditional battery isolator diodes, this automatic disconnect switch eliminates power loss while maintaining a seamless connection between your primary and auxiliary power sources. Compact at 2.6” x 2.6” x 2”, it’s perfect for under-hood installations or as part of a battery relocation kit. - Smart Voltage Sensitive Relay (VSR) for Optimal Charging – Featuring a 12V dual battery wiring kit, this system automatically activates at 13.3V and disengages at 12.8V, ensuring your starting battery remains fully charged. Whether you're installing a marine dual battery kit for your boat, a dual battery kit for truck applications, or need a battery isolator 12V kit for off-grid power, this setup prevents battery drain and guarantees reliable performance. - Built for Extreme Conditions & Rugged Durability – Engineered for off-road adventures, marine use, and daily driving, this dual battery isolator kit is IP65-rated for water, dust, and vibration resistance. Its solid-state design ensures durability, making it an excellent choice for automotive, RV, UTV, and marine battery isolator needs. Whether battling tough trails or navigating open waters, count on this dual battery wiring kit to provide uninterrupted power. - EASY-TO-USE: The 140 Amp Dual Battery Smart Isolator comes with mounting plate and hardware. Does not include installation wires. Easy-to-follow directions for the most novice DIYer. What could be easier? **If you need installation wiring, see Dual Battery Kit or ATV/UTV Kit. - Trusted Performance with Warranty & Money-Back Guarantee – Every dual battery kit by KeyLine Chargers is backed by a 12-month industry-leading warranty. If you’re not 100% satisfied with your purchase, take advantage of our 30-day money-back guaranteeβ€”no questions asked! Drive with confidence knowing you have a premium battery isolator 12V kit keeping your power system running at full capacity. ## Technical Specifications | Specification | Value | |---------------|-------| | ASIN | B00WTAFR84 | | Best Sellers Rank | #31,225 in Automotive ( See Top 100 in Automotive ) #4 in Automotive Replacement Battery Relocation Kits | | Date First Available | April 28, 2015 | | Is Discontinued By Manufacturer | No | | Item Weight | 9.6 ounces | | Item model number | ISO-Variation | | Manufacturer | KeyLine Chargers | | Product Dimensions | 1.97 x 1.97 x 1.97 inches | ## Images ![Dual Battery Isolator Kit 12V - 140 Amp Voltage Sensitive Relay (VSR) for Dual Battery Setup - Automatic Disconnect Switch for Car, Truck, RV, UTV, ATV, Marine - Image 1](https://m.media-amazon.com/images/I/718YwOW-isL.jpg) ## Available Options This product comes in different **Size** options. ## Questions & Answers **Q: What gauge is the supplied wires?** A: The kit comes with 7 AWG wire, but wanted to comment on the customer who stated that it is not enough for a 20 foot run. At 140 amps, you would need 1/0 AWG wire, but with 95% of the applications out there, the most current that is drawn is around 30-50 amps and that is why we designed the kit with 7 AWG for the 20 foot run. I hope that helps clarify. **Q: Will the alternator charge battery 2 with this while car is running** A: Yes it will. That is precisely one of the features it is designed to do. Thanks **Q: I have a 2020 wrangler with a 240 amp alternator. is this rated to work with my alternator? i will be adding a second battery for low-draw accessories** A: Hello, a 240 amp alternator is definitely a big alternator, however, it is rare that an application would draw more than 40-60 amps at any one time. It is not so much the alternator size that would cause a problem for our isolator it is the draw from the accessories. I would recommend adding up the amperage draw from your accessories when they would all be on and determine the draw, if it is under 140amps then it will work well. If you decide to go ahead and use our Keyline Battery Isolator then you may want to install a large 140 amp fuse or breaker to ensure your alternator won't fry the isolator, but again that would be a rare accessory draw application like an induction cooktop or something similar that would draw over 100amps. Remember that the alternator is only going to push enough amps to power the draw of the accessories and to charge the battery (which also has a low amperage draw). Hope that helps. Thanks for the question. **Q: can this be use to charge a lithium batteries on the second battery?