When your engine is switched off, the relay will isolate your leisure battery(s) from your main starter battery. So it does not drain your main starter battery and you will always be able to start your vehicle.
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3m Ready Made Split Charge Relay Kit 12v 140 AMP VSR 110Amp Lead T4 T5 For Caravan Camper Boats Voltage Sensing Relays
Aliexpress UK
Trailing Arm Bush Removal Install Tool For Ford Mondeo Mk4 S-max Galaxy Volvo 06. Engine Timing Locking Tool Kit For Fiat 500 Ford Ka Lancia Petrol 1.2 8V/1.4 16V. Fit For VAG VW Audi Seat Skoda Timing Tool Locking Kit Engine 1.4 1.6 2.0 TDI CR.
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Waterproof Relay DC 12V 100A Relay SPDT 5 Pin Relay Car Heavy Duty Split Charge Waterproof Transparent Case
Aliexpress UK
Your engine is running. When your engine is switched off, the relay will isolate your leisure battery(s) from your main starter battery. So it does not drain your main starter battery and you will always be able to start your vehicle.
eBay
5MTR SPLIT CHARGE KIT RV 12V 140A AMP VSR READY MADE LEADS VOLTAGE SENSE RELAY UK
Aliexpress UK
When your engine is switched off, the relay will isolate your leisure battery(s) from your main starter battery. So it does not drain your main starter battery and you will always be able to start your vehicle.
eBay
3m Ready Made Split Charge Relay Kit 12v 140 AMP VSR 110Amp Lead T4 T5 For Caravan Camper Boats Voltage Sensing Relays
Aliexpress UK
When your engine is switched off, the relay will isolate your leisure battery(s) from your main starter battery. So it does not drain your main starter battery and you will always be able to start your vehicle.
eBay
3m/5m/7m Split Charge Relay Kits Ready Made Leads 12V 140A Voltage Senstive VSR Camper Van
Aliexpress UK
Amperage: 140A. ANS-H Fuse Box: 2 pieces. Heat Shrink Tubing: 6 pieces + 1 black heat shrink tube. ANS Fuse Blades: 2 x 40A square head, 2 x 50A square head, 2 x 60A square head. Wire #1 Black: 1 piece - 1000mm, SC10-8 connectors on both ends, black heat shrink tubing.
eBay
When your engine is switched off, the relay will isolate your leisure battery(s) from your main starter battery. So it does not drain your main starter battery and you will always be able to start your vehicle.
eBay
Suitable for most 12V charging systems- Surge protection. Dual Battery Isolators also feature surge protection and a L.E.D indicator designed to alert the user when the unit is engaged. When your engine is switched off, the relay will isolate your leisure battery(s) from your main starter battery.
eBay