In this situation if your voltage sensitive relay (VSR) is off, your auxiliary battery will not receive any charge (even if you override your VSR to stay on, the voltage will be too low for any useful charge into your auxiliary battery). This is done to reduce the load on the engine, reduce fuel consumption but primarily to reduce vehicle emissions. With variable voltage applications there are situations where your start battery is fully charged and once this is determined by the vehicle’s Engine Control Unit (ECU), can reduce the alternator voltage. The operation of a variable voltage alternator when paired with your dual battery system can have some unforeseen or detrimental effects on the operation of the dual battery system and the auxiliary battery. How does a smart alternator affect my dual battery system? This is the battery sensor, if it’s got one of these, you have a variable voltage alternator. What you are looking for is a module mounted on or close to the battery terminal (usually the battery negative). It’s not easy to tell if it’s a variable voltage alternator by only measuring voltage as sometimes the result may be deceiving or look similar to a standard alternator at time of testing.Ī good way to determine whether your vehicle has a variable voltage alternator is to look at the vehicle start battery. Smart alternators are par for the course in most modern vehicles, but when measuring or monitoring output voltage from a vehicle with a variable voltage alternator you will find the voltage can range between 12.3V-15V. How do I tell if I have a smart alternator? Unfortunately, this renders it unsuitable for charging a secondary battery system to a usable level. The idea behind this is to reduce electrical load and in turn mechanical load on the engine by the alternator. The smart alternator system, also known as variable voltage alternators, allow the vehicle to control the output voltage and current from the alternator based on vehicle operating conditions. A fixed voltage alternator has a high enough voltage to charge a secondary battery in the vehicle to a usable level for leisure or auxiliary use. Smart alternators vs fixed voltage alternatorsįixed voltage alternators are becoming less common on new vehicles as reduced fuel consumption targets and more stringent environmental and emissions standards are adopted by manufacturers. Phoenix Inverter VE.With the constant evolution of technology in today’s modern vehicles and an increasing number of accessories and options available, setting up a dual battery system can feel more daunting than ever.Īnd one of the main stumbling blocks when selecting the type of equipment you need to correctly charge and maintain your auxiliary batteries often depends on the type of alternator found in your vehicle.īut what is the difference between smart alternators and fixed voltage alternators? Is it as technical and scary as you think?.Phoenix Inverter Compact 1200VA – 2000VA.However if in doubt, please feel free to contact our customer service team and they can help guide you through.
To make it easy to select the correct battery for your car, we have a battery registration finder which will show the most suitable fitting batteries. Offering many different battery technologies from sealed and maintenance free, to AGM and EFB for vehicles with start stop, we really do have a battery for every car. With the advancement of vehicles, the brands and models of car batteries have had to make the same progress at Battery Megastore, we stock batteries that are both compatible with classic cars and modern cars that have been integrated with stop-start technology.
We also stock premium car battery brands such as Varta, Bosch, Yuasa and Optima all with free next day delivery and long warranties, mostly 4 and 5 years. We directly import the Hankook brand from South Korea meaning we can offer them at great prices whilst still offering a 4 year warranty. Looking for a cheap car battery, why not take a look at our Hankook car battery range. Here at Battery Megastore we stock a large range of car batteries suiting every budget. If you find yourself in need of a car battery, you have come to the right place.