What is split charging?
Split charging is the term used to describe the simultaneous charging of the vehicle starter battery and the leisure battery (or batteries) from a common charging source. Modern split charge systems typically have a device that connects the starter and leisure batteries only when a charging source is operating, and electrically isolates them otherwise, ensuring that the use of one battery does not draw current from the other. It is important to ensure that the starter battery is isolated so the engine can always be started, but you also don't want the leisure battery to be accidentally drawn upon when starting the engine because dedicated leisure batteries are not designed for high current output over short periods of time and can be damaged.
12V, 140A rated voltage-sensitive relay allows charge to flow into one battery (or bank of batteries) only when a charging voltage is detected at the other battery (dual sensing operation).
- Dual sensing operation - charges from starter battery to leisure battery when the alternator is running and charges from leisure battery to starter battery when mains charger is connected.
- The relay connects when sensed voltage reaches 13.7V or higher
- Relay disconnects when sensed voltage drops to 12.8V or lower
- Maintains battery isolation when not charging, so the starter cannot be drained by leisure use and vice-versa.
- Ignition protection to UL1107
- Fully automatic operation
- E Mark approval
- Virtually zero voltage drop
- Protects sensitive electronic equipment from harmful engine start-up spikes
- Well-proven design with 1000s of units operating in the field
- Terminal connections marked on inside of the unit for easy installation
Note: The benefit of this type of relay is that it does not require a connection to the alternator or any modifications to the existing vehicle electrical system. Simply connect the +ve terminals on each of your batteries to the terminals on the relay and the black relay wire to a common -ve point.
An LED indicates when the relay is ON (contacts closed). Fixing holes in the body allows the unit to be mounted to a bulkhead and body cut-outs offer various cable routing options.
Fully encapsulated electronics make this unit splashproof and particularly suitable for harsh environments (marine use, vehicle engine bays etc.)
IMPORTANT NOTE: These relays are not suitable for vehicles with 'smart' or 'intelligent' alternators. As a guide this applies to vehicles having engines that comply with Euro5 emissions standards and onward, often also incorporating regenerative braking (if in doubt please consult your vehicle manufacturer to confirm). If your vehicle has a smart alternator then you will need to use a battery-to-battery Energy Combiner instead of a VSR.
- Sensing mode: Dual (2-way split charging, starter to leisure and vice-versa)
- Voltage rating (nominal): 12V DC
- Current rating: 140A
- 'Cut-in' voltage: 13.7V
- 'Cut-out' voltage: 12.8V
- Terminal size: 2 x M6 studs and nuts
- Other connections: Ground wire to connect to common -ve
- Ground wire: 1mm² 50cm long approx.
- Fixing hole dia: 5mm
- Overall dimensions: 67 (W) x 67 (H) x 50 (D) mm
Part Number: 4015
Easy to install
This type of split charge device is the most popular on the market for campervan conversions. They are relatively simple to fit and reliable.