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.
ABS Motorhome Starter Battery
ABS Boat Starter Batteries
ABS Caravan Motor Mover Batteries
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 a short which may render the battery scrap.
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.
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)
View ABS Leisure range
(EFB) Enhanced Flooded Battery is an addition to the battery market, introduced to aid car manufacturers in meeting emissions requirements in the start-stop cars. Car manufacturer standards require that the batteries last more than 190 cycles at 50% DOD which correlates to 48-58 cycles at 100% DOD. This makes the EFB battery suitable for mid-range leisure uses where some degree of cyclic durability is needed.
View ABS Caravan Battery Page
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.
This method offers another step in endurance, allowing car manufacturers with high emissions to switch off the alternator for longer periods, thereby deeper discharging the batteries and also using the battery power to assist acceleration. 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. Normal manufacturer standards require the battery to get more than 348 cycles at 48% DOD, which translates to 99-118 cycles at 100% DOD.
In the main, AGM batteries are made with a glass, highly compressed, advanced mat, instead of the usual poly-ethylene separatation. This is put between the plates during the making of battery cell packs. Higher compression improves the life and gas efficiency, making the battery maintenance free, unlike standard batteries.
ABS AGM Battery range
CHOSING THE RIGHTLEISURE 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.
Traction and Semi-traction type batteries usually deploy tubular technology or higher density thick plate designed for repeat deep discharge cycling. This method 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.
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.