Seat stay rear lights

[quixoticgeek]

I'm in the market for some reliable, durable, rear lights to mount on my seat stays. Something with really good battery life (178+ hours on constant). Bonus if they meet German standard for lights.

Can anyone recommend something suitable? 

J

[dim]

I'm not sure if you will find a bike light that runs on batteries and which lasts that long (unless you get one that can work while it is being charged with a power bank (so you will need a saddle bag that will hold a powerbank) .... I have a Cygolite Hotshot .... super bright and you can dim it, and it works connected to a powerbank

Why do you only need to recharge every 178 hours? (Are you going camping or on Safari?)

[Kim]

The Secula is a good seatstay-mounted rear light, and there appears to be a battery version ("permanent" in B&M-speak).  I doubt you'll get more than about 24 hours from a pair of AAA cells, though.

AA-powered rear lights do somewhat better (though probably not 178 hours), but they tend to be rack-mounted.

So you're probably into the world of integrated Lithium-ion batteries and USB charging.  Most of those that I've come across seem optimised for brightness rather than runtime, though (presumably on the basis that they're targeted at commuters), so you may struggle to find one with a long runtime that doesn't flash. 

I'd generally solve this one with a dynamo light, but since you're not asking for that, I assume either the bike doesn't have one, or you want this as a redundant auxiliary.  However, some of the newer Reelights appear to have a constant mode, so maybe they'd be suitable?  https://www.reelight.com/collections/fork-seat-stay-mounting/products/city

[yorkie]

Like Kim, I would also solve this problem with a dynamo, but that wasn't the question!

I have a Lezyne Strip Drive 150 rear light, which mounts quite nicely on the seat stay, but only goes up to a maximum of 30.5 hours on flashing, 18 hours on the economy 3 lumen steady setting. The other problem with this light for your purpose is that it plugs into a standard USB socket and while it will happily run whilst charging, you would need to carry a USB extension cable to do so!
I also have a FibreFlare red light, but that doesn't even come close to meeting German standards!

[ijsbrand]

The Secula is a good seatstay-mounted rear light, and there appears to be a battery version ("permanent" in B&M-speak).  I doubt you'll get more than about 24 hours from a pair of AAA cells, though.

AA-powered rear lights do somewhat better (though probably not 178 hours), but they tend to be rack-mounted. [...]

There is indeed such a Secula. It is fairly energy efficient -- I easily can do a year with one pair of batteries -- but I doubt the hours ridden in the dark on that bike add up to more 30.

AA battery lights are said to last 80 hours max on one pair -- doubt they'll manage that in a cold winter.

[Brucey]

I would be amazed if you found such a thing (to meet German specs which have only recently acknowledged the existence of the battery light) and I would be even more amazed if it was both reliable and (if rechargeable) had a battery in it that retained its capacity for more than few charge cycles.

If you were to (say) assume 30mA as a target current (most use more than this) x 178 =  ~5300mAh.     IIRC you would need that current at a voltage of at least 1.7V or so.  This isn't beyond reasonable expectation but it is not something I have seen in a rear light that comes anywhere near meeting the other boundary conditions.

To put it into perspective, I would say that 178 hours comfortably exceeds the total life of a typical battery light, before it breaks in some interesting way or falls off the bike or something.

 IME battery rear lights -even quite expensive ones-  are pretty crappy things; most folk that use them and have any sense of self-preservation tend to carry at least two of them, so that they can be reasonably certain of there being at least one that is still working.

cheers

[grams]

Those cheapy pound shop 5 LED 2xAAA rear lights seem to have approximately infinite battery life. It's a shame the mounts are usually rubbish.

[quixoticgeek]

I'm not sure if you will find a bike light that runs on batteries and which lasts that long (unless you get one that can work while it is being charged with a power bank (so you will need a saddle bag that will hold a powerbank) .... I have a Cygolite Hotshot .... super bright and you can dim it, and it works connected to a powerbank

Why do you only need to recharge every 178 hours? (Are you going camping or on Safari?)

Not charge every 178 hours, last 178 hours. Why? Because that's how long the race is. If it lasts 178 hours I can set it going when the race starts and not have to worry about it for the rest of the race. I don't know what I will have available to me by way of access to power during the race, so don't want to rely on having to charge things.

Something that uses AAA or AA I can probably get spare batteries from a petrol station, if the spare set I carry aren't enough. But I'd like to not have to worry.

The Secula is a good seatstay-mounted rear light, and there appears to be a battery version ("permanent" in B&M-speak).  I doubt you'll get more than about 24 hours from a pair of AAA cells, though.

Peter White cycles suggests it lasts 20 hours on AAA batteries. I'm wondering if running it on non rechargable lithium batteries would substantially increase the life.

