W
IRELESS
A
MBIENT
L
IGHT
S
ENSOR
C
OPYRIGHT
©
2019,
R
ADIO
B
RIDGE
I
NC
.
W
IRELESS
A
MBIENT
L
IGHT
S
ENSOR
P
AGE
5
OF
14
4.
B
ATTERY
L
IFE
The sensor uses a lithium non-rechargeable battery and is capable of 200,000+ total messages
depending on the wireless standard and usage. For an accurate estimate of battery life, please
refer to the “Sensor Battery Estimator.xlsx” spreadsheet on the Radio Bridge w
ebsite. This
spreadsheet combines usage information such as average number of messages per day and
estimates the battery life for a particular sensor.
The power required for a message transmission is much greater than the “sleep current” (the
power consumed when the sensor is inactive) for high power radio technologies such as
LoRaWAN. This means that the battery life for most sensors is primarily dependent on the number
of transmissions per day.
Different battery types will deplete over time with different voltage profiles. For instance, a
lithium battery will maintain a relatively high voltage for the life of the battery and then
experience a rapid drop near the end, whereas an alkaline battery will experience a more gradual
reduction in voltage over time. Radio Bridge sensors are shipped with lithium batteries, and these
are recommended when the battery needs to be eventually replaced.
Temperature also plays a role in battery life. The battery life estimates in the online spreadsheet
assume room temperature, but temperatures close to the maximum and minimum ratings will
have a negative impact on battery life. For example, battery voltage tends to be lower in cold
temperatures and the internal circuitry needs a certain minimum voltage to operate properly
before it will shut down. Thus, battery life will tend to be shorter when running the sensor in cold
environments.
The battery voltage is reported by the supervisory messages as well as a low battery indicator.
See the section on Message Protocol for more detail.
Refer to the spreadsheet “Sensor Battery Estimator.xlsx” on the Radio Bridge
website for specific battery life estimates.
Battery voltage will be lower in cold temperatures and thus battery life
will be reduced in cold environments.
