Garmin Edge 840 Solar GPS Cycling Computer with Solar Charging, Touchscreen & Buttons

The essentials

The Garmin Edge 840 Solar is built for riders who want more than basic speed and distance. It’s a GPS cycling computer with a touchscreen plus physical button control, designed to help you navigate tough routes, track performance in a meaningful way, and manage training with guidance that’s tied to your current workload and recovery.

One of the most “buy-it-or-not” factors here is the solar charging. On paper, Garmin states up to 26 hours in demanding use, up to 32 hours with solar charging when you ride under direct sunlight (75,000 lux). In battery saver mode, that jumps to up to 42 hours, or up to 60 hours with solar charging under that same direct light condition. The idea is simple: you can ride longer without constantly worrying about charging—especially on daylight rides.

That said, solar charging is naturally dependent on conditions. If your riding is mostly cloudy, indoors, or in shade, the real-world extension may be less dramatic than the headline numbers suggest.

Key features that matter on the road

Navigation is a major part of the Edge 840 Solar pitch, and it’s not just “route guidance.” It uses multi-band GNSS technology for improved positioning accuracy in challenging environments, which can be a big deal when you’re threading through areas with reception issues or complex terrain.

For climbing, it includes ClimbPro climb planning so you can view upcoming ascent and remaining grade while you climb. The useful bit is that you can track effort with the climb plan visible on your device, rather than relying only on a general profile before the ascent.

There’s also a training layer built around your day-to-day sessions. The device shows suggested daily workouts and training guidance on-screen. It’s described as adapting to your current training load and recovery—assuming you’re riding with a compatible power meter and monitoring heart rate. In other words, this is more compelling if your training setup is already “data-driven.” If you don’t have power + heart rate, the adaptive side may feel more limited.

Tech specs

• Brand: Garmin
• Product type: GPS cycling computer
• Display: Touchscreen
• Controls: Touchscreen and buttons
• Solar charging: Included
• Battery life (direct sunlight, 75,000 lux):
• Up to 26 hours (demanding use)
• Up to 32 hours (with solar charging)
• Up to 42 hours (battery saver mode)
• Up to 60 hours (with solar charging)
• Solar energy note (battery saver, daytime rides): up to 25 minutes per hour added with solar under direct sunlight
• GNSS: Multi-band
• Climbing support: ClimbPro (available on each trip, does not require a course)

Everyday use: what it feels like in practice

Imagine you’re planning a ride with a climb-heavy route. You set up the trip, start riding, and during the ascent you can glance at the display to see not just that you’re climbing, but what the remaining grade looks like. That’s the kind of feedback that can change how you pace—especially if you tend to go out too hard early.

Now layer in training guidance. If you’re riding with a compatible power meter and heart-rate monitoring, the device can show training suggestions and adapt them based on your training load and recovery status. It’s essentially trying to turn your cycling computer into a “ride plan + feedback” system rather than a passive stats recorder.

Is it perfect for every rider? Not really. If you only care about logging basic rides or you’re not using power/heart rate, you may not unlock the strongest training benefits.

Who it’s for (and who should skip it)

It makes sense if you want one device that covers navigation, climb support, and training guidance, with solar charging as a bonus for longer daylight rides. It’s particularly attractive if you frequently ride challenging routes where accurate positioning matters, and if you’re the type to follow structured workouts.

It may not suit you if you’re new to GPS cycling computers, prefer the simplest setup possible, or ride without a power meter and heart-rate monitoring. In those cases, you could end up paying for features you don’t fully use.

Also, keep expectations realistic about solar. Direct sunlight helps, but not every ride environment guarantees that kind of light.

Compatibility & requirements

The training adaptation described depends on using a compatible power meter and monitoring heart rate while riding. For navigation and route planning, you can view planning details on your Edge device and also in the Garmin Connect app on your smartphone, depending on how you set up your trip.

Final verdict

If you’re looking for a GPS bike computer that’s more “co-pilot” than dashboard, the Garmin Edge 840 Solar is worth considering—especially for riders who value accurate navigation, ClimbPro climbing insights, and training suggestions that can respond to your load and recovery. The solar charging is a practical advantage for daylight riding, with stated battery gains that are compelling when conditions match.

You should probably pass if you don’t ride with power + heart-rate monitoring or if you want a simpler, lower-cost approach focused mainly on basic ride metrics. And remember: solar benefits are condition-dependent, so it won’t magically eliminate charging in every setting.

Quick FAQ

Does the Edge 840 Solar require a course for ClimbPro?

No. ClimbPro is described as available on each trip and does not require a course.

How long does the battery last?

Garmin’s stated figures depend on use mode and sunlight. The entry lists up to 26 hours (demanding use) and up to 42 hours (battery saver), with solar charging increasing those totals under direct sunlight (75,000 lux).

What does adaptive training depend on?

The training guidance is described as adapting based on training load and recovery when you ride with a compatible power meter and monitor heart rate.

Is solar charging only useful in direct sunlight?

The provided solar battery information specifically references direct sunlight at 75,000 lux, so solar impact will likely vary outside those conditions.