RECOIL 500A Mobile Audio Battery Isolator & Starter Relay — Waterproof, 700A Surge Capacity

RECOIL 500 Amp Mobile Audio Battery Isolator and High Current Starter Relay separates and protects dual battery systems while delivering up to 500A continuous and 700A surge for reliable starts and heavy audio loads.

Designed for vehicles with dual batteries, aftermarket audio systems, winches, or auxiliary power banks, this compact relay/isolator combination keeps your starter battery reserved while allowing high current flow when needed. The RECOIL BRL500 is engineered to reduce unnecessary drains, avoid the voltage loss typical of diode isolators, and offer corrosion-resistant, waterproof performance for demanding mobile environments.

How does the BRL500 prevent one battery from draining another?

The BRL500 acts as an intelligent high-current mechanical relay that connects batteries only when charging voltage is present or when starter support is needed, and isolates them when the engine is off. This prevents loads on accessories from drawing down the main starting battery.

• Automatically isolates batteries when alternator output is absent
• Allows charging to share when alternator voltage is available
• Stops backflow that would let audio or accessories discharge the starter battery

Will it handle big audio amplifiers and heavy starting loads?

Yes — the BRL500 is specified for 500 amps continuous current and tolerates 700 amps surge, matching the needs of large audio systems, high-draw accessories, or demanding starter assistance. Its heavy-duty contacts and alloy materials are built to carry the instantaneous currents common in vehicle starting and audio peaks.

• 500A continuous capacity for sustained loads or large amplifiers
• 700A surge handling for engine cranking and transient peaks
• Robust terminals for thick cable connections and minimal heating

How does the BRL500 compare to conventional isolators and relays?

Unlike diode-based isolators that create a voltage drop, the BRL500 provides a direct low-resistance connection when engaged, so the second battery receives full charging voltage. Compared with simple solenoids, this unit is engineered for mobile audio and accessory setups with weatherproofing and prolonged durability in mind.

• No significant voltage drop to the auxiliary battery while charging
• Waterproof construction suited for off-road and marine exposure
• Designed specifically for mobile audio and high-current starter applications

What installation and maintenance should I expect?

Installation typically requires mounting the relay near the batteries and running appropriately gauged cables between batteries, alternator, and starter. Periodic checks of cable terminations and the relay housing are recommended for long-term reliability, especially in salt or mud-prone environments.

• Mount in a protected, ventilated area close to battery bank
• Use heavy-gauge battery cable and secure terminals tightly
• Inspect seals and fasteners occasionally for corrosion or looseness

Who is this for: The RECOIL BRL500 is aimed at vehicle owners and installers who run dual-battery setups, high-power mobile audio systems, winches, or other high-current accessories and need dependable isolation without charging voltage loss. It's a good fit for overlanders, marine users, emergency vehicles, and anyone who wants to protect their starting battery while ensuring auxiliary batteries receive full charging current under normal operation.