Battery Life on IoT Long Range Wireless Vibration Sensor


#1

IoT Long Range Wireless Vibration And Temperature sensor is purchased. According to the battery table in your web page, 34TPH in 1 year battery life is possible. However, only 3 months battery life is found based on 34TPH. When the battery voltage reaches ~3.0xV, it drops rapidly in a week. Any idea?

FYI, we are using premium Lithium batteries.


#2

Hi,
Are you using L91 batteries ?
after reaching 3V it will reach around 2.8V real quick and will stay there for months and then again will drop and stay at the next voltage.
Here is a typical battery behavior graph.


#3

We are using Energizer Ultimate Lithium™ Batteries (https://www.energizer.com/batteries/energizer-ultimate-lithium-batteries). When it reaches 3.0x v, it drops rapidly in a week.


#4

@davidfungf, I’m a fellow customer.
What sleep time are you using for this sensor?
What # of retries are you using?
I have the same sensor but haven’t had a chance to start testing it yet.

The L91 Lithium Battery should behave exactly as @Bhaskar describes.
At 1.4V per cell (2.8V in the 2S2P pack), they are close to being depleted.

My initial guess is that your sleep time is why you’re seeing 3 months of battery service.


#5

Here is my setup parameter under the windows configuration tool. Other parameters are default value.

Set Delay is 300 second
Set Power is 1


#6

whats the surrounding temperature/weather conditions and is there any radiation in near by area ?
can you share the battery part number ?

Thanks


#7

The surrounding temperature is 40 °C~48 ‎°C.


#8

temp could be an issue


the most ideal temp is around 20’C.

is the temp constantly 40-48’C or once in a while ?


#9

Capacity rating is reduced at freezing and below.
I wouldn’t think 40°C is the problem.
I’ve performed several discharge profiles for the L91 at 100°F (38°C) that always resulted in higher capacity than the datasheet.

@Bhaskar, You may remember a couple years ago I experienced shorter battery runtimes for a sensor that had marginal Mesh Coverage. The combination of the controller retries and the XBee retries compounded and used several days worth of capacity when the Mesh Network couldn’t be reached over a few hours.
That location had poor Mesh Coverage, and local RF interference at certain times of the day that was hard to identify.
@davidfungf, it this possible for your installation ?


#10

The sensor is placed on top of the escalator’s motor and the receiver is nearby the sensor. The motor is placed in a closed environment. Attached please find the photos for your ref. Any idea?



#11

@davidfungf, this is a long shot :thinking: , but here goes:

@Bhaskar, do you think the magnetic field on top of that large motor could be causing problems with the board’s coil (we saw similar symptoms when I had a magnet in the center of the enclosure years back, before I knew better).
If so, the Industrial version with off-board sensor may be a better choice for this particular application?


It also gets the radio away from the motor.


#12

yes magnetic field could cause the issue.

we have installed one of the sensor in our freezer( temperature is around -21’C).
its been around 15+ weeks and so far its been working great and the battery is staying at around 3V. the sensor is sending data after every 5sec.

@rfontaine If the battery works at high temperature it means temp cant be an issue. it could be the installation environment.

@davidfungf could you install one of the sensor in a room environment and see if the battery still drains.


#13

Thank you for your information. We take time to observe the sensors battery life where installing in the normal environment.