AA-powered rear lights do somewhat better (though probably not 178 hours), but they tend to be rack-mounted.

No rack on the bike so rack mount is no good.

So you're probably into the world of integrated Lithium-ion batteries and USB charging.  Most of those that I've come across seem optimised for brightness rather than runtime, though (presumably on the basis that they're targeted at commuters), so you may struggle to find one with a long runtime that doesn't flash. 

And struggle to find one that has a nice mount on the seat stay.

I'd generally solve this one with a dynamo light, but since you're not asking for that, I assume either the bike doesn't have one, or you want this as a redundant auxiliary.  However, some of the newer Reelights appear to have a constant mode, so maybe they'd be suitable?  https://www.reelight.com/collections/fork-seat-stay-mounting/products/city

Dynamo light is not an option for this situation, the dynamo output is already ear marked for other purposes. Not to mention that even if I had 1 rear dynamo light, I would still need another as a second light.

That reelight looks interesting. It's €40, so not cheap, but if it's reliable and works off free energy, it could be worth considering.

Like Kim, I would also solve this problem with a dynamo, but that wasn't the question!

Not an option.

I have a Lezyne Strip Drive 150 rear light, which mounts quite nicely on the seat stay, but only goes up to a maximum of 30.5 hours on flashing, 18 hours on the economy 3 lumen steady setting. The other problem with this light for your purpose is that it plugs into a standard USB socket and while it will happily run whilst charging, you would need to carry a USB extension cable to do so!
I also have a FibreFlare red light, but that doesn't even come close to meeting German standards!

Yeah, I am uninspired by the USB chargable options I've found so far.

I would be amazed if you found such a thing (to meet German specs which have only recently acknowledged the existence of the battery light) and I would be even more amazed if it was both reliable and (if rechargeable) had a battery in it that retained its capacity for more than few charge cycles.

While not optimal, if there was something that wasn't too expensive, single use and had a 200hr life (So I can test it a couple of times first), then that would be an acceptable solution.

If you were to (say) assume 30mA as a target current (most use more than this) x 178 =  ~5300mAh.     IIRC you would need that current at a voltage of at least 1.7V or so.  This isn't beyond reasonable expectation but it is not something I have seen in a rear light that comes anywhere near meeting the other boundary conditions.

I hadn't thought to do the maths on that. 5300mAh is not a small amount of energy. Tho I wonder if there are acceptable led's that draw less than 30mA. I know in the past I've used 2mA led's that were not fun to look at...

To put it into perspective, I would say that 178 hours comfortably exceeds the total life of a typical battery light, before it breaks in some interesting way or falls off the bike or something.

Yes, but it's actually 1 week and 10 hours of constant use. I appreciate that for many if their light lasted 178 hours turned on, it would be 1 hour each day for 178 days of cycling, but the light would be fitted for just shy of 6 months (or 1 London Winter), which is closer to 4272 hours. It's all about the Duty cycle vs the usable life.

 IME battery rear lights -even quite expensive ones-  are pretty crappy things; most folk that use them and have any sense of self-preservation tend to carry at least two of them, so that they can be reasonably certain of there being at least one that is still working.

Yes, hence my use of the plural in the subject line. I have 2 seat stays, I'd like one light on each stay. I also have a TL-LD570-R fitted to the seat post, which turns off during day light (unless you get mud on the sensor), and also doubles as a reflector. I need to have at least 2 functioning steady independent legal rear lights.

J

[fuaran]

Hope District Plus claims 200 hours battery life on low power. It uses a separate battery pack, so there is an option for a higher capacity. Or you could get a splitter cable to connect 2 lights to 1 battery.
Not sure how easy it would be to mount on the seat stays.

[quixoticgeek]

Hope District Plus claims 200 hours battery life on low power. It uses a separate battery pack, so there is an option for a higher capacity. Or you could get a splitter cable to connect 2 lights to 1 battery.
Not sure how easy it would be to mount on the seat stays.

Doesn't mount on the seat stays, would have to find a home for the battery pack, and if it goes flat becomes a dead weight unless I carry the charger. So not an optimal solution

J

[Samuel D]

You’ll probably have to make something if you don’t want to replace batteries along the way. These current draws, albeit mostly for dynamo lamps, might inform your choice of lamp to start with.

[andrew_s]

As an alternative, how about a Magnic light, or a pair of them?

They are effectively dynamo lights, with each light having its own mini-dynamo, spun by the close proximity of a moving wheel rim, and which powers a pair of LEDs to the tune of 1.5W or thereabouts.
Because they have to mount close to the rim, they are really only suitable for bikes unencumbered by a rear rack, and fit close to where rim brake pads would be (or are).
They also won't run on carbon rims, unless there's an aluminium brake track of a decent thickness.

