Tips & Advice

Leisure Batteries – An Introduction

A good leisure battery is an essential component in most motorhomes. It provides power to lights and accessories in the van’s living accommodation without flattening the vehicle battery and leaving you stranded.

The first thing to note is that a leisure battery is not quite the same as a vehicle battery. Vehicle batteries are designed to provide a lot of power for a short time, and then to be quickly recharged. This is what happens when you start an engine and then drive for a while.

Leisure batteries, on the other hand, are designed to be discharged more slowly and over a longer period of time. This is what happens when you camp without electric hookup and use your leisure battery to power lights, television, laptop computers, etc..

There are three main types of leisure battery generally available:

  • Open lead acid: These are the cheapest, and many people believe, the best – traditional lead acid batteries with removable caps and a vent to allow hydrogen gas to escape during fast charging. Note that they will need topping up occasionally and do need venting for safe use. Lead acid batteries are also available in sealed form, where the gases are recirculated and turned back into liquid, rather than being vented. The downside of this is slower charging, but sealed batteries don’t need venting, a possible advantage in a motorhome.
  • Gel: These are basically lead acid batteries in which the liquid has been reformulated as a gel. This has some advantages if you think your battery may be turned upside-down, but I am not sure what the point of it is otherwise. Gel batteries are also much more expensive and charge more slowly.
  • AGM: Another ‘maintenance free’ battery type that is supposed to offer superior performance (for its size) to regular open lead acid batteries. AGM batteries are much more expensive, must be charged more slowly and cannot be topped up.

It may seem as if I am being unreasonably critical of Gel and AGM batteries. However, it should be noted that lead-acid batteries still dominate the worldwide vehicle (and boat) battery market. The reason for this is that they are cheapest and best and no one has yet found a convincing reason to switch to another technology.

Open lead acid batteries (those with vents to allow gas to escape) can be charged faster than any other type and will give good performance at the lowest possible cost. They aren’t maintenance free, however – they do need topping up with distilled water occasionally, especially if charged fast.

The only reason I can see for choosing sealed lead acid, gel or AGM batteries is if they cannot be vented or (in the case of gel batteries) if they will be turned upside down for more than a couple of seconds at a time.

My experience is that open lead-acid batteries work well as leisure batteries as long as they are kept charged and topped up – what’s your experience?

Note: To read more about batteries and charging, have a look at these two links, both from the websites of makers of high quality battery chargers:

2 thoughts on “Leisure Batteries – An Introduction

  • It is true that AGM (absorbed glass mat) batteries are expensive – it reflects both the technology and the manufacturing quality, but of course there are cheaper batteries within any technology. AGM batteries generally have a lower cost of ownership than Gel alternatives, and AGM batteries can be fast re-charged using the correct charger.
    AGM batteries are safer – especially when being re-charged in an enclosed space. Flooded or wet batteries will vent both hydrogen and oxygen during re-charge, especially when being fast re-charged. These gases are explosive and therefore extreme care has to be taken to avoid any risk of explosion or fire. Such invisible, odourless gases can build up over time and may catch out the unwary user.
    Equally, because the sulphuric acid electrolyte is absorbed, should the battery case become cracked, for example in a collision, there is virtually no leakage of acid. This cannot be said for wet batteries, and even Gel batteries if the battery is warm enough, for the acid will leak. Not only is such leakage potentially damaging and even injurious, the battery will also fail. AGM batteries continue to operate even when punctured.
    A further benefit of AGM batteries, one of convenience, is that they can be installed on a side or end thus perhaps reducing the footprint or perhaps making connection more convenient in tight places. It is certainly not recommended that either AGM or Gel batteries can be installed inverted.

    • David,

      Thanks for such a detailed comment. I agree that AGM batteries do have some theoretical advantages – the only problem is that they don’t translate to real-world advantages for the majority of uses/vehicles. This means that it is hard to recommend the extra expenditure for general leisure vehicle use, especially as most motorhomes are used relatively infrequently – just a few weeks a year, in many cases.


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