We get regularly asked what is a good battery for this or a good battery for that, since we are coming into the summer, it is very likely that many of our customers will get enquiries for leisure batteries. A brief understanding of these types of batteries is of great importance as all leisure batteries are not made equal !
What is a Leisure Battery ?
This is a general description used for batteries that are meant for Leisure applications such as supplying domestic power in Caravans, Motorhomes, Camping, Sailing, Marine etc. Some of these are also perfectly suitable to supply dual power requirements, starting and domestic power. Leisure batteries are constructed to withstand deeper discharges and recharges than normal batteries giving them a much better life in domestic power applications where they can be discharged and recharged a number of times.
These now tend to be available in a variety of guises, Accessible Flooded, Open Vented, Sealed, Maintenance Free, Flooded, Flooded with Glass Matt Separators, AGM, GEL. I will not go into the detailed description of each, as the terms used and actual battery types can vary depending on descriptions given by the manufacturers and wholesalers.
Some of you will ask… “.. but which are the best ones ?” this is totally dependent on use and installation type. We would normally define the best battery as the most suited to an application giving a good life span and a comparatively low total cost of ownership. In most cases a good quality Flooded/Wet Cell Leisure battery is the most cost effective solution, in more advanced/specialist installations this may require a AGM VRLA battery.
What must also be remembered is that they are “Leisure” Batteries, if a need is for an industrial deep cycle application is required, then a semi-traction/traction or industrial battery needs to be installed. Fitting a leisure battery to such an application will lead to early failure and be a false economy.
What size/type of battery is required ?
In most cases this will be limited by the size of the battery box, although it is always prudent to understand the application and use the battery will be subjected to. A caravanner who uses his basic caravan 2 or 3 weekends a year and only goes to sites with mains hookup will have a very different requirement from a user which might regularly spend up to 3 weeks on the road a number of times a year in isolated sites with a Motorhome with every conceivable extra on board.
In the first case a basic 70 to 85Ah Leisure battery would normally suffice as the power requirement and frequency of use is very low. However in the later situation the user may require more than one larger battery (they can go above 200Ah) and possibly also more advanced technologies such as semi traction or AGM types.
What size of battery might be needed ?
There are a number of online "calculators" offering help with this
Some of you may gasp at the size of the battery that the calculators available on the internet might recommend. It must be remembered that all calculators must build in a safety margin against too heavy a deep discharge to balance battery capacity and longevity of the unit. Smaller units than recommended “could” work but you will be sacrificing lifespan and risk running out of power.
Cost Vs Longevity
Most people associate cost with the initial purchase price of a battery, however the most important consideration should be total cost of ownership. As it is clearly a much more financially astute decision to buy a battery that costs £120 that last 4 years as opposed to a battery that cost £80 that lasts 2 years.
People also sometimes wrongly associate longevity with “headline” power ratings on the battery, surely a battery with a 110Ah label should last longer than a battery with a 75Ah. If the technology in manufacturing and the use and maintenance is the same, I would agree. Although this is not normally the case, a badly constructed cheap budget 110ah labelled battery could last considerably less time than a high quality proven and well constructed 75Ah in the same application.
How flat can I discharge a Leisure Battery ?
It is generally recommended to not go beyond 50% of the rated capacity for a flooded battery but you can go to 75% capacity of an AGM battery to get a reasonable life span. These figures are only guidelines as different brands and different types of constructions will effect these figures. You can of course discharge the battery more, but this will lead to a much shorter life span.
Warranties can have a considerable effect on the direct and indirect choice of the user. Warranties on Leisure Batteries tended to be 1 to 2 years and only against manufacturing defects. Battery warranties are not a guarantee of lasting the prescribed time as type of usage of a battery can considerably change the lifespan. Being informed what is covered and what is not covered under the warranty and the procedure, can only be a good thing so asking when buying is a good idea. Warranties can be especially problematic with Leisure batteries due to their seasonality and type of use, leading to possible non use for 6 to 8 months of a year where sulphation can settle in and cause early failure but is not a warranty issue. A good trickle/maintenance charger can solve that problem