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Are USB-rechargable lights any use ?

  • 26-12-2021 7:30pm
    Registered Users Posts: 323 ✭✭


    I bought a relatively expensive light (see attached photo) which has turned out to be a piece of crap. It has two problems which combined make it not just crap but dangerous:

    1. When the batteries drain the brightness goes from 100% to 0% instantaneously. Every other LED light I've had over the last 20 years or so degrades gracefully with the brightness decreasing gradually as the battery gets low so you have plenty of warning that the batteries need recharging before you are left, literally, in the dark.
    2. It has a 'low battery indicator' feature which the instructions say should light when the battery has dipped below 20% capacity. This feature does not work. The capacity is ~6hours (vs claimed capacity of ~7hours) but the 'low battery indicator' lights after about 15minutes use, or in other words its not a low battery indicator at all.

    1 & 2 combined mean that unless you charge it every day (which would be a pain in the ass) you basically have no idea when it is going to suddenly go completely dark.

    I concluded that its basically unusable and I'll just have to buy a new one and avoid the Inifini brand. Looking at new ones though I did start wondering, this is the first one i ever had that has a built-in, USB-rechargable battery (all my previous ones were AA or AAA powered). I'm noticing more an more of the ones on sale now are USB-charged and the battery capacities seem quite low (eg 220mAh vs ~2000mAh for 2 AAA batteries). I'm wondering if this sudden 100% brightness to 0% brightness transition might be a property of low battery capacity combined with high brightness LEDs? ie I'm wondering if I might find the same problem with any brand which has bright LEDs and a builtin USB chargable battery. Does anyone know if this is the case, or can you get USB ones where the brightness degrades gracefully as the battery drains ? I notice that only some of them (like my current one) list 'low battery indicator' as a feature, might this be a red flag to warn that it has this undesireable sudden 100%->0% behaviour ? None of my previous lights ever had a 'low battery indicator and I can't see why you would need one if they dim gradually with decreasing charge.

    So, does anyone know for sure, do I need to avoid USB-chargable lights alltogether, or just specific brands, or just any light which l list a 'low battery indicator' feature ?





  • Registered Users Posts: 24,888 ✭✭✭✭Wishbone Ash

    Why is charging the light daily a "pain in the ass". Don't your charge your phone daily?

  • Registered Users Posts: 22,466 ✭✭✭✭ted1

    Because it is.

    OP their is another light thread where I listed a link to a light with a runtime of Many hours

    Post edited by ted1 on

  • Registered Users Posts: 323 ✭✭Usjes

    Well for one its 14x more complicated that charging a light once every two weeks, but more importantly the instructions specify that the battery is good for 500 charging cycles, So if I charge it every day that means the battery is dead in under two years vs. a 10 year lifespan if I charge it once every two weeks. My back light is AAA powered and has been working fine for 8 years. Moreover the questions I asked were quite specific; is this behaviour specific to USB-chargeable lights if you don't know the answer then you're just cluttering the thread with noise. If you want the an answer to your inane question of 'why is it a problem to do soemthing unnecessarily every day' then maybe you could start a separate thread on that subject, maybe on the 'After hours' forum.

  • Registered Users Posts: 764 ✭✭✭gn3dr

    I have a few USB rechargeable lights and they are OK - the low battery indicator works OK. I'm not an expert on lights but I've never heard of that brand - so expensive or not I'd stick with brand names (Cateye, Garmin, Lezyne etc...) . If you want a small "be seen" front light then the Bontrager ION RT 200 automatically switches to a lower power output when the battery reaches a certain %.

  • Registered Users Posts: 1,233 ✭✭✭Garzard

    No, the problem of the LED just going out is not specific to USB powered lights, but may be more prevalent on newer lights with more (and/or cheaper) electronic.

    When the voltage drops, and the LED is pulling the same power, the current will spike. It tends to be higher current that burns out electronics. So the manufacturers put in self protection electronics which just switch off abruptly if the voltage drops too low, rather than build the light to handle the higher current. They could include a constant current controller, or only allow the light to flash at low batter voltages, or use PWM to give a dimming effect, but all of these solutions cost more. My Lezyne light only allows flashing or low brightness if the batter is low. It also have 4 tiny LED which go from green to orange to red as the battery drains.

    That said, I think you just have a dodgy light - the low battery warning should not be coming on after 15 minutes.

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  • Registered Users Posts: 323 ✭✭Usjes

    Funny you should list Cateye as a good brand. I used to buy only cateye but then I bought two of them that failed in the rain. One for myself (shown below). The rain affected the circuitry such that rather than having 3 distinct flashing patterns it now just flashes erratically when I turn it on, its still usable but clearly the rain messed with the internals.You can even see the sellotape I added round the seam to try to prevent further rain ingress. Around the same time I bought another expensive cateye for my sister and it died alltogether the first time being out in the rain, like the battery shorted and fried it altogether. So after that I decided the quality of cateye had gone to crap and that I would never buy one again.

