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
Solar Charge Controller 60A 12V/24V Voltage Regulator Solar Panel Photovoltaic Home with PWM Solar Charger LCD Display Dual USB
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
1000W Solar Panel 12V Solar Cell With 60A 100A Controller Solar Charge for Phone RV Car MP3 PAD Charger Outdoor Battery Supply
Aliexpress UK
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
Type-C 15W 3A 18650 Lithium Battery Charger Module DC-DC Step Up Booster Fast Charge UPS Power Supply / Converter 5V 9V 12V
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
12V/24V 30A/40A/50A/60A High Definition LCD Large Digital Display Bluetooth WIFI Solar Charge Controller MPPT Controller Solar
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
POWLSOJX MPPT 100A 80A 60A Solar Charge Controller 12V 24V 36V 48V Solar Panel Lead Acid/Lithium Battery Regulator Dual USB
Aliexpress UK
Allows split charging of second battery bank without discharging the primary/start battery, relay makes at 13.7 volts and breaks at 12.8 volt. 12 volt 160 amp. We operate a dispatch policy to ensure your parcel will be processed within 24 hours.
eBay
POWLSOJX 12V/24V PWM Solar Charge Controller 10A/20A/30A with Color LCD Screen, Adjustable Voltage, Multi-Battery Support
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
New Solar Charge Controller PWM Controller With LCD Display 10A 20A 30A 12V 24V Dual USB 5V Output Solar Panel Charger Regulator
Aliexpress UK
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
Solar Charge Controller 12V/24V PWM 10A 20A 30A with Adjustable LCD Display Timer Setting
Aliexpress UK