Not STvZO, but that doesn't matter unless you live in Germany.

[Brucey]

a lot of battery rear lights and dynamo rear lights draw around 100mA. However in the case of battery lights what happens is that the current draw declines as the batteries weaken. The light stays on (dimly) and may continue for a great length of time depending on the battery chemistry.

  Boring old zinc-carbon batteries can have a very long 'tail' to their discharge curve which means that you get fair warning of many hours before the lights clap out on you. They also 'recover' so that if they are asked to run for an hour a day, they might do it for a long time.  With other battery chemistries, maybe not so much warning, not so long a 'tail'.

I chose 30mA as a target current because there are a few lights that draw about that amount and having used some they are bright enough.

BTW since the voltage drop is low enough in a red LED, you can arrange your (custom) dynamo lights to be configured in various ways; for example a standard 30mA rear can be in parallel with another set that comprises two 30mA lights in series. Total current draw is 60mA which is still less than most standard rear dynamo lights.

Maybe there is a way of using rechargeable batteries (that, say, take the other 40mA in charge current even when the lights are on) to give you reliable lighting.

cheers

[andyoxon]

Smart Lunar R1 lights (2xAAA) mount on seat stays (I have two arranged vertically), and possess a 'group rider' 2xLED fixed, low power mode quoted at 100hrs run time. Two units may give ~180hrs+.  These two LEDs are very directional, but could be diffused to give a decent 'glow' - which is what I do for the 1W output (using NiMH) on one light, which produces a very decent glow... 

[JamesBradbury]

Smart Lunar R1 lights (2xAAA) mount on seat stays (I have two arranged vertically), and possess a 'group rider' 2xLED fixed, low power mode quoted at 100hrs run time.

I was going to suggest this as a simple, low cost solution.

As long as you can mount them high enough on the seat stays to be legal, I forget how high that is. I also have some reservations about single seat stay lights being obscured by the rear wheel from certain angles, but if you're already running smothering on the seatpost maybe that's OK?

Sent from my SAMSUNG-SM-G891A using Tapatalk

[quixoticgeek]

I was going to suggest this as a simple, low cost solution.

As long as you can mount them high enough on the seat stays to be legal, I forget how high that is. I also have some reservations about single seat stay lights being obscured by the rear wheel from certain angles, but if you're already running smothering on the seatpost maybe that's OK?

IIRC the rear light needs to be between 350mm and 1500mm off the ground. On a 700C bike, I'd suggest it would be a struggle to mount a light to the seat stay below 350mm from the ground... This however is the British standard (BS6102/3). My usecase for this particular thread is the Netherlands, where the requirement is: a light, it should be red, it should point backwards. My reason for specifying StVZO compliance in my original request, is this tends to avoid the cheap crap that fails too early, and tends to not be worth using. At a guess, >90% of lights on the market are utter crap. By looking at stuff that complies with a known standard, you tend to exclude that >90%.

Current options for serious consideration:

- B&M SECULA permanent (20 hrs on constant) - €16.22
- Smart Lunar R1 (200hrs on low) - £12.99
- Cat eye Omni 3 (100hrs on constant) - €9.49
- Reelight City Supreme (Unlimited) - €46 front/rear set.

I want to have 2 of what ever light I choose, one on each seat stay. This means that if one fails, I can swap which side the active light is on (For Dutch riding, a light on the left side is preferred).

Of these lights, only the B&M meets the StVZO requirements.

Need to have a think. I may end up buying several to evaluate them.

J

[dim]

I'd still opt for a cygolite hotshot and a powerbank, and run the light directly off the powerbank

you can get lipstick sized powerbanks or larger (I have a RAV that is 26 800 mAh) that will charge the cygolite for several days

you can get an Apidura top tube bag to store the powerbank and you can mount it to the seatstay:



or even better, you could store the powerbank in a saddle bag?

[jsabine]

You could just go cheap with a couple of Planet X Phaart Bleeps.

Bright and reliable, IME, and while they don't quote a battery life I don't recall changing the (alkaline, cheap) AAs during the Wild Atlantic Way audax in 2016, which for me was about 190 hours. Granted, I was running them at night rather than constantly, but the switch was easy enough to use that it wasn't mentally taxing even towards the end, and I can turn them on from the saddle without too many contortions.

I've been using them for several years, including a few long audaxes and some lousy weather, and so far I've had no lights and one bracket fail. In normal use, the battery life is long enough that I just don't track it.

[Zed43]

If this is about Race around the Netherlands, consider a blinking rear light if you want maximum battery life. Yes, it's illegal according to the letter of the law, but no Dutch policeman will fine you for using one. Also, personally I would switch it off during the daylight, I don't see the point of using a bicycle light during the day unless it is either very very bright or the weather is really dark.

