REVIEW: CB SEEN City Slicker Twin LED 500 Lumen, Rear Bike Light

Skyraider59

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[h=2]REVIEW: CB SEEN City Slicker Twin LED 500 Lumen, Rear Bike Light[/h] This is part of a combo set of the City Slicker which has been sent to me for review by C&B SEEN, a small UK company based in Kent.

Please note that despite the fact that this light was not purchased by myself, my review is done under the same format as the one I purchased.
In my reviews, I try to expose the light's weaknesses and strengths while being fair to its specs. There is no comparison to other products unless stated.
My reviews are done with other riders in mind who may be thinking of purchasing the same light.
The lights I review are not always a reflection of what I prefer or ride with. All I am doing is trying to give you an unbiased opinion of the product I have tried/reviewed here in the UK.


What's in the box
The City Slicker 500lm rear light is supplied in a blue display box with a viewing window to see the product.
The packaging is identical to the one used on the City Slicker front light which I have just reviewed.
They have now improved their user manual which comes in a neat tri-folded coloured instruction booklet.
Inside the box is the lamp unit with a pre-attached quick release clamp, a micro USB lead and rubber spacers for the clamp.





Initial overview and feel*
The City Slicker rear bike light takes the form of a short twin barrelled light, with a big window showing the two LED. The light feels sturdy as it is made of anodized aluminum and has side cut outs for rear and side illumination.





The USB port is on the back panel and is protected by a rubber grommet. The light, like the front one, is charcoal black with white etching for their logo and name.




The optic/lens appears to be made of plastic and are held in place by two hexagonal screws.

The body is plain with shallow groves in the centre and all angles are rounded.*

The switch has a built in battery warning light using the well established traffic light method green, orange and red.



The battery is accessible via the removal of the two rear Hex bolts and panel. My bike 2mm Hex tool fitted the bolts . For longer rides you can carry a spare battery if required.
The light's fixing clamp looks and feels sturdy and used the o ring method to attach the slicker to the seat post


Manufacturers Data (latest)
With regard to the materials used on the City Slicker, not a lot of data is shown on the C&B SEEN website or is given in their instruction manual.
The body appears to be made of anodized aluminum with the optic/lens made of plastic.
The light is waterproof to IP65 standards (to be confirmed).
The battery used is CB SEEN own labeled CR123A rechargeable /16340 3.7v 800mAh.
On their web sites the LEDs are advertised as XM-L L2
On the instruction manual, no reference is made to the LED used but I believe them to be the Cree XLamp XB-D 2.5x2.5mm Red color LEDs on my sample.







Settings
The light has 4 modes - Economy, Pulse, High, Low.
To switch the light on hold the button down for 2 seconds. The light will come on initially in Economy which is a flash mode. Single clicks will then cycle the light through Pulse another flashing mode and then to the two steady modes. They are no indications of the output of the steady modes, but I think it would be fair to assume that the high is their 500 advertised lumens.
Hold button down for 2 seconds to turn light off.



Riding with CABS-1200*
*Like all rear lights it is always difficult to see how good they are unless you are behind! When I pass a cyclist on the road, I always check how visible their lights are and try to spot what make they are.
The main problem with rear lights is that cyclists often neglect them riding with rear lights glowing faintly. In my mind they are as important, if not more, than the front one. They cover your back where you cannot see!*
So you need them to be bright. With the City Slicker rear, this will be easy as it is USB rechargeable, and if you have not got a computer or a phone charger available, you can swap the battery.
I know regulations are a little different worldwide, but I would advise any cyclist here in the UK to have two rear lights one in steady mode and another in flash mode.
The City Slicker has been tried during my commute at night. The City Slicker rear has a massive advertised output of 500 lumens which is very bright.
Regarding the mounting instruction supplied, I believe them not to be 100% relevant to the rear light as they talk about adjusting the angle of the clamp on the bar to avoid dazzling oncoming drivers.
Regarding the mounting of the light on your seat post there is NO vertical angle adjustment. You can fit the light as far up or down as you want on your seat post but the angle of the light is determined by your seat post angle.*
This is not a bad thing as it will prevent cyclists having them pointing directly at the following traffic. This implies to me that the light works in a different way and when you see it in action, it does, The Slicker rear produce a bright light visible a long way away but also created a red halo behind you rear wheel. For those like me who have a mud guard you will find that the very bright light bouncing off it creates the impression of a secondary light effect, (see my photos).





