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
Three Phase 380V Tuya WiFi Smart Bi-Directional Energy Power kWh Meter Over Under Voltage Protector Relay Switch Current Limit
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
63A Tuya WiFi Smart Circuit Breaker Switch Energy Meter Metering Timer Relay Device With Voltage Current and Leakage Protection
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
Tuya ZigBee WiFi Smart Circuit Breaker 1P+N 63A MCB Timer Relay Switch Energy Meter kWh Voltage Current Protector Remote Control
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
Tuya WiFi Smart Bidirectional Energy Meter Power kWh Meter Earth Leakage Over Under Voltage Protector Timer Relay Switch Breaker
Aliexpress UK
A small compact module to generate 2 x 12v ignition live outputs when the 12v engine is running on a vehicle.
eBay
63A TUYA WiFi Smart Earth Leakage Over Under Voltage Protector Relay Device Switch Breaker Energy Power kWh Meter Smart Life
Aliexpress UK
3mtrs 110amp 16mm2 Red Power Cable. 1mtr 110amp 16mm2 black Earth Cable. 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
Voltage Sensitive Split Charge 12V 140A Relay VSR for Camper Car Smart Battery Isolator Car Accessories Charge 2 Battery Bank
Aliexpress UK
Dual Battery Isolators also feature surge protection and a L.E.D indicator designed to alert the user when the unit is engaged. - Suitable for most 12V charging systems- Surge protection. When your engine is switched off, the relay will isolate your leisure battery(s) from your main starter battery.
eBay
220V 230VAC 63A Adjustable Over Under Voltage Surge Protector Relay Over Current Limit Watt kWH Energy Meter Power Consumption
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
Tuya 2P 100A WiFi Smart Bi-Directional Energy Power kWh Meter Leakage Over Under Voltage Protector Relay Switch Current Limit
Aliexpress UK