Solar-Powered GPS Trackers vs Battery-Powered
All electronic and IoT devices (GPS trackers included) require some form of power to operate.
Traditional fleet management devices such as our Bolt, Dart2, and G120 are plugged directly into a vehicle’s OBD port or wired to a power source, usually the vehicle’s battery, to provide real-time tracking when the vehicle is on.
Other assets, such as trailers, containers, and bins are usually non-powered – they do not have a readily available power source that we can plug into. For these types of non-powered asset tracking applications, an alternative power source is required. Generally, in the IoT asset tracking space, we see two power sources utilized – solar and battery-powered.
The Problem(s) with Solar-Powered GPS Tracking
The assumption with a solar-powered GPS tracker is that the sun will be able to provide limitless energy for many years and as a result, is a more sustainable option as compared with devices that are powered by primary cell (non-rechargeable) batteries.
The truth is a bit more complicated.
LiPo’s Limited Shelf Life
Just like the solar panels you may have on your home or farm, solar-powered GPS trackers feature solar PV (photovoltaic) panels to capture sunlight and convert this energy into current electricity.
We don’t fancy ourselves astronomers here but clearly, for at least half of any given day, there will be no sunlight!
To provide a constant power source (including at night) the solar panel must be used in conjunction with a rechargeable battery, usually Lithium Polymer (LiPo), which is the same battery type used in most smartphones today. The solar panel will provide a voltage when sunlight is on it to recharge the LiPo battery, which then in turn powers the unit.
Though advancements are being made in LiPo battery technology, these batteries still have a limited shelf life, a limited number of charge cycles, and they can be expensive.
Depending on what features the solar-powered GPS tracker supports and how many times a day it is reporting, the LiPo battery may also have to be physically plugged into a power source to fully recharge, and typically, after 2-3 years of this cycle, the LiPo battery will need to be replaced completely. This is of course dependent on how often the device is reporting and how much power is required, but we see similar degradation in our smartphone batteries – a brand new phone holds its charge much longer through the day than a 2–3-year-old smartphone.
So the “limitless energy” we tend to associate with solar power is, actually, quite limited by the shelf life of the LiPo battery it requires to function.
In addition to the limited shelf life of LiPo batteries, solar panels themselves are expensive, and they degrade over time. Though this degradation tends to happen at a much slower rate (1% – about 1.5%/ year), different weather conditions, temperatures, and uneven solar irradiance levels can all affect the performance and longevity of the solar panels themselves.
Eyes on the Sky
A more obvious limitation of solar-powered GPS trackers is the fact that they need the sun, therefore require view of the sun to operate. Solar-powered devices are then generally installed on top of assets where they always have a clear view of the sky. This installation location, unfortunately, makes solar-powered trackers extremely difficult, if not impossible, to hide on, under, or even inside of an asset – they just won’t work.
It goes without saying (but we will anyway) that if your GPS tracker is stolen or removed from your asset, it’s not doing the job it was designed to do.
View of the sky in this case would also apply to the asset itself. A trailer for example may be moved under cover or even indoors, which means the solar-powered device may not work or recharge as effectively.
In addition to a higher chance of asset theft, installing solar-powered devices on top of assets without protection also means the solar panels are more likely to be covered in dirt and other organic matter, which of course impacts power production.
Digital Matter’s legacy solar-powered tracker the G52S shown when exposed to environmental elements for several months.
Having to manage and charge your tracking device once it has been installed is probably not a huge inconvenience if you are tracking one or two assets a few times a day that don’t venture very far away from your home or office. In these applications, a solar-powered device is a great and viable option!
But no business wants, or may even have the capacity to, coordinate “recharge cycles” across hundreds or even thousands of assets, often located across different worksites, regions, or countries!
The fact is solar-powered devices require more hands-on device management than a primary cell battery-powered device that lasts longer. When you are tracking many assets, a “deploy once” device that requires minimal interaction once installed will reduce the total cost (time, expenses, and even environmental impact) of device ownership.
Since when are we Solar-Panel Experts?
In 2014 we launched our first solar-powered GPS tracker, the G52S.
While this was an innovative product for its time, advances in battery technology have led to this product being superseded by our range of battery-powered GPS trackers which operate on user-replaceable Alkaline, Lithium, or LTC batteries, depending on the device.
The G52 Solar’s rugged housing and built-in solar panel allowed the device to monitor and track assets in harsh and remote environments, without the need for an external power source.
As we started exploring the use of primary cell batteries in our devices back in 2016 with the launch of the Remora 2G/3G, it was immediately evident how relying on solar power 1) significantly limited the functionality of our devices and 2) was much more expensive to produce with more components – solar panels, charging circuitry, etc.
In recent years we have seen significant improvements in the quality, capacity, and performance of primary cell batteries.
Combining these batteries with advanced and flexible firmware features and strong hardware design has enabled us to produce industry-leading, battery-powered devices like the Oyster2, Remora2, and our newest tracker, the Yabby Edge, with fewer components and at a lower price point.
The Oyster2 and Remora2 can be fitted with Lithium Thionyl Chloride batteries, which:
- Contain stacks of energy – you can find 18Ah per D Cell battery for the Remora2
- Have extreme temperature tolerance, -40 to +80C is typical
Some typical battery lifetimes for our devices:
- 2 years at once hourly location updates
- 10 years at once daily location updates
- 3 years at once hourly location updates
- 12 years at once daily location updates
- 5 years at once hourly location updates
- 10 years at once daily location updates
- 3 years at once hourly location updates
- 7 years at once daily location updates
Thanks to such advances in battery technology as well as low-power IoT asset tracking components, any of our battery-powered devices dominate over solar-powered devices like the G52S.
Even with the sun’s energy, the internal LiPo batteries in the G52S will need to be replaced far more frequently than the D cells in the Remora2.
In addition to localization, our battery-powered device range also supports features such as Movement-Based and Adaptive tracking (automatically increasing the device’s reporting rate based on movement and entering sleep mode at rest) as well as Recovery Mode (switching to live-tracking in the case of theft). These features can be power-intensive and depending on the state of the charge of the LiPo battery, may not be achievable or even supported on solar-powered devices.
Our battery-powered devices also don’t use proprietary, impossible-to-remove batteries (when’s the last time you replaced the LiPo battery in your smartphone?). Instead, we opt for user-replaceable AAA, AA, C, or D cell batteries, which makes it simple to swap them out and continue using the device for many years to come.
Conclusion: Solar-Powered vs Battery-Powered
When researching and deploying asset tracking solutions, it’s important to consider the total cost (financial, time, and environmental impact) of device ownership through its lifetime. Where solar-powered solutions are a fantastic fit for many IoT applications, in asset tracking applications we have found primary cell battery-powered devices offer better performance and longevity, require less hands-on maintenance and management, and are able to support important features like recovery mode and movement-based events.
For more information on our battery-powered asset tracking solutions get in touch with a specialist today.