Battery charge efficiency versus SOC. Problems imposed to quick cycling systems
Charge absorption and charging efficiency of lead-acid batteries both decline rapidly above 85% state-of-charge. In cyclic applications, topping batteries to 100% SOC require remarkably long time and is fuel-cost inefficient for diesel-battery and hybrid systems and almost impossible in PV systems due to restricted daylight duration.
On the contrary, operation in Partial State of Charge (PSOC), is much more fuel-cost effective and has no serious time restrictions.
That’s why, batteries used in harsh RE, telecom and inverter backup systems are regularly cycled at PSOC due to the intermittency of solar generation, an unstable grid or to minimize operating costs of diesel-battery hybrid systems. But operating at PSOC is a potential threat for lead acid batteries that may diminish quickly their overall life and result in frequent and costly battery replacements. (see also the following section)
Our Dynamic Battery Management Concept combines the complete advantages of the fully charged battery for health and longevity and of the partially charged battery for cost efficiency. It is not a simple compromise between battery longevity and cost-efficient operation.
The battery actually is operated in a slight PSOC condition for cost efficiency, while the individual cells are carefully protected against the factors threatening for early degradation (corrosion, dry-out, overheat etc.) and are also periodically desulphated completely in an individual basis, with no sacrifice of active battery plate material. This kind of cell protection extends the battery life even beyond the manufacturers limits.