Equipment Tests > Batteries

That's why 'deep cycle' batteries were invented. Without getting too technical, deep cycle batteries soak up more electricity and deliver it for longer, making them more suitable for 'house' batteries, for use in camping and caravanning. But, they like to do it slowly. They don't like punching out big current so usually aren't suitable for vehicle starting. In general, they also require longer to recharge. That counts against them for some situations, as most vehicles don't run continuously for the 24 hours or more that these batteries like to fully charge.

What do the numbers mean?
Although most 4WDs - like most cars - have '12V' systems, they actually operate at a higher voltage - into the 14s. Heavy transport trucks often have 24V systems. The energy available in a battery is related to its measurable voltage and 11.5V (when measured at the terminals under no load) is generally regarded as the level that will allow the battery to start the vehicle - just one last time.

'Cold Cranking Amps' (CCA) is the number of amperes (put simply, the amount of effort) that can be continuously delivered by the battery. Just like most other devices, a battery's performance is affected by environmental factors and in this case, this test finds current available at minus 18 degrees Celsius while keeping voltage above 7.2V for 30 seconds. Typically, a standard automotive battery will be rated

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to 430CCA or higher. Most manufacturers - vehicle and battery - specify a minimum CCA rating for a vehicle's battery to reflect requirements in cold conditions although, as with many situations, you can't have too much of a good thing. There's no harm in up-sizing your battery if it is to be used constantly in cold conditions.

'Reserve Capacity' (RC) is the amount of 'fuel' in the battery. It's measured by discovering how many minutes a battery can provide 25A before its voltage drops below a level that will adequately operate the vehicle's engine (typically 10.5V). This test replicates available vehicle driving time with a dead alternator. The number '85RC' on a battery means 85 minutes Reserve Capacity at 25A. The bigger this number, the longer you can drive with a broken alternator or drive belt.

'Amp hours' (AH) is a rating given to deep cycle batteries often used as house batteries for camping/caravanning (or remote area solar-powered domestic housing). It's the measure of how much current is available for 20 hours (some rate at 100 hours; under standard test conditions of 25 degrees) before battery voltage drops to 10.5V.

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