Dual Battery Isolator Kit, 12V 300A VSR, LCD Voltmeter

Dual battery isolator kit keeps your starter battery protected while reliably charging an auxiliary battery for UTV, ATV, RV, truck, boat, and off-grid setups. The 12V 300A voltage sensitive relay supports lithium and lead-acid batteries, with manual and automatic modes for flexible power control. A dual LCD voltmeter shows both battery voltages in real time, helping you spot issues early and manage loads with confidence in rough outdoor conditions.

• Delivers 300A high-current split charging for dual-battery systems on 12V vehicles and equipment.


• Switches between Auto and Manual modes to combine batteries when needed for emergency starting support.


• Displays dual battery voltage on a bright LCD (4.5–20V) for fast diagnostics and status checks.


• Reduces relay chatter with an adjustable 3–60s delay to help protect isolator and battery lifespan.


• Includes heavy-duty 2 AWG copper cables, lugs, heat shrink, and hardware for a clean install.

Built for demanding installs, this smart isolator adds overvoltage/undervoltage protection plus a compact, shock- and dust-resistant housing for consistent power management on trails, worksites, and remote camps. Use it to keep critical electronics running on an auxiliary battery without risking a no-start situation, then combine batteries when conditions call for it. Everything needed for wiring is in the box, making it easier to upgrade your dual-battery system with fewer extra purchases. Grab yours today and set up dependable power where you need it.

• System rating: DC 12V, 300A


• Voltage display range: 4.5V–20V (dual display)


• Delay time: adjustable 3–60 seconds


• Main materials: PA6 plastic isolator housing, copper wire


• Isolator size: 3.5 x 3.5 x 3.1 in (90 x 90 x 80 mm)


• Net weight (with accessories): 7.3 lb (3.3 kg)


• Cable: 20 ft (6 m) 2 AWG red cable; 2 ft (0.6 m) 2 AWG black ground cable


• In the box: isolator w/ mounting screws, 3 copper connectors, 2 heat shrink tubes, 4 cable lugs, 6 zip ties