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
18650 Power Bank Battery Charger Case 5V 1A Portable USB Power Bank Kit Storage DIY Box For Phone MP3 Electronic Charging
Aliexpress UK
7m kit The kit includes everything you need for setup dual battery charging system 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
Charger Protector Cable Organiser For iPhone 15 14 11 13 18W 20W Charging Protection Cover Data Cable Management Cord Winder Kit
Aliexpress UK
6way Fuse Box with 12 fuse blades & Label Stickers. 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
60W Type-C To USB C To Micro To Lighting Fast Charging Cable Adapter Kit for IPhone 14 13 15 Pro OTG Charger Multi Storage Box
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
100pcs/ kit 10 Models Micro USB MINI usb female Android mobile phone charging accessories Connector Socket Jack MP3/4/5
Aliexpress UK
6mm sq Red cable Power Feed (5m long). The kit has everything that you need to install a split charging system in your vehicle including a relay that prevents your main battery from draining while the engine is stopped.
eBay
For Xiaomi 120W Fast Charging Charger Plug Data Cord Kit For Mi Redmi Note 14 13 12T POCO X4 Quick Charge Adapter US/EU/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
Rechargeable Battery DIY Kit 18650 Power Bank Charge Storage Box Digital Display 4 Output Interface For Charging Mobile Phones
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
Small Home 6000w Solar System 6000W Inverter 30A Controller Solar Panel phone Car Charging Camping Home Solar Power System Kit
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
1-10PCS 22.5W Power Bank 5-port Bidirectional Fast Charging Mobile Power Module Circuit Board DIY Motherboard Kit QC4+PD3.0
Aliexpress UK