Leisure Battery Information
Leisure batteries are used in many applications such as Caravans, Motorhomes, Boats, Solar equipment, Camper vans and many more. A leisure battery is basically a rechargeable portable power source.
Lead Acid Leisure Batteries
Lead acid leisure batteries are the most popular selling battery types. They can be very reasonably priced but you need to careful of the quality your purchasing. Most lead acid leisure battery types are sealed units these days so are completely maintenance free but many people get confused with the word “maintenance”. The sealed batteries cannot be topped up with fluid but they do need to be charged regularly (maintained).
All batteries have their pros and cons. The pros with lead acid batteries are that they are very reasonably priced and come in many different sizes and ah (ampere hour rating). The new dual purpose leisure range of batteries are becoming more popular and we highly recommend them simply due to their strong plate design. The cons, they take longer to recharge and they should never be drained less than 30% of their capacity, so you never really get the full use out of the battery. Also you should always charge them at least once a month when not in use.
AGM Leisure Batteries
AGM (absorbed glass mat) leisure batteries are the latest deep cycle technology product. Inside the battery, the electrolyte is held in place by a fibreglass material. This makes the battery non-spillable, completely sealed and maintenance free. These Agm battery types can be drained as low as 10% of their capacity and charge very fast. You will need a charger that an Agm setting for these battery types. The price is slightly higher than lead acid but they do come with longer warranties and if looked after correctly, can last a long time.
These are very popular now on motorhomes with under seat fitment.
Gel Leisure Batteries
Gel batteries are less popular for general public use, mainly due to their high price. They have excellent deep cyclic ratings and can be drained almost completely. These batteries are used in many hospital equipment as they do not emit any gases whilst in use or on charge.
Leisure Battery Info
Unless you are connected to the mains electricity, your 12V equipment in your caravan or motorhome will require a leisure battery. Leisure batteries differs from the standard car battery technology, it is built to handle the patterns and loads that are common in caravans, narrowboats, and motorhomes.
Standard Starter Batteries
A normal or standard starter battery is made to produce a high current to turn over an engine, typically over 1200 rpm down to a temperature of -25°C or -30°C. This is required to overcome the thermal and mechanical resistance of the engine, also, depending on the engine design and standing temperature, requires a cranking current of up to 1000A. The alternator quickly replaces lost battery capacity while the engine is running. A standard lead acid starter battery is designed for standard non start-stop vehicles/cars and are mostly based on the calcium grid technology (low water loss). The design of these batteries focuses more on start-ability than the durability, where the plate count and the plate surface area are optimised to give high cranking capabilities, rather than the cyclic durability.
Low cost, poor quality batteries in this market usually last less than 3 cycles at 100% DOD (Depth of Discharge), that is to say, fully discharged cycles, and normally less than about 20 cycles when compared to the leisure market requirement of about 50% DOD. Mainstream car batteries usually last 25-35 cycles at 100% DOD and more than 65 cycles at 50% DOD. Because of this, standard lead acid starter batteries are not really suitable for the higher cyclic demands that are common to the leisure battery market.
A leisure battery has to provide a steady flow of current over a long period and only gets recharged when the user realises that its Voltage level has fallen substantially. At this point, a recharge must be applied. When left for a long period in a discharged state, or left connected to appliances which forces the battery into an over discharged state, the battery will more than likely, not regain its former state/condition. This condition can lead to the formation of soft shorts which will render the battery unusable.
It is good practice to promote leisure batteries with an indication of the number of cycles that the battery can achieve at 50% state of charge. In the design, increasing the number of cycles given by a battery (life and durability, rather than start-ability) would require:
- Using more lead, usually using higher density active material in the plate construction
- Using more expensive materials designed to work the cell packs at a higher pressure (whilst maintaining acid between the plates)
Conventional lead acid leisure batteries meet the demands of basic level to mid-range applications. Depending on the application, a durability range of 65 to 350 cycles @ 50% DOD is quite common. Investment and developments in micro hybrid automotive technology, which bears similar requirements to the leisure market, has resulted in improved conventional leisure battery durability.
Enhanced Flooded Battery (EFB) technology is a recent addition to the battery market, introduced primarily to aid vehicle manufacturers in meeting emissions control requirements in basic level start-stop cars. Typical car manufacturer standards require that these batteries last more than 200 cycles at 50% DOD which correlates to 50-60 cycles at 100% DOD. This makes EFB batteries suitable for mid-range leisure applications where some degree of cyclic durability is required.
The car manufacturing industry has seen an increased number of sales of high-end start-stop cars that use Absorbed Glass Mat (AGM) technology and this has increased benefits of scale and prices for leisure market uses. Previously, this technology was confined to the industrial and high performance motorcycle battery market. Good quality AGM automotive batteries are also suited to heavier duty cyclic applications, such as frequently operated caravan movers.
Generally, AGM batteries are constructed with a pure glass highly compressed advanced mat, instead of traditional poly-ethylene separators. This is placed between each plate during the manufacture of battery cell packs. Higher pack compression improves the life and gas recombination efficiency, making the battery completely maintenance free, unlike conventional battery types.
The advent of this technology offered a further step in product durability allowing vehicle manufacturers with very high emissions to typically switch off the alternator for longer, thereby deeper discharging the batteries and also using the battery power to assist acceleration (power/passive boost technology). The batteries are better engineered to operate in lower states of charge, which reduces the effect of corrosion to the grids which is more prevalent in conventional batteries operating in low states of charge. Typical vehicle manufacturer standards require these batteries to achieve more than 360 cycles at 50% DOD, which correlates to 100-120 cycles at 100% DOD.
Selecting the Right Leisure Battery
What do you need? Is price important? Is performance important? These considerations lead to a decision to be made by the customer for either a low cost throw-away battery, which is unlikely to provide long-term reliability, or a more robust product that will provide multiple seasons of service. Furthermore, consideration must be given to the level of durability required, for example, a high durability option is best suited for a caravan mover, where low durability options are best suited to powering lighting alone.
A good leisure battery is constructed in a way that optimises the design for a life of repeated cycles and some limited over-discharge service abuse. Some of the limitations of basic lead acid battery chemistry cannot be overcome, but certain design rules and special additives are used to minimise the damaging effects of over-discharge in service. Others technologies with more severe duty cycles are sold in the traction and semi traction markets, but based on normal leisure usage, tend to be an expensive solution.
Semi-traction and traction type batteries typically use higher density thick plate or tubular technology designed for repeated deep discharge cycling. This technology tends to be expensive and out of the reasonable price range for the leisure market in general. It is common for this type of battery to achieve up to 1000 cycles at 50% DOD, but weight and cost are considered a serious limitation for high volume adoption in the current (non-specialist) areas of the leisure and caravan markets.