As mentioned earlier, you can swap the battery for a replacement one if you find yourself away from a computer or a mobile phone charger when the battery is running low. A 2mm Hexagonal tool will be required. I would recommend extreme caution while doing this on the side of the road because if the small screws were dropped you would have trouble finding them! Do look at which way the battery is fitted as there is no indication of polarity, I would strongly advise the user to mark the positive side.

Trying to replicate what the eye sees at night via photos is not easy, so to help with your perception of the light performance here are the setting used during the beam shots.*
Canon PowerShot SX320HS
Manual setting
ISO: 100
Exposure: 1.6 seconds
Aperture: F4.0
Focus: Manual
White Balance: Daylight
Quality: Jpeg High







You can clearly see the red halo on the ground





Difficult to film with so little light, the light is much brighter that in the video, the photos specially with the 4 second exposure are closer to what the human eye can see.


Pros:
Very bright creating a red halo on the road behind you
Side windows
Good run time
Easy interface
USB rechargeable
Battery replaceable
UK warranty (2 years on light and 6 months on battery)


Cons:
Can only be mounted to seat post
No quick release devise to replace the battery
No indication of polarity in the battery cradle

RRP £34.74 plus UK postage (09/01/2015)

I believe that for the moment they are only retailed in the UK.

Skyraider 59
 

angerdan

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You are right, the rear light is at least as much important than the front light.
Unfortunately, this one has one common drawback: low to nearly no side visibility due to the low horizontal beam angle.
Especially in city traffic, this can be very important.

500lm are impressive. If it really are 500lm.
If CR123 is a good option if 18650 would be more common?
What about the rubber rings? Often this is an weak point, even with well known products like from Sigma (like the Cuberider II).
 

Skyraider59

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You are right, the rear light is at least as much important than the front light.
Unfortunately, this one has one common drawback: low to nearly no side visibility due to the low horizontal beam angle.
Especially in city traffic, this can be very important.

500lm are impressive. If it really are 500lm.
If CR123 is a good option if 18650 would be more common?
What about the rubber rings? Often this is an weak point, even with well known products like from Sigma (like the Cuberider II).

There is a small cut out on the side letting some light sideways but their light beam instead of being directed horizontally to the traffic behind like most lights, is directed towards the ground. Due to the light high output it's create a large red spot on the ground visible from all angles, on my bike it is also reflected on my black plastic mudguard giving the illusion of a secondary light, this is also visible sideways. As you can see from the photos the light is still visible as conventional lights but also has what I call a "GROUND HALO" and secondary effect.

Please note, this is my own interpretation of the design as the manufacturer does not explain the reasons behind this specific design! All I can say is: this work well.

Regarding the use of 18650 battery, this certainly would give longer run time but would also increase the physical size of the rear light.

Regarding the rubber rings, again this is not my preferred method of attachment on a rear light, I would have preferred a clamp to make it more secure, but again this work and the light is still there and it is very quick to remove or install!
The two rings supplied look good quality and are different to the oval type used on front lights, but I don't know how they will age!
It may be worth rigging a lanyard if you was worried!

I hope this help
 

swhs

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Looks high quality, but I'm wondering how annoying it is to ride behind (as a cyclist)... (because of the lens instead of a light distributing optic)

The lamp bounce effect can be seen in action from headlamps too as I noted on my site ( http://swhs.home.xs4all.nl/fiets/te...index_en.html#niet_conventionele_achterlampen ), but it's not very efficient. I wonder if a Lineo for example isn't at least as well visible as this lamp because it sends the light where it needs to go instead of relying partly on bounce (with absorbtion)

500 lm is impossible with 5hrs on a 3.7V 0,8Ah battery. 2.96Wh/5h = 0.592W. Not sure what the efficiency of red XML2s is, but I think 200 lm/W is about the maximum achieved for LEDs so that would mean 120 lm. It's probably less, optical losses ca. 15%, and lower efficiency, so 50 lm? Perhaps they mistakenly added a 0...
 

Skyraider59

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Looks high quality, but I'm wondering how annoying it is to ride behind (as a cyclist)... (because of the lens instead of a light distributing optic)

The lamp bounce effect can be seen in action from headlamps too as I noted on my site ( http://swhs.home.xs4all.nl/fiets/te...index_en.html#niet_conventionele_achterlampen ), but it's not very efficient. I wonder if a Lineo for example isn't at least as well visible as this lamp because it sends the light where it needs to go instead of relying partly on bounce (with absorbtion)

500 lm is impossible with 5hrs on a 3.7V 0,8Ah battery. 2.96Wh/5h = 0.592W. Not sure what the efficiency of red XML2s is, but I think 200 lm/W is about the maximum achieved for LEDs so that would mean 120 lm. It's probably less, optical losses ca. 15%, and lower efficiency, so 50 lm? Perhaps they mistakenly added a 0...

