The audience for this post are technical engineers and meter installers from power companies and utilities. Meter users are not allowed to exchange the batteries. Opening the battery compartment will lead to tamper.
Not each energy meter has a battery inside, for example, some with simple designs, as required by customers. For smart energy meters, there must be batteries.
What are the purposes for having batteries?
Energy meters transmit data via its network, different from other meters via radio. And there is a real time clock (RTC) inside a meter to collect events. Meters have to work without stop to make data transmission and RTC normal. When power cut off, batteries function as backup power supply.
SuperCap is a capacitor, it can supply power only for 48 hours to 72 hours. Reporting communication data at blackout needs big current to supply, SuperCap then can help the meter work well. At areas with temporary power cut, the application of SuperCap is available.
For a longer time, choose batteries. Especially at the time energy meters are distributed from manufacturers to installation, backup batteries enable their time buffer not to delay, so that data and events inside them will keep in order.
Can batteries be sometimes exchangeable?
Energy meter batteries have two designs in terms of change. One can’t be changed with design life of ten years, same life as the meters. Another is changeable, aim to tariff and other time functions.
The latter kind of batteries install outside the meter cover, and can be changed in hand directly. Unchangeable batteries have a lifetime of common ten years, while changeable batteries have a shorter life, which depends on blackout power consumption, use environment and their own quality. The design lifetime of changeable batteries is eight to fifteen years, but actual lifetime is typically shorter due to environmental influences.
What will happen to the meter when the battery is empty?
For energy meters with changeable batteries, if there are no batteries, something bad will occur. For example, without battery, energy meters with function of time mark will go back to starting time; energy meters with tariff will count in wrong number.
But how do we know the empty battery situation of a remote energy meter, installed in the wild, in particular? The smart energy meter via its network solve this problem due to its function of power source and voltage detection. Once power source and voltage are low, it will alarm and send message to its AMI system if with communication function.
Under regular conditions, it is not necessary to change batteries.
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