Is there a Battery in a 2WT-B Photoelectric i3 Sensor?

There is no battery in the System Sensor 2WT-B photoelectric smoke detector. This 2-wire, low voltage, smoke detector gets its operating current from the alarm panel to which it is connected. When AC loss occurs, the panel's backup battery will provide power for the detector.

In most areas, building codes now require that 110 Volt AC interconnected smoke detectors be installed throughout newly constructed homes. These smoke detectors get their power from the building's electricity, and they are usually set up so that if smoke enters one sensor, they all sound. These smoke detectors will each have a battery, since they would otherwise be useless in the event of a power failure. The only real drawback to these smoke detectors is that they can't directly interface with your low voltage alarm system, and, in most places, mixing high voltage and low voltage devices is not allowed by code.

The 2WT-B is a low voltage (12 - 24 Volts DC), 2-wire photoelectric smoke detector with a fixed temperature (135 degrees Fahrenheit) heat detector built in. It is both powered by and wired to an alarm panel, such as the Vista-15P, 20P, 21ip, the Vista-128BPT and the Vista-250BPT. The 2WT-B does not have a built-in sounder. It must only be connected to a compatible 2-wire smoke zone. On the panels mentioned above, this is Zone 1. Only Zone 1 will provide the necessary current required to allow the 2WT-B to operate, and for this reason, you should check to verify that any panel, other than those mentioned above, will support these detectors. Compatibility is listed by the manufacturer, and, in addition to showing compatibility, they will also show how many smoke detectors can be supported per panel. Per Honeywell, all the panels mentioned above will support up to 16 of these smoke detectors on Zone 1. Since the smoke detectors are being powered by the alarm panel, in the event of an AC Loss, the panel's backup battery will power the device.