Introduction
Sunswift Racing is preparing for the 3,000 kilometer Bridgestone World Solar Challenge from Darwin to Adelaide, scheduled for August 24 to August 31, 2025. To keep cars and crews connected across Australia’s remote interior, the team has adopted intelligent link bonding from Ericsson across the race car and support convoy. In plain terms, link bonding blends multiple network paths into one reliable pipe so mission data gets through even when individual links drop or degrade. The goal is simple but critical. Maintain stable telemetry, live strategy dashboards, and crew communications from the first kilometer out of Darwin to the final turn into Adelaide.
What changed
Traditional solar car telemetry often relies on a single modem or a basic cellular router. If coverage fades, data stalls and the strategy team flies blind. Intelligent link bonding changes the baseline. Multiple cellular connections, and potentially satellite backup if desired, are fused at a session level. Bonding spreads packets across available links and heals around failures without interrupting critical flows. The result is higher effective throughput, lower perceived latency, and far better resilience against the patchy coverage that is typical across long stretches of the Stuart Highway. With bonding deployed across both the race car and support vehicles, Sunswift can treat the convoy like a rolling network with phone-grade mobility and enterprise-grade reliability.
Why this matters on race week
The World Solar Challenge is not just a road trip. It is a test of energy management, aerodynamics, power electronics, logistics, risk control, and teamwork under pressure. Every minute, a modern solar car streams a tapestry of signals that drive decision making. Motor current, bus voltage, battery temperature and state of charge. Solar array inputs and maximum power point tracker behavior. Inverter temperatures, aerodynamic drag estimates, chassis vibrations, brake temperatures, tire pressures, and weather data from microstations. A wireless WAN that stays up under harsh conditions lets the strategy team see the whole picture in near real time, compare it against models, and adjust speed targets or convoy spacing before small deviations become big penalties. It also keeps the human side running. Drivers need clear instructions, the chase and lead vehicles need shared maps and hazard alerts, and the media team needs live updates. When a link fails in the outback, you do not want your decisions to lag behind the car.
A quick primer on intelligent link bonding
Link bonding is the practice of combining multiple wide area network links into a single logical connection. The system monitors the health of each path and distributes traffic across them based on capacity and quality. If one carrier’s signal dips or a cell becomes congested, traffic automatically shifts to better paths. When those paths recover, capacity flows back. Modern bonding systems operate at layers that preserve sessions. This matters because cloud dashboards, video feeds, and control channels hate flapping connections. Instead of dropping a session when one modem drops, the bonded tunnel persists. Bonding also enables forward error correction and packet duplication on essential streams. Critical packets can be sent over two links at once, then deduplicated on arrival, which masks jitter and transient loss. This is valuable on rough terrain, near cell edges, or during handovers between towers when the convoy is cruising at highway speeds.
Where Sunswift’s setup likely shines
While each team’s architecture is different, the guiding purpose of bonding in solar racing is consistent. Keep the data moving and the team in sync. A typical deployment places a bonding router in the race car with compact 4G or 5G modems, each paired with high gain, low profile antennas bonded into the vehicle’s aerodynamic shell or concealed within fairings where allowed by rules. The same approach mirrors into the lead and chase vehicles, which run larger rooftop antennas with stronger radios. The bonding overlay spans the convoy so that the support vehicles act as an additional layer of resilience. If the race car is briefly in a coverage shadow, a short-range link to the chase car can carry the data to the WAN through the chase vehicle’s stronger uplink. At the other end of the tunnel, a bonding concentrator terminates traffic either in the team’s cloud environment or in a base station set up in a hotel room or command van. Strategy tools subscribe to live topics or dashboards through that stable end of the pipe.
Inside the telemetry pipeline
Think of Sunswift’s data in three tiers. The inner loop runs on the car and never depends on the WAN. That loop includes battery protection logic, motor control, thermal management, and any autonomous stability routines that the rules allow. It must operate safely even if the outside world vanishes. The middle loop shares operational data with the support vehicles over a local link. Crew see driver vitals, spot anomalies, and handle immediate road safety tasks. The outer loop streams up to the cloud or command environment through the bonded WAN. This is the loop that energizes race strategy, long-range planning, and media updates. For that outer loop, the team will prioritize. Critical signals might be sent as lightweight numeric messages at one to ten hertz, with strong compression and graceful degradation when bandwidth shrinks. Bulk data like high resolution video, lidar traces from test runs, or post-processed weather maps can be throttled or paused without harming safety. Bonding helps here by offering quality-of-service controls. The router can mark life-and-limb traffic so it always wins over nonessential data.
