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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2P AC 230V Tuya WiFi Smart Circuit Earth Leakage Over Under Voltage Protector Relay Device Switch Breaker Energy Power kWh Meter
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
SmartLife TUYA WIFI 2P/63A Circuit breaker Earth Leakage Over Under Voltage Protection Protector Relay Switch Energy kWh Meter
Aliexpress UK
Built-in LED indication (lights up when VSR starts). 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
1-63A 1P+N Tuya WiFi Smart Circuit Breaker Switch Kwh Metering Timer Relay MCB Voltage Current Protect Alexa Google Home Alice
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
2P 230V Tuya WiFi Smart Circuit Earth Leakage Over Under Voltage Protector Relay Device Switch Breaker Energy Power kWh Meter
Aliexpress UK
(via a fuse!). and link to the leisure battery. Fully epoxy sealed unit for years of trouble free service. Bi-Directional, zero loss Split Charging. Only 3 Connections to make. Sealed for marine/under hood installation.
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RMshebei 100A tuya smart life WiFi MCB Prepaid Meter smart circuit breaker Voltage relay 220v Mobile Phone Remote Control pv
Aliexpress UK
Consumption OFF - 12V = 1.5mA / 24V = 1.5mA. The BS100 is ideal for use in multi battery systems on boats, cars, caravans and campervans. Battery Connection - M6. Max Current - 100A. ALM Electrical Solutions is the UK's premier supplier of auto electrical parts and products.
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TUYA 1-63A 1P WIFI Smart Switch Energy Meter Circuit Breaker Voltage Current Protection Relay Control
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.
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WIFI Circuit Breaker TUYA Smart Switch Overload Over Voltage Current Proteciton Temperature Control Relay Energy Meter 1P+N
Aliexpress UK
【Fit All types of Battery】 -- Fit for Lithium Battery, Lead-acid Battery, AGM Battery etc. 【Delay Setting Function】 —— The new delay function avoids frequent switching on and off of the isolator due to unstable current, which prolongs the isolator and battery life.
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RMshebei Tuya smart switch circuit breaker rail Voltage relay 220v earth leakage smart life wifi power meter programmable timer
Aliexpress UK