** A: Short answer: it depends. Longer answer: it depends on the Li bank capacity, battery charging specs, alternator specs, resistance of the entire circuit, etc. In my case I replaced 220Ah of flooded lead-acid with 100Ah of LiFePO4 and demand on the alternator actually /decreased/ a bit. If the isolator is already installed you could test it briefly to see what voltage/current from the alternator is like. If you do not already have the isolator a DC-DC sized to your alternator's rating would be a safer bet. ## Customer Reviews ### ⭐⭐⭐⭐⭐ The best solution for battery isolation *by R***L on September 4, 2019* I was looking for a good quality relay to be used in my Chevy truck to isolate an auxiliary battery. My OEM relay failed, but it was 30 years old. The auxiliary battery is used as one of two batteries for my pickup camper - one is in the engine compartment and the other in the camper. I tried three different isolation relays, two of which looked pretty good. The Stinger SGP32 was the best, since it drew the least amount of current when activated. But then further searching brought me to this relay, which works with a clever design using voltage rather than just an ignition circuit. I ordered one of these and the Jaycorp Smart Battery Isolator, which also looked good. When I received them from amazon I found them to be almost identical in design, and upon bench testing they both worked perfectly. I ended up keeping the Keyline product and returning the Jaycorp relay, but only because I liked the small red LED a bit better than the bright blue LED on the Jaycorp relay. Either relay looks to be a great solution for battery isolation. If this Keyline product proves reliable, I'll be a very happy camper! Update 8/3/21: This isolator has worked perfectly since I installed it. A 5 star product! ### ⭐⭐⭐⭐⭐ Does the job and saves batteries *by F***O on June 12, 2018* This was purchased to isolate an RV auxiliary battery used for starting the generator from the start battery bank for my engine. The original design had these two batteries banks connected together for charging purposes, but not isolated. Since the auxiliary battery was a smaller capacity battery it could drain the chassis battery during long storage periods leaving me with a dead chassis battery. Now with the battery isolator the two batteries are disconnected from one another unless the engine alternator, or other charging source, is supplying a charging voltage to the chassis battery. The battery isolator then applies the full charging voltage to the auxiliary battery, when needed, allowing it to recharge . Diode isolators have been used for this purpose and work ok, but they have a voltage drop across the diode which limits the charging that can occur. Diode isolators are solid state devices and can be susceptible to voltage spikes. This device is a much better solution. its rugged, delivers a full charging voltage to the load battery, and isolates the charging source battery when there is no charging voltage being applied. No dead battery after 6 months of winter storage. ### ⭐⭐⭐⭐ I'd give it 5 stars but the ground wire wasn't attached very well and easily broke off *by P***Y on May 23, 2018* I installed this on my UTV and it works perfectly. When I have all my lights going at night and the fan kicks on it closes the isolator so I don't have such a load on the stator. I'd give it 5 stars but the ground wire wasn't attached very well and easily broke off. Easy fix, but still the solder job should of been better. ## Frequently Bought Together - Dual Battery Isolator Kit 12V - 140 Amp Voltage Sensitive Relay (VSR) for Dual Battery Setup - Automatic Disconnect Switch for Car, Truck, RV, UTV, ATV, Marine - TKDMR 10pcs 1/0 AWG-3/8 Battery Lugs,Heavy Duty Wire Lugs,Ring Terminals,Battery Cable Ends,0 Guage terminals,Battery Terminal Connectors with 10pcs 3:1 Heat Shrink Tubing - 10pcs 4 Awg - 3/8" (M10) Sanuke Wire Lugs Ring Terminal Connectors Ends, UL Listed Heavy Duty for Battery Cable Lug Wire Electrical Eyelets with 3:1 Dual Wall Adhesive Heat Shrink --- ## Why Shop on Desertcart? - πŸ›’ **Trusted by 1.3+ Million Shoppers** β€” Serving international shoppers since 2016 - 🌍 **Shop Globally** β€” Access 737+ million products across 21 categories - πŸ’° **No Hidden Fees** β€” All customs, duties, and taxes included in the price - πŸ”„ **15-Day Free Returns** β€” Hassle-free returns (30 days for PRO members) - πŸ”’ **Secure Payments** β€” Trusted payment options with buyer protection - ⭐ **TrustPilot Rated 4.5/5** β€” Based on 8,000+ happy customer reviews **Shop now:** [https://www.desertcart.hr/products/16669226-dual-battery-isolator-kit-12v-140-amp-voltage-sensitive-relay](https://www.desertcart.hr/products/16669226-dual-battery-isolator-kit-12v-140-amp-voltage-sensitive-relay) --- *Product available on Desertcart Croatia* *Store origin: HR* *Last updated: 2026-04-25*