GPS Tracker with LONG battery life – Lasts more than a year


Requirement: 

A transport company wanted to track there concrete walls which they transport all over the country and beyond. These concrete walls are loose equipment and are switched form on truck to another on trailers. So, they needed to track the wall itself instead of the truck.

They were already using a 3G based GPS tracker which use Quectel UC-15 3G module inside it as shown below, 

But they didn’t want to use that because it was expensive and had too many features which were not necessary. 

So, they wanted a simpler device which can run off a battery of its own for a long period of the shipment like 1 year. They wanted to track the walls once in a day and one ping with the location coordinates was enough for the application. 


Challenge: 

The challenge here was to keep the device running for 1 year and wake it up everyday at a particular time and send the location after getting the GPS fix and turn off all the peripherals like GSM & GPS  and go to deep sleep to conserve power. 

Fortunately, the VALTRACK-V2 already had everything what was needed for this application to be accomplished. 

So, what i did was i ripped off the parts that were not needed for the application like Accelerometer, EEPROM, Battery charger, IO Connectors and Transistors and MOSFETS.

The only addition was the battery fuel guage which i added for accurate measurement of current consumption and a SMA antenna connector for GSM. 


Firmware: 

We quickly re-spinned the board and got a few prototype done and since the firmware for VALTRACK was already there, we were able to get it up and running in no time. 

The firmware was written to,

  1. Run the device when the RTC alarm occured at daily 9 AM
  2. Wake up the GSM & GPS
  3. Once the location fix was acquired the location was sent as an SMS to a server
  4. Go to deep sleep after switching off everything

Network: 

We chose SMS as the transport mechanism because we were not using more data and recharging a monthly data credit didn’t make sense.

So the device sends logs to a SMS gateway which is collected in a database table. 

For the network we chose the TELE2 SIM card as they have better coverage in the area. 


Battery : 

We have used these large batteries for extending the battery life. 

 

They are of around 18000 mAH capacity in 1S6P configuration.


Testing & Results : 

Here are the test results and they are quire impressive. 

The device was commissioned for testing in September  and it is running fine so far.
The device seems to be conserving power very well & for 4 months the device battery voltage has dropped by 0.05 volts as shown below from 4.175V to 4.125V.

This assures that the device can easily run for a year and probably more. Hoping for the best.

Fore more details, watch this video,

 

Also see :

 

 

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