Having solar power in your van means that you can live largely or completely off the grid with LED lights, fridge, phones and computers without having to worrying about electric bills or power outages. However, sometimes solar power alone may not be enough, especially if your budget does not allow you to throw down a huge multi-panel system.
Situations like cloudy weather, wildfire smoke, and camping in shady forests limit the amount of sunlight and thus the amount of power you can get from the panel. Even with larger four-panel solar system, it is possible to run into problems with battery drain after 3-5 days of poor sunlight conditions.
That is why we highly recommend installing a voltage sensitive relay in your camping build. A voltage sensitive relay is a cost-effective way to supplement your solar panels and make sure your batteries stay topped off no matter the weather. And if you’re on a tight budget, you can even skip the solar and still have basic electricity with nothing but a good voltage sensitive relay and a deep cycle battery.
Every vehicle has an alternator, which is a device that converts the mechanical energy from your van’s engine into electricity and uses that electricity to charge your starting battery. A voltage sensitive relay is a device that allows you to charge a second (auxiliary) battery from your van’s alternator. You can easily use your alternator to charge your auxiliary battery simply by connecting the positive terminals of both batteries. But connecting your batteries this way means that when the engine is turned off, your electrical loads will also drain the starting battery – not good if you want to start your van in the morning!
That is where a voltage sensitive relay comes in. A voltage sensitive relay isolates your batteries so that your alternator will only charge your auxiliary battery when the engine is running, and your electrical loads won’t drain your starting battery. Life on the road means a fair amount of driving, and having the ability to charge your batteries from your engine is a great way to increase your power efficiency and make sure you have electricity when you need it.