Ravemen's TR20 uses chip-on-board (COB) technology to create a rear light that pumps out 20 lumens and has a wide range of visibility. It's certainly not the brightest, but it's good as a second light and the mount allows you to use it in a number of different locations.
At only 52mm high and 20g all-in (including the mount) this is a pretty dinky light. Even so, it's fairly bright, with the array of LEDs giving good rear visibility and also decent visibility from the sides.
It's USB-rechargeable and the 200mAh battery contained inside is good for up to 11 hours of light. That's on flashing; if you want the steady high beam then you're only going to get an hour and a half. There are high and low static modes, two flashing modes and one throbbing mode, if that description doesn't make you uneasy.
The mount the Ravemen comes with is designed to go around a seatpost, but with a smaller O-ring it works well on a stay, and with a longer one it's easy to find a mounting spot on most helmets. Compared to some other COB lights like the Cygolite Hotrod 50, the Cateye Rapid X3 and the Knog Mr Chips, the Ravemen light is mostly smaller, less costly and not as bright. Those other lights put out up to 100 lumens (for the Cateye) and are a much better bet if you spend any time mixing it on busy roads.
This Ravemen is better when it's used as a supplementary light. The light weight means it's not noticeable at all when you fix it to the back of a helmet, and the integral clip means it's easy to hook on to a pannier or rucksack.
Rated to IPX4, the Ravemen is rainproof rather than fully waterproof, but I had no issues during testing, which included some typically British summer riding.
Overall it's a handy light to have in the drawer, and it's not very expensive, but it wouldn't be my first choice as a rear light on its own. It'd be great to see a higher-output version that would be better for standalone use.
Good secondary light with a range of mounting options
road.cc test report
Make and model: Ravemen TR20 USB Rechargeable Rear Light
Size tested: Dimensions (light unit): 52mm (L)*18mm (W)*22mm (H);
Tell us what the light is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?
Ravemen lists these features:
1. High efficient COB led with max 20 lumens
2. Quick release designed for various situations
3. Specifically designed lens providing front and side visibility
4. Auto power save and indicator for low battery
5. Built-in Mode memory function
6. Convenient Micro USB charging port
Tell us some more about the technical aspects of the light?
LED: COB LED
Battery: 200mAh/3.7V rechargeable Li-polymer battery
Dimensions (light unit): 52mm (L)*18mm (W)*22mm (H);
Weight (light unit): 15g
Mount size: compatible with φ 24-36mm seat tube
Tell us how the light performed overall when used for its designed purpose
Pretty well: lightweight and fairly bright with a decent run-time on flashing.
Tell us what you particularly liked about the light
Very light, multiple mounting options.
Tell us what you particularly disliked about the light
Not really bright enough to be your only light on busy roads.
Did you enjoy using the light? Yes
Would you consider buying the light? Maybe
Would you recommend the light to a friend? Yes
Use this box to explain your score
If you're looking for a simple-to-fit urban or second light, this will do the job.
About the tester
I usually ride: whatever I'm testing... My best bike is: Kinesis Tripster ATR, Kinesis Aithein
I've been riding for: Over 20 years I ride: Every day I would class myself as: Experienced
I regularly do the following types of riding: road racing, time trialling, cyclo-cross, commuting, club rides, sportives, general fitness riding, fixed/singlespeed, mountain biking, Mountain Bike Bog Snorkelling, track
Dave is a founding father of road.cc and responsible for kicking the server when it breaks. In a previous life he was a graphic designer but he's also a three-time Mountain Bike Bog Snorkelling world champion, and remains unbeaten through the bog. Dave rides all sorts of bikes but tends to prefer metal ones. He's getting old is why.