Relays

About this product The voltage-sensitive relay adjusts the start and stop thresholds and works with lithium lead-acid and other battery types. This ensures the auxiliary battery is connected as needed and charging time is used efficiently. The optimized coupling reduces deep discharge and extends the lifespan of the energy storage devices. A single button press activates manual mode, allowing a fully charged auxiliary battery to recharge a discharged starter battery, enabling an immediate engine start. In automatic mode, the VSR connects independently based on the stored threshold values and disconnects again as soon as the voltage drops. A delayed connection prevents frequent switching during voltage spikes. Depending on the model, the delay can be set from 3 to 60 seconds or is a fixed 15 seconds. This reduces contact wear, increases the relay's service life, and ensures consistent charging phases. The bright display shows the voltages of both batteries in real time within the range of 4.5 to 20 V. This allows you to check the wiring and charge status at a glance and detect faults early. Whether underway during shore power connection changes or at the dock, the clear display aids in diagnostics and makes energy management transparent. The robust PA6 housing with shock and dust resistance protects the electronics from vibrations, cold, mud, and splashes. Overvoltage and undervoltage protection stabilize operation even during voltage fluctuations. Compact dimensions facilitate installation in tight spaces, such as under seats behind panels or in technical compartments, without modifications to the factory wiring. Key Differences The VSR004 is especially compact and designed for UTVs, ATVs, jet skis, and snowmobiles. It delivers 80 A at 12 V and features a fixed 15-second delay for quick installation in confined spaces. The VSR003 and VSR003 1 offer 140 A at 12 V with an adjustable 3- to 60-second delay and manual coupling for jump-starting. The VSR003 1 version includes a pre-assembled wiring harness and is heavier. The VSR005 and VSR005 1 are designed for high loads up to 300 A at 12 V, making them the ideal choice for high-performance dual systems. The delay is adjustable, and the VSR005 1 variant is available with a heavier cable. Material: The VSR003 and VSR005 are listed as PA6 housings, while the VSR003 1, VSR004, and VSR005 1 are explicitly listed as PA6 insulators with copper conductors. Size: The VSR004 is very compact at 85 x 43 x 37 mm, while the VSR003 (80 x 70 x 60 mm) and VSR005 (90 x 90 x 80 mm) require more installation space. Material: The VSR004 is very compact at 85 x 43 x 37 mm, while the VSR003 (80 x 70 x 60 mm) and VSR005 (90 x 90 x 80 mm) require more installation space. Specifications Model: VSR003 Rated Voltage and Current: DC 12 V 140 A Delay: Adjustable 3–60 s Display Range: 4.5–20 V Dual Display Modes: Automatic and Manual Material: PA6 Product Dimensions: 3.1' x 2.8' x 2.4' / 80 x 70 x 60 mm Net Weight including Accessories: 0.5 lbs / 0.24 kg Color: Black Model: VSR005 Rated Voltage and Current: DC 12 V 300 A Delay: Adjustable 3–60 s Display Range: 4.5–20 V Dual Display Modes: Automatic and Manual Material: PA6 Product Dimensions: 3.5' x 3.5' x 3.1' / 90 x 90 x 80 mm Net Weight including Accessories: 0.9 lbs / 0.42 kg Color: Black Model: VSR004 Rated Voltage and Current: DC 12 V 80 A Delay: Automatic 15 s Material: PA6 insulator housing + copper wire Product Dimensions: 3.3' x 1.7' x 1.5' / 85 x 43 x 37 mm Net Weight including accessories: 0.9 lbs / 0.43 kg Color: Black Model: VSR003-1 Rated Voltage and Current: DC 12 V 140 A Delay: Adjustable 3–60 s Display Range: 4.5–20 V dual display Modes: Automatic and manual Material: PA6 insulator + copper wire Product Dimensions: 3.1' x 2.8' x 2.4' / 80 x 70 x 60 mm Net Weight Including accessories: 3.5 lbs / 1.6 kg Color: Black Model: VSR005-1 Rated Voltage and Current: DC 12 V 300 A Delay: Adjustable 3–60 s Display Range: 4.5–20 V Dual Display Modes: Automatic and Manual Material: PA6 Insulator + Copper Wire Net Weight Including Accessories: 7.3 lbs / 3.3 kg Color: Black Package Contents All Models: 1 x Dual Battery Isolator Kit, 1 x User Manual