The L120CS-D is a combined Power Supply and Battery Charger for small uninterruptible instrument supply applications where 12Volts and 24Volts are required.

Providing both 24Volts and 12Volts in battery-backed systems can be inconvenient and costly. While 12Volts is available in 24Volt battery systems by centre-tapping the two series connected 12Vdc batteries, until now this has been impractical to use because of the different charging requirements of the two batteries.

The L120CS-D dual voltage charger now makes this possible by the provision of true split rail battery charging to provide balanced charging to both batteries even when 12Volts loads are tapped from the battery pack.

Applications include RTUs, dataloggers, remote field instruments and alarm systems where the requirement exists to power both 12Volt radios and 24Volt instruments.

This DIN rail mounted product is ideal for providing 24Vdc power to instrument systems and 12V Power to battery powered radios.

BATTERY MANAGEMENT

During prolonged power outages, the back-up batteries will eventually discharge. If the load remains connected, the batteries can enter their "deep" discharge phase, which can cause irreparable damage to the batteries, and reduce their capacity and life expectancy.

The PTL120CS-D incorporates a low voltage cut-out that disconnects the loads when either battery voltage falls below its low voltage threshold.

The maximum float voltage necessary to ensure full charge, but not overcharge, is temperature dependent for lead-acid batteries. If the installation is in an environment with widely fluctuating temperature, then fixed voltage chargers will either under-charge or over-charge the batteries.

The PTL120CS-D is provided with temperature compensation so that the float voltage to the batteries is held at its optimum value at all times.

DUAL MODE CHARGING

Batteries can be kept on continuous charge as long as the charging current and float voltage are kept below their specified maximum values. The maximum charging current for a battery is based upon the Ampere-hour capacity of the battery. Many conventional switch mode power supplies do not control their maximum delivered current and can cause batteries to be charged from flat with current levels that exceed the manufacturer's recommendation. The PTL120CS-D provides dual-mode charging, with a well defined current limit in boost mode, so that even when the batteries are discharged, the charging current will be controlled.

SYSTEM MONITORING

The PTL120CS-D also provides an AC OK output. This output can be used to detect power failures without the need for an additional mains detection relay.

SAFE MAINS INPUT CONNECTOR

The main input is connected using an IEC320-C5 standard mains connector. This rugged and secure connector provides a safe means for any service personnel to exchange power supplies in the field without the need for a wiremans licence.