How to charge a leisure battery from a van battery while driving

If you enjoy spending your free time caravanning or exploring new places in a motorhome, knowing the best way to care for and maintain your vehicle and its equipment is vital. And learning a few tips and tricks along the way, such as how to charge up your leisure battery whilst on the move, can help enhance your experience along the way.

What Is A Leisure Battery?

A leisure battery is a battery which is used to power all of the 12V devices in your motorhome or caravan. It is intended to deliver a low amount of energy over a prolonged period of time, making it the ideal choice for powering the interior lights, a kettle, or even a TV set. This, therefore, makes the leisure battery a useful alternative to connecting to the mains at a campsite.

The leisure battery is different to a standard car or van battery, because it is designed for durability and has the ability to hold its charge for a long time, even when not in use. By contrast, a car battery is designed to provide a short burst of power (when you turn the ignition), and can quickly run flat if not put to use frequently.

There are a number of different types of leisure battery available to buy, including lithium-ion, flooded lead-acid (FLA), absorbed glass-mat (AGM), and gel.

Charging A Leisure Battery

There are essentially two methods for charging a leisure battery from your vehicle’s engine: using a split charge relay, or a battery to battery (B2B) charger device. These methods both work by making use of the vehicle engine’s alternator (which converts AC into DC power).

Using a split charge relay is an expensive way to harness the power of the motorhome’s engine, but can only be effectively carried out when the vehicle is safely parked. When used in motion, drawing on the alternator’s power, the leisure battery will not become fully charged. Using a B2B charger, however, allows you to fully charge your leisure battery whilst on the move. It is the more expensive option as the charger itself costs more than a standard split relay device.

A B2B charger is a smart device, as it sees the alternator continue to charge the battery with a continuous voltage supply. It then controls the voltage so that the leisure battery receives the optimum amount of power for its needs, also known as its “charging profile.” Many B2B chargers are programmable, too, allowing the user to achieve the best possible results.

It’s important to note that if you regularly use the power of your engine’s alternator to recharge a leisure battery, the alternator will likely wear out sooner than through normal driving use. It’s also important to check what kind of leisure battery you have, for example, Lithium-ion batteries must be very carefully managed in order to avoid overcharging.

A Practical Solution

In conclusion, a B2B charger makes the best choice if you plan to charge a leisure battery from a van whilst driving. The latest models of charger offer many features that make this an efficient and easy approach.

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