The system is designed to ‘rejuvenate’ new lead acid batteries that have been standing on the shelf for a prolonged period of time. The operation is called ‘priming’ and this will cycle a battery performing a charge, discharge and charge cycle once, which will in layman’s terms ‘wake the battery up’ to increase its capacity to its designed capacity, limiting the effects of battery deterioration during long term storage. This is slightly different to ‘formatting’ which is the ability of a battery to increase capacity during the first few charge / discharge cycles during normal operation. These will be briefly described below. The following information is only typical of Lead Acid Batteries – and is an excerpt from the www.batteryuniversity.com website. (This site is a must read for any battery technology enthusiasts!)
Priming a New Battery
Not all rechargeable batteries deliver the rated capacity when new, and they require formatting. “What’s the difference between formatting and priming?” people ask. Both address capacities that are not optimized and can be improved with cycling. Formatting completes the fabrication process that occurs naturally during use when the battery is being cycled. A typical example is lead- and nickel-based batteries that improve with usage until fully formatted. Priming, on the other hand, is a conditioning cycle that is applied as a service to improve battery performance during usage or after prolonged storage. (Priming relates mainly to nickel-based batteries.)
Lead Acid Batteries
Formatting a lead acid battery occurs by applying a charge, followed by a discharge and recharge. This is done at the factory and is completed in the field as part of regular use. Experts advise not to strain a new battery by giving it heavy duty discharges at first but gradually working it in with moderate discharges, like an athlete trains for weight lifting or long-distance running. This, however, may not be possible with a starter battery in a vehicle and other uses. Lead acid typically reaches the full capacity potential after 50 to 100 cycles. Figure 1 illustrates the lifespan of lead acid.
A new lead acid battery may not by fully formatted and only attains full performance after 50 or more cycles. Formatting occurs during use; deliberate cycling is not recommended as this would wear down the battery unnecessarily.
Deep-cycle batteries are at about 85 percent when new and will increase to 100 percent, or close to full capacity, when fully formatted. There are some outliers that are as low as 65 percent when tested with a battery analyser. The question is asked, “Will these low-performers recover and stand up to their stronger brothers when formatted?” A seasoned battery expert said that “these batteries will improve somewhat but they are the first to fail.”
The function of a starter battery lies in delivering high load currents to crank the engine, and this attribute is present from the beginning without the need to format and prime. To the surprise of many motorists, the capacity of a starter battery can fade to 30 percent and still crank the engine; however, a further drop may get the driver stranded one morning.