TEST: Decathlon FL510 – the affordable front light with StVZO approval impresses with its good illumination of the route. We test the bicycle lights and show what they can do.
Test of the Decathlon FL510 – all information and data about the bike light at a glance
The Decathlon FL510 is a StVZO compliant bike light with built-in battery. At €19,99, it is one of the cheapest bike lights in our best list. The material and workmanship seem correspondingly less valuable, but still neat. The plastic housing is attached to the included handlebar mount using a twist lock and sits there stably and securely. The illumination of the path is surprisingly large and good - but the light itself, at 20 lux, is one of the weakest models in our test field. Decathlon therefore specifies a driving speed of only up to 15 km/h. With IPX4, the bike light is only splash-proof - so users should not leave their bike standing in the constant rain with the lamp mounted.
data sheet
| luminosity | 20 lux |
| light modes | 2 (20lux – 10lux) |
| Lighting time | 3 h – 6 h |
| Charging time | about 2 h |
| charging connector | micro USB |
| Mounting options & adapters | Links |
| performance battery | 750 mAh |
| battery | No |
| Remote Control | No |
| weight with bracket | 78 g |
| StVZO approval | Ja |
| Color temperature | |
| Price | 19,99 € |
What's in the box
The Decathlon FL510 comes on a plastic-free cardboard display with the following scope of delivery:
- Decathlon FL510 bike light
- Handlebar clamp with rubber inserts for different handlebar diameters
- USB-A to Micro USB charging cable
Accessories & Extension
Unfortunately, Decathlon does not offer any other accessories.
Test: The Decathlon FL510 in use
assembly and fastening
The Decathlon FL510 is mounted on the bicycle handlebar using a clamp on a rubber pad. The clamp is closed with a wheel nut and can therefore be installed and removed without tools. Installing the bike light is simple and intuitive - it is ready for use for the first time within one to two minutes. We achieved a tight fit on the thin part of the handlebars using both included rubber spacers. The lamp itself is simply plugged in and rotated 90 degrees, then it snaps neatly into the holder.
To release it, a small yellow lever must also be pulled up. Since the handlebar mount can be rotated, the following problem arises: When you try to loosen it, the mount rotates with you. To prevent this, it must be actively held. This is of course a bit fiddly, especially with gloves. Despite the somewhat delicate-looking handlebar mount, the Decathlon FL510 is comparatively stable and secure; wobbling is hardly noticeable, even on forest paths. When handling in general, wobbling is clearly noticeable.
Service
The operation is quite simple: a rubber button switches on the bike light; Pressing it again switches to the second brightness level. To switch off, press the button for one second. Unfortunately, there is no optical indicator for the button, so it cannot be seen in real darkness. Accordingly, sometimes you are looking for something. The button is difficult to feel, especially when wearing gloves, as it is elegantly and flatly integrated into the housing. If you press too hard while searching, you will move the handlebar mount downwards.
battery & runtime
The user can charge the empty battery via an outdated micro-USB port - USB-C would be much more modern here. The charging socket itself is safely and tightly hidden under a large rubber cap. Decathlon specifies the charging process as two hours. The battery has 750 mAh. At full power with 20 lux you get a running time of 3 hours. The second light level halves the output and has a running time of 6 hours. On cold winter days, as with all battery-operated bicycle lights, you have to expect less. A small LED on the top briefly informs you about the charge level every time you switch. If this falls below 30 minutes remaining running time, the LED flashes red.
The light field of the Decathlon FL510
The light field of the Decathlon FL510 is pleasantly noticeable: compared to some of the competition, the beam of light is less harsh and also illuminates the area immediately in front of the front wheel quite well. The sideways, soft gradient into the darkness is also impressive. This is particularly interesting for winding journeys, as the area being targeted also receives some light. For the distance, Decathlon relies on a spot area with the FL510. This is significantly brighter than the close-up area - but things in this cone are very good. The transition to close range should be a little smoother, but given the low price, that's a high level of complaining.
The 20 lux maximum light output is comparatively dark. So if you want to ride unlit streets or dirt roads at full throttle, you may want to use stronger bike lighting. Therefore, as mentioned, Decathlon specifies a speed of up to 15 km/h. Leisurely cyclists should get along just fine and in a well-lit, urban area it's definitely enough. The second light level with half brightness is only suitable for an illuminated environment, for example from street lamps. Or for steep, leisurely uphills in the dark.
The light levels in direct comparison
The following animation automatically shows the two different brightness levels of the Decathlon FL510.
