In the realm of
Internet of Things (IoT) and low-power wide-area networks (LPWANs), LoRaWAN®
stands tall as a prominent protocol enabling long-range wireless communication
with minimal energy consumption. If you often get confused about battery life
while deploying a LoRaWAN® Network, then this article is for you.
Since, battery
life is a critical aspect to consider in LoRaWAN® deployments. Efficiently
estimating battery life is crucial for maintaining reliable and sustainable
operations in IoT devices. In this article, we delve into the factors that
influence battery life in LoRaWAN® networks and explore how they can be
calculated, empowering businesses to optimize power usage and prolong device
autonomy.
·
Transmission Frequency:
The frequency at which data is transmitted has a significant impact
on battery life. LoRaWAN® devices can be programmed to send data at regular
intervals or triggered by specific events. Increasing the transmission
frequency will consume more power as the device needs to activate its radio
module more frequently.
·
Radio Interference and Transmission Retries
A radio transmission is a combination of data transmission and a
successful response (ACK) from LoRaWAN® Gateway. The significant amount of
radio interference may have caused much difficulty in data transmission and
listening and results in a longer data transmission. If the LoRaWAN® Gateway
fails to receive and acknowledge data, the LoRaWAN® Sensors or Sensor Node
will retry until they receive a successful ACK from it. This process will drive
negative influence to battery life. To better protect your LoRaWAN® Sensors,
Sensor Nodes, and batteries, try to use channels that have little radio
interference from other devices.
·
Data Payload:
The size of the data payload transmitted by a LoRaWAN® device
affects battery life. Larger payloads require more energy to transmit, leading
to increased power consumption. Optimizing the payload size can help conserve
energy and extend battery life.
·
Transmit Power:
The transmit power level determines the range of communication
between LoRaWAN® devices and gateways. Higher transmit power settings consume
more energy, as the device requires more power to transmit signals over longer
distances. Adjusting transmit power to match the required range can help
conserve battery life.
·
Sleep Duration:
LoRaWAN® devices can be programmed to spend most of their time in a
sleep mode to conserve power. The sleep duration, which refers to the period
when the device remains inactive, plays a vital role in battery life
calculation. By reducing the sleep duration, the device spends more time awake
and consuming power.
·
Duty Cycle Limitations:
LoRaWAN® networks enforce duty cycle limitations to prevent network
congestion and interference. These limitations restrict the amount of time a
device can transmit within a specific time window. Adhering to these
limitations ensures network fairness and efficient utilization of battery
power.
·
Environmental Factors:
The operating environment of LoRaWAN® devices can significantly
impact battery life. Factors such as temperature, humidity, and signal
interference can affect power consumption. Extreme temperatures can cause
batteries to discharge faster, while signal interference may lead to
retransmissions, consuming additional energy.
·
Battery Capacity:
The
capacity of the battery itself determines the amount of energy available for
device operation. Battery capacity is measured in milliampere-hours (mAh) or
watt-hours (Wh). The higher the battery capacity, the longer the device can
operate before requiring a recharge or battery replacement.
Consider using the following generic calculator to
estimate battery life and capacity:
Variables:
C = Battery
capacity (mAh)
BL = Battery
life (years)
Is = Current in
sleep mode (mA)
Itx = Current in
transmit mode (mA)
Irx = Current in
receive mode (mA)
Imeas = Current
in measurement mode (mA) [depends on technology and application]
Ttx = Time in
transmit mode (ms)
Trx = Time in
receive mode (ms)
Tmeas = Time in
measurement mode (ms) [depends on technology and application]
Ta = Total
active time (ms)
Ta = Ttx + Trx +
Tmeas
U = Usable
capacity after accounting for self-discharge (%)
N = Number of
device activations per day
cU = Capacity
after accounting for discharge rate (mAh) = C * (U/100)
T = Milliseconds
per hour = 3600000
cA = Active
capacity usage per day = N * (Ttx * Itx + Trx * Irx + Tmeas * Imeas) / T
cS = Sleep
capacity usage per day = Is * (24 - ((Ttx + Trx + Tmeas) * N / T))
cT = Total
capacity consumed per day = cA + cS
Battery Life (days) = (cU / cT) / 24
Battery Life (years) = days / 365.24
By inputting the
relevant values for each variable into this calculator, you can calculate the
estimated battery life and capacity based on your specific application and
technology.
Understanding
the factors that influence battery life in LoRaWAN® networks is essential for
optimizing power consumption and ensuring prolonged device autonomy. Efficient
battery management plays a pivotal role in achieving sustainable and successful
deployments in the ever-expanding world of LoRaWAN®-enabled IoT.