Leisure Batteries – What are they?

Introduction

There tends to be a lot of confusion about what a Leisure Battery is, and how it differs from other types of batteries such as Car Batteries. In this guide, we will try to dispel any confusion or myths about what a leisure battery is, how it is used and why it differs from other types of batteries such as starter batteries.

What is a Leisure Battery?

First, let’s define what we mean by the term ‘Leisure Battery‘. A leisure battery is the type of battery found in applications where it would often be described as a Caravan Battery, a Motorhome Battery, a Canal Boat Battery or an Electric Fence Battery. The collective term for this type of multi-purpose battery is a Leisure Battery.

What are the Usage Patterns?

So, let’s start at a high level; what are the usage differences between the two main types of batteries – Starter Batteries and Leisure Batteries?

• A Starter Battery (for example, a car battery) is required to (as the name suggests) push out a short quick burst of energy in order to start an engine. This may be a car engine, a boat engine or any other type of internal combustion engine. Turning over a set of heavy pistons and turning cranks requires a large, short push of energy that a starter battery is able to offer.
• A Leisure Battery differs as it is required to push out a slow, steady flow of power out over a longer period of time. So, for example aboard a caravan you may be powering a refrigerator and lights where you’re drawing a smaller amount of power over a far longer period of time.

So is this all marketing? Aren’t batteries all the same inside that plastic case?

No. Absolutely not. The internal makeup of the two types of battery completely differs as we detail below. Remember that as well as the power output differences, leisure batteries are also designed to be discharged to a far lower state of charge than car batteries.

How do Leisure Batteries compare to Start Batteries internally?

Strap yourself in – this is about to get technical! Inside the plastic battery case that you hold in your hands, a lead acid battery is made up of a series of lead-oxide paste covered plates, with separators and submerged in acid (also referred to as electrolyte). This applies to both cranking (starter) batteries and deep cycle (leisure) batteries.

The plates in leisure batteries have thicker plates, and the lead-oxide paste material is generally more dense. The plates are made from manmade alloys and in leisure batteries may contain more of certain additives such as Antimony. Thicker plates have the benefit of being more corrosion-resistant over the expected long life of charge-discharge cycles.

Conversely, starter batteries have thinner plates, less dense lead-oxide paste with different additives added to the plate alloy.

Different Leisure Battery Technologies

You may have heard various terms banded around for the technology employed in leisure battery construction. Hopefully, we can clear things up here:

• Wet / Flooded Leisure Batteries: Wet batteries (often referred to as flooded) are pretty much what is described above; a plastic container filled with electrolyte, with the lead-oxide covered alloy plates inserted with separator material between them.
• Maintenance Free Leisure Batteries: traditionally, 12V wet batteries have six removable caps on the top, (one per 2.1 Volt cell) which can be used to top up the six cells with de-ionised water which can be lost due to gassing when being charged. Maintenance Free (MF) batteries drop these six caps and a different internal lid (called a labyrinth lid) structure is used which encourages the evaporated water to condensate and drop back into the battery.
• AGM / VRLA: Absorbent Glass Mat (also known as Valve Regulated Lead Acid) batteries have very similar properties to wet batteries, with one big difference. The electrolyte liquid is absorbed in a fibreglass mesh between the plates. This has a great advantage in that as the liquid is suspended in a material it can never leak out of the battery as can happen with a wet battery. This makes AGM batteries safer to use and handle, and also opens up various mounting opportunities with then being able to be mounted in any orientation, including upside down!
• Gel: Gel Leisure Batteries are unusual, and not offered by many manufacturers. One exception is Sonnenschein Leisure Batteries who produce a large range of high-quality Gel Leisure Batteries. Gel batteries, much like AGM batteries are leak proof as the electrolyte has silica dust added to form a putty-like gel. Gel batteries have far high shock and vibration resistance and are less likely to suffer from electrolyte evaporation. One downside of gel batteries is that if you mistakenly  overcharge them the water can evaporate and can never be replaced.

What about Dual Purpose Batteries?

You may have heard of dual-purpose Leisure batteries. Exide even has a range of Leisure Batteries called Exide Dual. Dual Purpose batteries have both starting and deep-cycling capability, but there is a trade-off in that dual purpose batteries perform adequately at both tasks, but are not a star performer at either duty. These tend to be best used in applications such as a small marine application where one battery is used for both starting the engine and powering onboard lighting etc.

Summary

We hope this article gives you some guidance on how best to choose a leisure battery. If we can be of any further assistance, please feel free to contact us.