The strategy stack
A bonded wireless WAN is the foundation for a strategy stack that blends prediction and control. At the start of each leg, the team sets a target pace that balances solar input, battery reserve, expected hills, and forecast winds. As the car rolls, live data is fed into a model that updates predicted state of charge at future points on the route. If side winds increase, the car spends more energy holding a straight line and the model shows a deficit. The strategist can respond by trimming speed slightly, changing convoy spacing to cut buffeting, or scheduling a driver swap before fatigue accumulates. None of that works if the data is stale. The whole point of bonding is to reduce stale moments. With multiple links, the latency distribution tightens. A few hundred milliseconds of jitter is not a problem. Ten or twenty seconds of silence often is.
Building for the Australian outback
Connectivity in northern and central Australia is a patchwork. There are long stretches of reliable service and then sections where signals dip behind ridges or fade with distance from towers. Radios must deal with heat, dust, vibration, and strong sunlight. Antennas need ground planes and clean cable runs so they do not pick up noise or leak energy. The best practice here is simple. Use purpose built vehicular antennas that combine cellular elements in a single aerodynamic housing. Keep coax runs short. Bond the antenna ground plane well to the vehicle chassis. Provide active cooling for any modems or routers that sit inside tight compartments. Thermal throttling turns a perfect lab setup into a sluggish field setup. Bonding helps but cannot conjure bits out of thin air. Hardware and installation quality still make the difference.
Redundancy without complexity
Solar teams do not have the luxury of carrying a data center. Every kilogram added to the car or a support vehicle has a cost. That encourages lean redundancy. A common pattern is dual bonding routers in the lead vehicle, with one as cold standby ready to take over if the other fails. In the race car, power draw is precious, so the team might run a single primary unit with a fallback radio that can expose essentials even if the primary fails. Power architectures matter too. The communication stack rides on isolated DC rails that are protected from voltage spikes when the driver accelerates or when the maximum power point trackers swing. Wherever possible, the team avoids single points of failure in connectors, fuses, and harnesses. Simple, labeled looms save minutes during roadside swaps. Fast swaps save positions.
Security that does not get in the way
Security in a mobile setting is about proportion. The convoy needs authentication and encryption, but it also needs to recover quickly if a credential goes bad or a device reboots. Bonded tunnels typically provide encrypted overlay networks that hide the underlying radio changes. That keeps keys in one place and reduces the attack surface. Access to dashboards can be gated with per-device and per-user controls. On race day, teams often run a minimal footprint. Only the devices and staff who must see the screens get access. Everything else is shut down. The objective is not to design a perfect enterprise network. It is to deliver a robust race network that does not surprise the team with a lockout when they are 200 kilometers from the nearest town.
Human factors and crew workflows
The best network feels invisible. Crews do not want to babysit routers while they are handling safety checks, passing maneuvers, and driver changes. Sunswift can lean on presets that select which links to bond and how to prioritize traffic based on location and time of day. For example, during urban starts and finishes, the system might allow higher bitrates for media updates. During desert legs at noon, it may clamp noncritical streams to protect latency for command channels. Crew tablets should display a simple status panel. Green means bonded and healthy. Yellow means reduced capacity. Red means failover only. No one needs a wall of graphs when dust devils are crossing the road. After each leg, the team can pull a simple report. What links were used, how much data moved, and where did the system save the day by healing around a failure.
Testing before the flag drops
Bench tests are not enough. The team should shake down the network on a route that mimics race conditions. Long, hot, and bumpy. Practice starts and rolling stops, then run the convoy at race spacing while changing lanes, climbing grades, and passing heavy trucks. Log handovers between towers and note where dead zones appear. Fail links on purpose. Pull antennas. Reboot a router. Check that critical streams continue and that dashboards show the truth about degraded states. Track power draw in the race car over hours. A setup that looks efficient at idle may grow surprisingly hungry under load when multiple radios transmit simultaneously. Practice crew drills for swapping hardware. Label cases and color code cables. Race week rewards outfits that plan for boredom and chaos at the same time.
