Sterling 140A Voltage Sensitive Relay - 12V VSR, Campervan & Marine

Sterling 140A Voltage Sensitive Relay (VSR) — a genuine Sterling Automotive Electrics 12V voltage sensitive relay, designed to safely charge two separate battery banks from a single charging source, such as a vehicle alternator, without risking a flat starter battery.

By monitoring battery voltage, the VSR automatically connects the secondary (leisure) battery only when the primary battery is fully charged. When voltage drops, the relay disconnects, ensuring your starter battery is always protected.

With dual-sensing technology, the relay can detect charging from either battery. This allows charging from external sources such as solar panels or mains chargers, making it ideal for campervans, motorhomes, boats, and 4x4s.

The solid-state, encapsulated design offers zero voltage drop, no moving parts, and excellent reliability in demanding environments.

Brand
Sterling Automotive Electrics

Voltage
12V DC

Current rating
140A continuous

Sense type
Dual sensing (both batteries)

Cut-in voltage
13.3V DC

Cut-out voltage
12.8V DC

Indicator
LED on when engaged

Stud size
M6

Ground connection
Negative (0.5m/18 AWG wire)

Construction
Encapsulated solid-state

Ignition protection
UL1107 compliant

Approvals
CE

Weight
0.2kg

Dimensions
68mm x 68mm x 49mm

Ideal for
Campervan and motorhome conversions, split charging systems, marine and boat battery setups, 4x4 and off-grid vehicle builds, alternator, solar or mains charging systems

Must be correctly earthed for proper operation. For 12V systems only.

Also known as a VSR, split charge relay, or voltage sensing relay.