I own a B&M SECULA and the fiddly on/off switch annoys me no end...

[quixoticgeek]

If this is about Race around the Netherlands, consider a blinking rear light if you want maximum battery life. Yes, it's illegal according to the letter of the law, but no Dutch policeman will fine you for using one. Also, personally I would switch it off during the daylight, I don't see the point of using a bicycle light during the day unless it is either very very bright or the weather is really dark.

I own a B&M SECULA and the fiddly on/off switch annoys me no end...

Was the 178 hours the hint?

Are you racing it too?

Yes, turning the light on/off is easy enough, But in twilight I don't want to find that the one point where I didn't think it was dark enough for a light to be on, is actually the point race control think it should be on and get a disqual. If I can turn things on on the first day and not have to remember to turn things on again, it means that if I forget to turn it off, I don't then have to divert to a petrol station to find batteries... it's about minimizing the work load for the brain. Yes turning a light on/off is relatively easy, but if I don't have to do it, then it's better.

As for flashing, yes no police officer is going go tell you off for it, but personally I find it a right sod to follow blinky lights, so I try not to inflict it on others.

J

[Zed43]

Was the 178 hours the hint?
Are you racing it too?

By coincidence I read a blurb on fiets.nl about RatN just moments before No, I will be riding the Bryan Chapman on the 19th, followed by two more weeks of riding in the South-West and another brevet; 1600km just prior to that doesn't seem to be a good idea...

As for flashing, yes no police officer is going go tell you off for it, but personally I find it a right sod to follow blinky lights, so I try not to inflict it on others.

Agreed, I too detest riding close behind a blinky for long periods. But RatN rules say "No Drafting at any time.", so the only people who you'll annoy with your blinky is either commuters (who, very likely, will have a blinky as well) or a fellow racer in the far distance. Your attitude is commendable, I would have had less compassion  (I do run full mudguards with flaps out of consideration for fellow randonneurs though)

[jsabine]

Personally, I reckon the cognitive load of 'it's going to be dark soon, better reach back and switch on my light' is less than 'that light's gone a bit dim, best change the batteries' - it's also less faff, given you're probably not going to get 180 hours runtime.

(I'd also be surprised if the organisers were aggressively looking for reasons to DQ - words of advice about lighting in twilight is a reasonable first step if it's a grey area.)

[quixoticgeek]

Was the 178 hours the hint?
Are you racing it too?

By coincidence I read a blurb on fiets.nl about RatN just moments before No, I will be riding the Bryan Chapman on the 19th, followed by two more weeks of riding in the South-West and another brevet; 1600km just prior to that doesn't seem to be a good idea...

Ah. I started the application process for the TCR. I then chickened out. Someone on twitter mentioned the RatN, and it seemed like a much more sensible introduction to the madness, and given I work in Amsterdam, it seemed very accessible.

As for flashing, yes no police officer is going go tell you off for it, but personally I find it a right sod to follow blinky lights, so I try not to inflict it on others.

Agreed, I too detest riding close behind a blinky for long periods. But RatN rules say "No Drafting at any time.", so the only people who you'll annoy with your blinky is either commuters (who, very likely, will have a blinky as well) or a fellow racer in the far distance. Your attitude is commendable, I would have had less compassion  (I do run full mudguards with flaps out of consideration for fellow randonneurs though)

I actually had someone take my blinky light off my pack and hand it to me as they passed because it was annoying them (this was when I was new to commuting in Amsterdam).

I'm new to this no drafting racing stuff. I'm fully expecting to be Lantern Rouge, but I do wonder how annoying it would be for a fellow competitor who has to catch me, and then pass me, without drafting. I haven't put any thought into the reverse, I don't expect to be overtaking anyone...

J

[quixoticgeek]

Personally, I reckon the cognitive load of 'it's going to be dark soon, better reach back and switch on my light' is less than 'that light's gone a bit dim, best change the batteries' - it's also less faff, given you're probably not going to get 180 hours runtime.

(I'd also be surprised if the organisers were aggressively looking for reasons to DQ - words of advice about lighting in twilight is a reasonable first step if it's a grey area.)

It's my first race of this kind, and I'm paranoid.

J

[JohnL]

Sorry, this not switching off thing is just daft. You’re going to sleep or eat at some point aren’t you? If so, some kind person will switch your light off. If you are not planning on thinking about it you’ll ride off with no light.

Get one with a sensor if you’re that worried about forgetting. Personally I’d use a dynamo. I don’t think the current to a rear light will make much difference to your charging kit. Better still use an Etrex which doesn’t need charging and keep your phone on airplane mode with a battery pack to top it up. All the juggling of charging off the dynamo wil use a lot more brain power than remembering to switch a light on.

Keep it simple.

John