  • Registered Users Posts: 323 ✭✭Usjes

    "When the voltage drops and the LED is pulling the same power." Well it sounds like that is the problem I guess this must be specific to these more powerful LEDs in newer lights. Because I = V/R so I would expect as V drops R remains the same and => I would drop also and the LEDs would flash more dimly which is exactly what happens with my back light (pictured below, €1.50 in Dealz and still working fine after 8years) and any previous lights I've had. So it sounds like I basically need to avoid USB-rechargeable lights. If all newer lights will potentially exhibit this instant cutoff and 'low battery indicators' can not be relied upon then the best strategy is to buy a light with as long a battery as possible so that I'll get caught out less frequently. So AAA powered lights are the best bet, they last literally for months on alkeline batteries. You'd think there would be some sort of regulations against these lights that fail instantly rather than dimming gradually; they're dangerous.

  • Registered Users Posts: 4,192 ✭✭✭MojoMaker

    That behaviour has never happened on any rechargeable lights I have ever owned. You either have a faulty light or a crap manufacturer - or quite possibly both.

  • Registered Users Posts: 323 ✭✭Usjes

    So you are saying that on all your lights they dim gradually as the battery drains ? When did you last buy a light. I had never seen this behaviour before either until I bought this new light. Also Garzard above gives a detailed explanation as to why this is happenning so I'm clearly not alone, moreover lots of the new lights I see do list 'low battery indicator' as a feature which makes no sense unless the lights suddenly jump from full beam to nothing. So perhaps it is just a new 'feature' you have to look forward to when you next buy a new light.

  • Registered Users Posts: 2,041 ✭✭✭UrbanFret

    The nature of modern rechargeable batteries be it drills, impact drivers etc is you have full power until you have no power. These bike lights are most likely the same.

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  • Registered Users Posts: 82 ✭✭MyDarkArts

    I found that Infini brand poor. They were expensive enough for what they were. The USB charging port was dodgy for a bit until it stopped charging altogether and it had to be binned. Got a Lifeline replacement that is a better light and cheaper too.

  • Registered Users Posts: 4,192 ✭✭✭MojoMaker

    The lights I have at the moment deplete progressively, going from a visual blue indicator (> 75%) to a yellow (25-75%) and finally a red (< 25%). When showing a red light the flash modes are significantly reduced from 7 to a single operational (eco) mode. When red I have about 1 hour in eco mode before the light will give up.

    I only use burst mode in urban riding so the light is never on continuously. In the flash mode I prefer - which is a quasi-strobe mode - I get about 6 hours use before hitting red. That's 3 days commuting 45k / 2 hours per day. Re-charging is 2 hours on main adaptor or 3 hours from usb power source so you're never really stuck.

    I have two sets of them so even if I forget to charge I always have a fresh set handy. If I let both run down - well then that's on me.

    They are really small and light and use durable rubber clamps so they are on & off the bike in seconds and fit all bars and seat posts - no brackets or mounts.

  • Registered Users Posts: 11,676 ✭✭✭✭tomasrojo

    Most of my lights are AA- or AAA-based, and most of those do a visual warning when battery store is getting low.

    I have a German lighting-standard Cateye headlight (GVolt 20), which I like a lot. You need mudguards and to mount it the right way, as it does have a discontinuity in the plastic shell where the mounting block is. But this isn't a problem for me.

    You only get about ten minutes' more light when the red warning light comes on.

    AA- and AAA-based lights are good in the sense that you can have recharged lights ready to go at all times, and the light lasts as long as the LED and the body remain functional.

  • Registered Users Posts: 5,870 ✭✭✭DaveyDave

    Similar to MojoMaker, my lights have several battery indicator lights (green, yellow, red, red flashing) and on red flashing only a solid but very dim light is on which lasts about an hour I believe so I'm never stuck.

    I charge it after 2 days as I won't get a full 3rd day so I'm never really caught without it. Can't say I've had any quality issues from a series of CatEye AA/AAA lights or my current front and rear Lezyne rechargable lights.

  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 46,928 CMod ✭✭✭✭magicbastarder

    AA- and AAA-based lights are good in the sense that you can have recharged lights ready to go at all times, and the light lasts as long as the LED and the body remain functional.

    i'll echo this - i had one of the cheap but powerful aldi light (or lidl? - the lozenge shaped one) but the battery failed after about 14 months.

    with my AAA powered lights, i have two for redundancy and when i was commuting i was also able to carry spare batteries in case of an issue. you can't do that with lights which don't have removable batteries.

  • Moderators, Arts Moderators Posts: 10,509 Mod ✭✭✭✭5uspect

    I’m lucky enough that my ebike has integrated lights. I’ve also got see.sense lights which have great battery life.

    I used to have a windup light years ago but it flew off when I hit a bump once and got crushed by a truck.

