The Garmin Edge 840 Solar sits neatly in the middle of Garmin’s expansive range of GPS computers, offering a full suite of training and navigation features in a smaller, lighter shell than the brand’s supersized flagship models. It is a high-performance head unit that is easy to live with day to day, but the headline solar charging technology will not be equally useful for everyone.
I have been using the Edge 840 Solar across the UK and abroad for several months, from long solo training rides to travel trips and commutes. It is an incredibly capable computer, compact and packed with features, though the Solar aspect has proved more of a curiosity than a revelation.
Bottom Line
The Edge 840 Solar is one of the best-balanced computers Garmin makes. It is powerful, compact, and thoughtfully designed. It delivers excellent navigation, comprehensive training metrics, and a comfortable size that does not dominate your cockpit.
However, the solar charging function is only worth paying for if you ride in bright, sunny conditions or spend days at a time without access to charging. In typical British weather, or for riders who plug in after each ride, the Solar premium adds cost without much benefit.
Design and Aesthetics
Garmin’s packaging is as complete as ever. You get an out-front mount, O-ring stem mount, lanyard, cable, and manuals. The unit itself feels sturdy, with the usual black casing, silver Garmin logo, and a subtle red solar strip framing the screen to show off its Power Glass charging layer.
At 87g and measuring 57.8 x 85.1 x 19.6mm, it is compact and sleek, identical in size to the Edge 540 but with more features including a touchscreen and 32GB of storage. Compared to the chunky Edge 1040 Solar or newer supersize computers like the Wahoo Elemnt Ace, the 840 feels refreshingly discreet.
Build quality is excellent. The screen is bright enough to read in direct sunlight, even if it lacks the ultra-crisp sharpness of the latest Edge 1050. The port cover is sturdy, and the waterproof rating (IPX7) means it is more than capable of surviving British rain and winter grime.
Setup is simple. Scan a QR code, pair your phone via Garmin Connect, and your existing profiles and sensors transfer automatically. The touchscreen is responsive, but Garmin’s physical buttons remain brilliant for mid-ride use, especially in gloves. I often found myself scrolling pages using the left-side buttons, which felt faster and more reliable on bumpy roads.
Performance
Garmin’s long list of features can feel overwhelming at first, but once configured, the Edge 840 Solar runs like clockwork. It supports ANT+, Bluetooth, and Wi-Fi, pairing instantly with heart-rate straps, power meters, and smart trainers.
Navigation is where the unit shines. Routes loaded from Komoot or Garmin Connect display clearly, with accurate prompts and quick re-routing if you stray off course. I tested it both in the UK and on unfamiliar roads in Italy, and the Edge 840 Solar never missed a beat. It is quick to pick up a GPS signal and handles detailed mapping smoothly, despite the smaller screen size.
ClimbPro remains a brilliant feature for pacing unknown climbs, automatically displaying gradients, distance remaining, and ascent figures. The unit also supports hazard reporting, music controls, and smart notifications if you want to stay connected mid-ride.
Battery life is solid, around 32 hours in regular mode and up to 60 in Battery Saver. Solar charging adds small gains depending on the weather, but in Britain, those gains are minimal – a few extra minutes rather than hours. During testing in Italy under clear skies, it fared a little better but still did not dramatically extend runtime. Riders in sunnier climates may find more benefit, but for most, plugging in a USB-C charger after each ride remains simpler and faster.
Screen clarity is good, but not exceptional by modern standards. It is bright enough for all conditions and handles mapping well, though it cannot quite match the vivid display of the Hammerhead Karoo or Garmin’s latest flagship 1050.
Value
At £449.99 / $499.99 / €549.99, the Edge 840 Solar is firmly in the premium GPS bracket. It is cheaper than the 1040 Solar and similarly priced to the Hammerhead Karoo, but noticeably more expensive than the excellent Wahoo Roam.
If you are drawn to Garmin’s ecosystem and value deep training features, integration with third-party apps, and reliable performance in a compact body, the 840 Solar makes a strong case for itself. But unless you regularly ride in hot, bright conditions, the Solar upgrade offers limited real-world advantage over the standard Edge 840, which saves a decent chunk of cash.
Pros and Cons
Pros
- Compact and lightweight yet feature-packed
- Excellent mapping and re-routing
- Reliable touchscreen and physical button combination
- Strong sensor compatibility and connectivity
- Great battery life without Solar assistance
Cons
- Solar charging is of limited benefit in dull climates
- Screen brightness is slightly dated compared to newer models
- Pricey compared to the standard 840
- Interface still busy for riders who prefer simplicity
Conclusion
The Garmin Edge 840 Solar is a genuinely impressive piece of kit. It takes the best of Garmin’s top-end computers – mapping, training tools, connectivity – and packs them into a smaller, more manageable body. It is a joy to use on the road, simple to live with, and delivers everything most cyclists could need.
But unless you regularly ride long distances under blazing sunshine, the Solar feature will not transform your experience. For many riders, the standard 840 offers identical performance for less money.
Still, in an age where bike computers are getting ever larger and more complex, the 840 Solar feels like the sweet spot. Small enough to disappear on your bars, powerful enough to do everything you ask of it, and reliable enough to trust on any ride.