What success looks like in the data
A healthy bonded system will show a few signature patterns. Throughput graphs will be smooth across handovers. Latency histograms will tighten as the router learns which links are reliable in each region and shifts traffic accordingly. Packet loss on priority channels will stay near zero even when links individually misbehave, thanks to duplication and forward error correction. When the convoy hits a coverage hole, traffic will dip instead of collapsing, then rebound smoothly. On the strategy side, the team will see fewer periods of stalled dashboards or delayed map updates. The driver will hear fewer repeats of critical calls. And end-of-day reviews will show that energy and pace decisions were made on live data rather than after-the-fact reconstructions.
Fit with race rules and safety protocols
Race regulations evolve, but the underlying intent is stable. Keep competitors safe, protect the public, and keep the competition fair. Communications gear must not interfere with vehicle control beyond what is allowed, and any radio emissions need to comply with national rules. Bonding does not change these fundamentals. It just uses the links more intelligently. Teams still need to verify that antennas are secure, cables are protected from abrasion, and devices are mounted so they do not become projectiles in a sudden stop. The support convoy must maintain legal following distances and safe passing behavior. A reliable network helps here by keeping convoy members on the same page as conditions change.
Budget, power, and weight tradeoffs
Bonded systems do add cost, power draw, and a little weight. The payoff is reduced operational risk. Teams can manage the trade by choosing compact modems and routers designed for vehicles rather than repurposing desktop gear. Antennas that combine multiple elements in one housing simplify installation and reduce cable runs. On the power side, support vehicles are forgiving, but the race car is not. There, the team will hunt for devices with low idle draw and efficient power-saving modes. It is also worth modeling the data plan economics. Bonding does not have to be expensive if the team uses metered plans wisely. Prioritize low bitrate, high value data. Enable bulk uploads only when coverage is strong and costs are lower. Pre-cache maps and weather models over Wi-Fi before each leg so the WAN is not wasted on predictable downloads.
Weather, terrain, and the invisible hand of the wind
Some of the biggest swings in energy budget come from wind. A small headwind increases power demand dramatically. Heat soaks plastics and reduces radio efficiency. Dust can coat antenna surfaces and change their behavior slightly. None of this is dramatic in isolation, but over thousands of kilometers it adds up. A bonded system that monitors real-time link quality gives the team an indirect view of these environmental shifts. If signal-to-noise falls at the same places every day, the team can anticipate it and adjust priorities or convoy spacing to maintain safety and visibility. That is the hidden benefit of building a network that is instrumented instead of improvised.
A day in the life on the Stuart Highway
Picture a typical leg between control stops. Dawn briefing ends, the driver belts in, and the convoy rolls. The race car’s communications stack lights up, the bonding router attaches to two cellular networks, and the overlay tunnel to the team’s command environment goes green. The chase vehicle confirms that camera feeds from the rear are stable and that the pit-to-car voice channel is clear. The lead vehicle calls out traffic and road shoulders. Ten minutes later, the first tower handover arrives as the convoy crests a hill. Without bonding, you might hear the driver ask for a repeat as the voice link gurgles. With bonding, the handover is a non-event. The strategy team watches state of charge tick up as the sun strengthens, then trims the speed target up by one kilometer per hour. By mid-morning, the road gets busy with caravans. The lead vehicle radios a heads up about a long pass ahead. Everyone agrees on timing. The pass completes cleanly because no one was guessing. After lunch, a squall line brings gusts and dust. The car’s energy consumption rises. The strategist orders a small pace reduction and watches the model stabilize around the next control stop. The convoy crosses into a coverage valley, and one cellular link dies. The other link carries the load. The driver never hears about it. By late afternoon, battery temperature climbs and the team instructs the driver to shade the brakes during descents. As the sun lowers, telemetry confirms that the array’s output is fading. The team locks in a plan for the last kilometers into the stop. When the leg ends, the crew knows they made the most of available energy because their decisions were grounded in live data rather than radio luck.
How media and partners benefit
Solar racing is a public stage for engineering. Partners and supporters want to see the story unfold in real time. A bonded network lets the team share selective data feeds and short clips when coverage allows without risking performance. That might mean a simple ticker of speed and location on a website or a curated daily digest with highlights. The key is to separate production media from operational links. The race car and strategy links get priority. Nonessential uploads are buffered and sent opportunistically. Everyone gets what they need, and the engineering mission stays in front.