Regarding the LED as mentioned in my review, I do not believe they are XML on my sample but I think they are Cree XLamp XB-D 2.5x2.5mm Red color LEDs
This is what I have found on the net at http://www.forumled.com/led/archives/4713
XLamp XB-D color LEDs deliver up to 1416 mW for royal blue, 92 lumens for blue, 198 lumens for green, 210 lumens for red and 261 lumens for red-orange, all at 1A in the 2.45 mm x 2.45 mm footprint.
This is of course theoretical and not OF figures and unfortunately are the figures that most manufacturers like to give!
I have an home made integration sphere which I use for checking front lights with a Lux meter, but I have not used this for the rear light as I don't know how relevant a LUX reading of a red light would be! (Can you advise?)

962880d1423515334t-review-cb-seen-city-slicker-twin-led-500-lumen-rear-bike-light-img_0009.jpg


Thanks for your link about the various rear lights, fantastic study.

Regarding how annoying riding behind this light would be, I can not say as this is only use for cycling to work, all the club rides I do are MTB and we do not use rear lights.
 

swhs

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Regarding the LED as mentioned in my review, I do not believe they are XML on my sample but I think they are Cree XLamp XB-D 2.5x2.5mm Red color LEDs
This is what I have found on the net at http://www.forumled.com/led/archives/4713
XLamp XB-D color LEDs deliver up to 1416 mW for royal blue, 92 lumens for blue, 198 lumens for green, 210 lumens for red and 261 lumens for red-orange, all at 1A in the 2.45 mm x 2.45 mm footprint.
This is of course theoretical and not OF figures and unfortunately are the figures that most manufacturers like to give!
I have an home made integration sphere which I use for checking front lights with a Lux meter, but I have not used this for the rear light as I don't know how relevant a LUX reading of a red light would be! (Can you advise?)

Well, as there are of various LEDs themselves fairly accurate measurements (not by the manufacturer! For Cree esp. the values measured have deviated a lot! In a bad way, so less output than claimed), the easiest method is simply this: Take the measured values for bare LEDs, if needed do some interpolation from the datasheet at currents not measured, take off 15% optical losses, and that is about what comes out of the lamp...

The max. I read not long ago was about 200 lm/Watt for red LEDs, your figure is much lower (edited) see next posting.

The lux rating should work for red light too I think (depends on the lux meter), just try it and let us know the results...

Thanks for your link about the various rear lights, fantastic study.

Regarding how annoying riding behind this light would be, I can not say as this is only use for cycling to work, all the club rides I do are MTB and we do not use rear lights.

Well, I mean it this way: If you look at it from some distance, do you think "nice light" or do you think "fooking hell, that lamp is annoying!" ;-))

It's actually very hard to quantify, but I'm working on some sort of measure, theoretical for now, on how to deal with this. What is a problematic especially, is point sources. Wide beams from bigger lenses are also annoying but if wide/even enough, then at least there is not a huge brightness difference and that is a problem. For me the original Magicshine at 550 lumen caused being completely blinded, but not so for a Betty at 1850 lm because of the wider more even beam (not hotspot).

I'm working on this issue for my own 'standard' to counter the pathetic and 'to pay for' standards such as StVZO/TA, DIN, BS 6102-3 etc. Standards that are referenced in laws, become part of the law and should be therefore be free for all to examine! Otherwise government should not use such 'standards' by commercial bodies, but just make something themselves, i.e. order a standard and then make it freely available.
 
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swhs

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The max. I read not long ago was about 200 lm/Watt for red LEDs, and that's similar to your figure so if those are the LEDs used it would be about the max possible: 210 lm / W, so for 0.6W it would be 126 lm, take off 15% optical losses and you have 107 lm... Not bad.

Datasheet: Vf is around 2.7V for these LEDs at around 0.1A - 0.35A, and the 67 lm at 0.35 A means in this lamp you get about 67 * 0.6 * 0.85 = 35 lm... + a bit extra as the LEDs are driven even lower than 0.35A, but not much.
 
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