  • Registered Users Posts: 764 ✭✭✭gn3dr

    Simple solution to those of you that distrust USB charged lights - carry a power bank around with you as a backup. Some of these can be tiny.

    I'm slightly bemused at the fear of USB charged stuff in a world where everyone has a phone that is USB charged.

  • Registered Users Posts: 1,597 ✭✭✭tdf7187

    I'm old school on this, prefer the traditional battery operated lights. Yes it's a pain in the arse having to replace batteries every so often, but it's equally if not more of one having to plug in the yoke into your PC or wall socket every few days (if you're a daily cyclist, less often if only occasional one).

  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 46,928 CMod ✭✭✭✭magicbastarder

    'fear' is a funny word to use. if people were worried about their commutes being made more dangerous by their phones running out of charge, i'm sure they'd be addressing that issue too?

    a powerbank would be handy, if you can easily power the light off it while still cycling?

    removable batteries can address the issue of running out while in use, and also of having several full charges available almost instantly; and of dealing with battery failure (as opposed to battery exhaustion). i've been there, had rechargeable lights fail on me but i've not been let down by lights with replaceable batteries in the same way.

  • Registered Users Posts: 617 ✭✭✭Minier81

    I use a rechargeable USB pair from decathlon that cost about 30€ and find them good. An indicator turn red when they are running low, like have 2 have charge left. They seem to last about 20 hours in flashing mode. Delighted with them.

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  • Registered Users Posts: 11,676 ✭✭✭✭tomasrojo

    Yeah, I have a power bank, and it's very handy, but if lights are discharged, I can't cycle while they're charging. If I mess up and go out with AAA/AA lights that are just about exhausted, I can make them good for hours in a minute. This is actually easier than it used to be, now spare AAA/AA rechargeables will keep charge for about a year.

  • Registered Users Posts: 24,888 ✭✭✭✭Wishbone Ash

    If people are unwilling to recharge their lights regularly, they are hardly going to feel any different about ensuring that the power bank is adequately charged.

  • Registered Users Posts: 33,547 ✭✭✭✭o1s1n
    Master of the Universe

    I just have two on the front. I'll only use one and if it dies, I've the second one as a backup. Can then get home and get the first one charged back up again.

  • Registered Users Posts: 16,414 ✭✭✭✭dahat

    See sense front light for daytime

    Two Aldi Cree (?) front lights for night

    One Cat eye rear light

    All are usb charge and given a full charge after each use to avoid the dreaded dead battery. The key for me is to know how long each will last before heading out on any spin.

  • Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 46,928 CMod ✭✭✭✭magicbastarder

    i remember reading that li-ion batteries are best stored at between 20% and 80% charge, they shouldn't be left for long completely full or empty, it can shorten their lifespan. at least that was the advice when i was looking up battery care after my wife got her e-bike (a battery which costs €500 to replace makes you a little more aware of getting the best from it)

  • Registered Users Posts: 36,142 ✭✭✭✭ED E

    I bought a relatively expensive light 

    Sorry but no you didn't. €30 isnt a high end light.

     I'm noticing more an more of the ones on sale now are USB-charged and the battery capacities seem quite low (eg 220mAh vs ~2000mAh for 2 AAA batteries)

    One is not like the other.

    220Mah @ 4.2v = 0.924Wh

    1000Mah @ 1.5v = 1.5Wh

    So yes in theory the AAs have more capacity but any light using 220Mah LiPo cell is going for size/weight not endurance.

    Decent lithium based lights are grand. You should get one that goes amber at <40% and flashes at <20%. Then you have plenty of warning. Honestly you just bought a dud. Its likely the thresholding in the chip was never set/set wrong so it's detecting say 4.1v as near empty making the indicator useless.

  • Registered Users Posts: 11,676 ✭✭✭✭tomasrojo

    Definitely can't beat Li-ion for tiny bright lights.

  • Registered Users Posts: 22,076 ✭✭✭✭breezy1985

    Any I have had switch to dim or go auto flash when low. They all had some form of charge indicator too.

    I do miss the battery powered ones but good ones are very hard to find now

  • Registered Users Posts: 11,676 ✭✭✭✭tomasrojo

    Think €30 should get you an acceptable headlight for commuting with occasional unlit trips. Obviously, there are much more powerful and expensive lights for offroad or rural night cycling.

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  • Registered Users Posts: 3,817 ✭✭✭TaurenDruid

    A detachable USB-rechargeable LED front light came with my ebike (and a built-in rear light). The battery lasted quite a while on the front light as mounted under the front carrier, the vibration made it switch off after every bump! Moved it to the handlebars and it's been fine - green LED for when it has sufficient charge, switches to red LED when it's low on power, output isn't effected. Sounds like the one you have is defective. I picked up a spare front light from the Dublin Cycling Campaign one evening there where they were giving them out, so I've backup in case I do run out of juice.