UCkasayfy 12V 140A Dual Battery Isolator VSR — Lead-Acid Only, IP65 Sealed for Marine & RV

UCkasayfy Dual Battery Isolator is a 12V, 140A voltage-sensitive relay that automatically links or isolates two lead-acid batteries to prioritize starting power and allow safe parallel charging.

Designed for automotive, marine and recreational use, this compact VSR engages at 13.3V and disengages at 12.8V to protect your primary starter battery while letting an auxiliary battery charge when the alternator supplies sufficient voltage. Built with sealed internals and an IP65 rating, it tolerates damp and dusty environments. Note: this unit is not compatible with lithium battery chemistries.

How does the UCkasayfy isolator keep my starter battery ready?

The isolator automatically senses voltage and connects batteries only when charging voltage is high enough, preventing accessory drains from leaving you with a dead starter battery. It also allows reverse charging if the main battery needs a boost from the auxiliary.

• Engages at 13.3V, disconnects at 12.8V to protect starter capacity
• Permits parallel charging from a single alternator when needed
• Reverse-charge capable for emergency top-ups from auxiliary battery

Is this VSR durable enough for marine and off-road use?

Yes — the isolator is built with robust components and a silicone-sealed interior to resist moisture and contaminants. Its IP65 rating means it withstands low-pressure water jets and dust exposure common in outdoor and marine settings.

• Silicone-sealed internals for corrosion resistance
• IP65 rated housing to resist water and dust ingress
• Small footprint for installation in tight engine bays or compartments

What vehicles and setups are compatible with this 140A isolator?

The unit is intended for 12V lead-acid systems across a wide range of vehicles and craft, including ATVs, UTVs, cars, trucks, RVs, trailers and boats. It’s sized to handle typical alternator outputs for these applications, but it must not be used with lithium batteries.

• Works with 12V lead-acid starter and auxiliary battery systems
• Suitable for cars, trucks, campers, boats, UTVs and trailers
• Not compatible with lithium or LiFePO4 battery chemistries

What installation details and safety points should I know before fitting?

Installation is straightforward but requires correct wiring, fusing and secure mounting. Place a fuse within the recommended distance from the second battery and ensure connections are tight and corrosion-free. If unsure, have a qualified technician complete the installation.

• Ensure fused connection to auxiliary battery within 0.98 ft (30 cm) as advised
• Mount on a stable surface, avoid direct engine heat and moving parts
• Use appropriate cable sizes for 140A continuous capability and secure terminals

Who this is for: The UCkasayfy 12V 140A VSR is aimed at drivers and owners who run auxiliary electrical systems — like winches, fridges, lighting or accessories — and want a simple, automatic way to keep a second battery charged while preserving primary starter capacity. It’s ideal for recreational vehicle owners, marine enthusiasts and off-road users who use standard lead-acid batteries and need a rugged, sealed isolator for challenging environments. Do not use this model with lithium batteries; choose a lithium-compatible management solution instead.