Contingencies the team should expect
Even the best network hits snags. The plan should assume that a router will lock up once, that a cable will loosen under vibration, and that a fuse will fatigue. Crew checklists catch many of these before they matter. Before roll-out, check antenna tightness, verify bonding status, run a one-minute voice channel test, and send a signed test packet to the command environment to confirm the right tunnel is up. At every stop, glance over the roof hardware and do a quick thermal check with a handheld thermometer. If a device is hot to the touch, shade and cool the compartment before the next leg. Carry spare power leads, fuses, a preconfigured hot spare router, and at least one spare antenna. If the primary unit goes down, swap and keep rolling. A fifteen minute fix beats an hour of chasing intermittent errors.
Training the team for calm execution
Connectivity is a team sport. Drivers should know what to do if the crew loses contact. Typically that means following the last confirmed speed plan, switching to a backup voice channel, and holding position until the convoy reestablishes comms. The lead and chase vehicles should practice radio discipline so critical calls never get buried under chatter. The strategist should rehearse silent-mode procedures for when data stalls, which can include conservative speed targets and a planned rendezvous point if the outage exceeds a set threshold. These habits turn a scary moment into a routine one. Bonding reduces the odds of an outage. Good training reduces the impact when one slips through.
Sustainability and the bigger picture
The World Solar Challenge exists to push clean mobility forward. Reliable connectivity is part of that push because it closes the loop between design and reality. The data captured during a seven day traverse of Australia’s interior becomes a living textbook for the next generation of engineers. It shows where theoretical models matched reality and where they did not. It reveals how small improvements in aero sealing or tire selection change energy budgets by measurable amounts. It informs how future electric road cars might manage energy against wind and grade in the real world. All of this is amplified by a network that captures more complete, less interrupted data. Every extra minute of live, validated telemetry helps teams learn faster and build better.
Practical checklist for race week
- Install vehicular antennas with proper ground planes. Keep cable runs short and protected. 2) Heat test every router and modem in closed compartments. Add ventilation or fans if needed. 3) Preconfigure bonding profiles for urban starts, open desert, and mountainous sections. 4) Cache maps and weather models on devices before each leg. 5) Review daily reports to refine bonding behavior for the next day’s terrain and coverage.
Timing and the road ahead
The event runs from August 24 to August 31, 2025. In the months leading up to the start in Darwin, Sunswift’s network checklist should include hardware burn-in, long-route shakedowns, carrier plan verification, and final operating procedures. The week before race day is for validation, not invention. The dawn of day one is for routine. If the communications stack blends into the background and the team talks about race craft instead of routers, the preparation has done its job.
Frequently asked questions
What exactly is link bonding in this context
It is the practice of combining multiple cellular links and potentially other links into a single logical connection that looks stable to applications. The bonding layer spreads traffic across links, heals around failures, and keeps sessions alive even when a link drops or a tower handover occurs.
Does bonding increase speed or just reliability
Both. When multiple links are healthy, effective throughput rises because the system uses them in parallel. When one link degrades, reliability rises because the other links carry the load. For race operations, the reliability is often more important than peak speed.
Can a solar team run without bonding
Yes, and many have. But the cost is higher risk of blind spots, delayed decisions, and more stressful crew workflows. Bonding turns a patchwork network into a predictable service, which is valuable when you are managing energy and safety over thousands of kilometers.
Is satellite necessary
Not always. Carrier coverage along the route is better than many assume, and proper antenna installs amplify that. Some teams add satellite as a last-resort path for low bitrate essentials. Others rely on multi-carrier cellular bonding alone and design their data streams to tolerate the occasional dip. The decision comes down to budget, power, and the crew’s tolerance for complexity.
How much bandwidth does a team actually need
Telemetry itself is modest. A few hundred signals at a few hertz each can fit in hundreds of kilobits per second. The appetite grows when you add live video and rich mapping. A bonded system allows the team to scale gracefully. Essentials first, nice-to-haves when conditions allow.
Will all this technology distract the driver
It should not. The driver sees a simple dashboard with speed targets, alarms for safety thresholds, and clear voice comms. The complexity lives in the support vehicles and the command environment. Good design keeps the driver’s mental load low.
Conclusion
The World Solar Challenge rewards teams that find robust solutions to unforgiving problems. Connectivity is one of those problems. By adopting intelligent link bonding across race and support vehicles, Sunswift has chosen a practical way to keep data and voice channels stable on one of the longest, hottest, and most sparsely covered race routes on Earth. Bonding does not replace careful hardware installation, disciplined crew procedures, or smart strategy. It amplifies all three. When the flag drops in Darwin on August 24, 2025, the teams that invested in reliable networks will spend less time fighting radios and more time turning sunlight into speed. That is what this race has always been about.