Battery Profiling

Deep cycle batteries are used to store energy between generator runs and to provide power to the telecoms loads. Battery life is dramatically influenced by state of charge management, which must follow the manufacturer’s charging profile if battery life is to be maximised and warranties adhered to. The diagrams below illustrate one of the many programmable battery charging profiles implemented by PowerOasis SmartHub Controller. The top chart shows the battery state of charge and the bottom chart shows the corresponding battery current.

During the bulk charge phase (also described as constant current or UI phase) the battery charge acceptance is high and the power system is in current limit, power delivery to the battery during this phase is optimal and limited only by the power source. In the bulk charge phase approximately 80 – 90% of battery charge can be returned.

The absorption charge phase returns the battery to full state of charge, in this phase the battery voltage has reached that of the power system and the charge current reduces. This constant voltage stage of the cycle is less efficient in terms of power return but necessary to fully recharge a battery.

The float charge is required for long term maintenance of batteries on standby application, the charge voltage is reduced and battery current at low residual levels. The float charge is only required where commercial power is available for extended periods.

Battery state of charge is monitored using highly accurate patent pending coulomb counting algorithms to avoid battery damage from undercharging or over-charging. The state of charge, combined with high and low voltage disconnect thresholds, are used by PowerOasis SmartHub Controller to control rectifiers, which govern the power used to charge the batteries.

PowerOasis tests and certify the performance of each battery system and can therefore recommend solutions based on the performance and cost criteria of the telecoms operator.

PowerOasis has undertaken extensive testing with EnerSys and recommends its Eon battery for telecoms applications. EnerSys will provide a higher level warranty when their batteries are controlled by a PowerOasis system.

PowerOasis has undertaken extensive testing with SAFT and recommends its Evolion Lithium-ion battery for long term telecom applications.