How much data do DM Devices use?
Written by Matthew Clark-Massera
Updated at July 16th, 2025
Table of Contents
Disclaimer
Advice is general and partners should conduct their own testing and make an informed decision. It should be noted that Digital Matter supply devices globally, but have offices based in the US, The Netherlands, South Africa and Australia.
Our advice/the content of this article may be biased towards certain regions purely because we have more partner feedback from these regions around what works.
NB: Cat-M1 and LTE-M are used interchangeably in this article, they mean the same thing. Networks like to change names to make things as confusing as possible! However more recently LTE-M is the common term (that wasn't what it was when the networks were first launched!).
Rules of thumb
- Battery powered devices (i.e. Yabby3 and Oyster3) use about 1 - 3MB of data per month.
- Wired devices (i.e. Bolt2, Dart3-BLE and G70-BLE ) use about 5-10MB per month.
The answer really is 'it depends'. We cannot simply look at the record size sent by our devices and multiply that by the number of uploads. Other things contribute to the overall data use, including
- TCP Overhead: Our devices communicate via TCP. TCP is a protocol that establishes and maintains a connection while two parties exchange data. This uses up extra data in sending hellos, acknowledgements, and other messages just as part of the actual connection, before we even send any data. This is can often outweigh the actual message payload.
- Firmware updates
- GPS aiding data. Our GPS devices regularly download satellite information. Using GPS Aiding (or Almanac data on Edge devices) can significantly boost GPS performance, reduce fix times, and extend battery life.
- Device System Parameters. The configuration of the device, like the tracking frequency, will impact the upload size and number of uploads.
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Minimum connection charges typically do not apply on NB-IoT, you're only charged for the data you use, with no rounding up to 1kB, or 2kB for example, like on traditional networks. However, this is not a given, so be sure to check with your SIM provider.
- Consider Vodacom in South Africa. Each new data connection is charged a minimum of 10kB. The device may send less than 1KB on a heartbeat, but it is still charged for 10kB. With hourly heartbeats, this adds up fast. 10kB per heartbeat x 24 hourly heartbeats x 30 days = 7.2MB. That's just on heartbeats. MTN in South Africa charges a minimum of 25kB per connection. That's 18 MB.
Keep in mind:
- Dropped connections also have an effect: each reconnection could be charged the minimum connection charge.
- Grouped/pooled data plans provide some 'breathing room' for devices that may upload more than planned, since there will be others in the pool that use less data that month
With all these various factors, we can make estimates, but the easiest and most reliable way to work out how much data a device will use is to simply insert the SIM, let it run for a while with the desired settings, and then just look at the data usage at the end of the month.
Some Data Usage Tests
GPS Devices (Yabby3, Barra GPS, Oyster3 and Remora3)
We set up a Yabby 3 for 4 x Daily heartbeats. However as it is a GPS device, it periodically downloads satellite aiding data, which dramatically increases the overall data usage.
M2M One NB-IoT SIM card, operating on Telstra's NB-IoT network in Perth, Australia
Key stats:
- Average data usage per heartbeat: ~1.5kB
- Average data usage per aiding data download: 50kB
- Aiding data is downloaded once every 4-6 days, let us call this 5 times in a month.
So, we can provide the following rough estimates for NB-IoT
- 1 update per day: ~50kB for heartbeats + 250kB for aiding data = ~300kB/month
- 2 updates per day: ~100kB for heartbeats + 250kB for aiding data = ~350kB/month
- 4 updates per day: ~200kB for heartbeats + 250kB for aiding data = ~450kB/month
For LTE-M, the min connection will apply on the heartbeats (2kb for Telstra in AU) - so the data usage will be higher.
Differences in GPS Aiding Data download behaviour
We use Sony and Ublox GPS modules in our Standard GPS devices. There are differences in the aiding data payload size and how often they are downloaded between the module brands. A Barra GPS (Ublox GPS) would use more data than a Yabby3 (Sony GPS) using the same tracking settings. The maximum GPS aiding data download can reach almost 100 KB for Ublox GPS-based devices however, these downloads do not happen very often.
Edge Devices (Yabby Edge, Barra Edge and Oyster Edge)
The way in which GNSS and Wi-Fi fixes are obtained on the Yabby Edge is quite different to our other devices. Almanac data is sent to the device but the file size is far smaller, so overall data usage is lower.
A Yabby Edge was configured for 2 x Daily Heartbeats., using a Telstra NB-IoT SIM in Perth, Australia.
Key Stats:
- Each heartbeat is approximately 1-1.3kB
- The variance is based upon how many Satellite/WiFi Access points are found and sent to the server, which changes.
- >1-2 times per month, the almanac is downloaded, which is about 5kB
- The total data usage for the month was 74kB
So this gives us the following rough estimates for monthly data
- 1 update per day 35-40kB/month
- >2 updates per day ~75-80kB/month
- 4 updates per day ~145-150kB/month
Barra Core
A Barra Core was configured for 2 x Daily Heartbeats., using a Telstra NB-IoT SIM in Perth, Australia.
Key Stats:
- Each heartbeat is approximately 1-1.3kB
- The variance is based on how many WiFi Access points are found and sent to the server, which changes
- The total data usage for the month was 62kB
So this gives us the following rough estimates for monthly data
- 1 update per day ~30-40kB/month
- >2 updates per day ~60-75kB/month
- 4 updates per day ~125-150kB/month
Can I get this lower? Can I disable GPS aiding data downloads?
Adjusting system parameters like tracking frequency or features like Bluetooth (BLE scan upload frequency) can help lower overall data usage. E.g, going from 3 min to 15 min in-trip location logging on a battery-powered device can save plenty of data (and battery life!).
Battery Powered - Tracking Parameters
Hard-Wired Devices: Overview of Operation + Logging Parameters
Unfortunately, GPS aiding data downloads cannot be disabled in the system parameters. These downloads use a small amount of data but help improve battery life by speeding up GPS fixes and lowering power consumption.
LTE-M Data Usage, and how do I get a rough, back-of-the-envelope figure?
This is a reasonable question, but it is important to note that this really is not that hard to test for yourself to know for sure!
However, we can work out some figures roughly.
The above tests done on NB-IoT apply to LTE-M, the difference is that most providers charge a min connection on LTE-M. In Australia, with M2M One (Telstra) SIMs this is 2kb - it might be similar for your network.
So, for a battery-powered device, we could estimate as follows:
- Number of uploads per month * 2kb
- +250kB aiding data per month
For example, a device updating 4 times per day would equate to 4*30*2kb + 250kB = approx 500kB per month.
Powered devices depend heavily on how long they spend in-trip - so it is best to do your own test. Generally, for such devices, we are not trying to work out the cost down to the cent.
What about Firmware Updates?
- Firmware updates are not applied automatically; the partner must log in to Device Manager and apply them.So you should not be caught by surprise.
- Generally, they are around 300-500kB in size.
- If you are using a pooled plan, you could update a selection of your devices each month, in a staged process, to stay within your budget.
- While extremely rare - critical firmware updates can happen, where all devices need to be immediately updated. In these cases, it just makes sense to accept the cost/risk of overage charges, or factor this in initially.
- Firmware over the air is possible on NB-IoT, but since the data rate is much slower, it takes very long - leaving the modem on for a long time = reduced battery life.
