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
30W Solar Charger System IP65 Car Battery Solar Panel Charging Kit 18V Solar Battery Charger Board For Car RV Boat Motorcycle
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
30W 4-in-1 Magnetic Wireless Charger for iPhone 14-16 Pro Galaxy S22-S24, Fast Dual Charging Station for Phone/Watch/Headset
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
DIY 21700 Battery Power Bank Kit 30000mAh Camping LED Light, PD/QC 22.5W Fast Charging USB-C/Micro Input Aluminum Case
Aliexpress UK
6way Fuse Box with 12 fuse blades & Label Stickers. 2 x MTA Midi Fuse holders. 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
4000W Solar Panel Kit 12V To 110V/220V – 6000W Inverter 12V Battery Charging for House RV Camping & Emergency Power
Aliexpress UK
(1 BB1230 Charging Unit. All of the benefits of advanced charging without any of the drawbacks. 4) Current is NOT taken from the input battery and given to the output battery. Manual mode and regenerative braking mode allows you to override this.
eBay
2Pcs/set Kawaii Data Cable Angel Wing Cable Protector Winder Charging Line USB Cable Protector Cable Organizer
Aliexpress UK
Simply connect the relay between your starter battery and leisure battery and the relay takes care of everything, making sure your starter battery is not drained for when you need to get going again.
eBay
5Gbps Data Transfer Charging Cable USB3.0 to Type-C for PSVR2 Oculus Quest 3 /2 Link Cable VR Headset for PICO 4 Accessories
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
13in1 Mobile Phone Charging Port Dust Plug for IPhone 14 13 Pro Max Cleaner Kit Computer Keyboard Earphones Cleaner Brush Tool
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
4Pcs/set Marvel Charger Smart Cover Cute Cartoon Charger Protection for Samsung 25W Data Cable Charging Decoration Accessories
Aliexpress UK