"Zog The Undeniable" <hrothga...@yahoo.com> wrote in message
> LEDs are not good when run on rechargeable batteries. They are very > voltage-dependent. I have done the measuring with a light meter and the > output on NiMH is roughly halved compared with fresh alkaline cells. If > you use LEDs, I strongly recommend lithium AA cells, as they are a full > 1.5V with a much flatter discharge curve (and, as a bonus, are spookily > lightweight).
You need to use a constant current/regulated supply.
Zog The Undeniable wrote: > LEDs are not good when run on rechargeable batteries.
Here we go again.
I use LED lights with rechargeables, and in contrast to when I used alkalines, they're always nice and bright now.
> They are very voltage-dependent.
Which is why they're better with NiMH or NiCad batteries than Alkalines -- unless you fit new batteries every half hour.
> I have done the measuring with a light meter and > the output on NiMH is roughly halved compared with fresh alkaline > cells.
There's not that much difference in initial brightness with the Smart and Eurolight LEDs I use, and alkaline cells in them don't stay above 1.2V for long anyway. The /average/ brightness is higher with rechargeables when charged frequently.
Modern LED lights are so bright that it doesn't really matter about not having the most out of them anyway -- which I think you could only have with lithiums.....
> If you use LEDs, I strongly recommend lithium AA cells, as > they are a full 1.5V with a much flatter discharge curve (and, as a bonus, > are > spookily lightweight).
They are much more expensive than using rechargeables and you need to carry spares once uncertain how much juice is left, negating the weight saving. More expensive than bulk-bought alkalines as well in terms of cost per hour.
> When I wrote the above I was thinking more about MR11-based systems and > forgetting about the large 3W halogen light I used to use with a dynamo. > That was quite useful on unlit roads. So it depends on the type and size > of the lamp and bulb as well as the wattage (and the amount of > over-volting).
Yes - proper bike lights have a better beam pattern. I use 3w halogen on unlit roads.
Anthony Jones wrote: > I haven't seen a EL-530, but I'd /guess/ that like most Cateye lights it's > unregulated (meaning the light output quickly decreases as the batteries > run out), and that it probably doesn't have quite as good a beam pattern on > the road.
> Anthony
I have an EL500 and I pretty sure it is regulated. I have no reason to think that the EL530 wouldn't be as well.
IIRC, the EL500 has a switch that electronically 'latches', i.e. contact of the switch toggles the light on or off (correct me if I'm wrong on that). I suspect that is what the circuit is for. I cannot see a transistor large enough for the circuit to be a linear regulator, nor an inductor as I would expect to see in a switching regulator.
> IIRC, the EL500 has a switch that electronically 'latches', i.e. contact of > the switch toggles the light on or off (correct me if I'm wrong on that). I > suspect that is what the circuit is for. I cannot see a transistor large > enough for the circuit to be a linear regulator, nor an inductor as I would > expect to see in a switching regulator.
> Anthony
The black blob with U1 next to it is a 16 pin integrated circuit of some kind. The device labelled Q1 is a transistor, and some surface mount transistors like that, are easily capable of switching 0.25A, in fact Philips do a SOT-23 transistor capable of handling 2A. So it is quite reasonable to expect that somewhere in there is a power regulator. Otherwise it seems an awful lot of circuit for a magnetic switch.
Stephen wrote: > The black blob with U1 next to it is a 16 pin integrated circuit of > some kind. > The device labelled Q1 is a transistor, and some surface mount > transistors like that, are easily capable of switching 0.25A, in fact > Philips do a SOT-23 transistor capable of handling 2A.
I'm not an electrical engineer by any means, so I may be getting out of my depth here, but assuming a linear regulator surely power dissipation is going to be the issue, not current? I don't think a switching regulator without an inductor would work (since fully charged NiMH batteries would provide more than the maximum rated current through the LED). Perhaps Cateye uses the same IC in different configurations for various lights (flashing etc.), explaining the complexity?
Anyway, none of this explains the current readings that I linked to previously, nor the existence of the EL500G. If you're willing to take some current vs. voltage readings, I could be convinced (although then I'd be tempted to think that you have a EL500G rather than an EL500).
On Thu, 02 Nov 2006, Anthony Jones <n...@antjones.fastmail.fm> wrote:
> I'm not an electrical engineer by any means, so I may be getting out of my > depth here, but assuming a linear regulator surely power dissipation is > going to be the issue, not current? I don't think a switching regulator > without an inductor would work (since fully charged NiMH batteries would > provide more than the maximum rated current through the LED). Perhaps > Cateye uses the same IC in different configurations for various lights > (flashing etc.), explaining the complexity?
You can regulate LEDs with PWM and don't need an inductor. At least one of teh bike light manufacturers appears to do so, as the link you (I think) previously provided explains.
Anthony Jones wrote: > Perhaps > Cateye uses the same IC in different configurations for various lights > (flashing etc.), explaining the complexity?
> Anyway, none of this explains the current readings that I linked to > previously, nor the existence of the EL500G. If you're willing to take some > current vs. voltage readings, I could be convinced (although then I'd be > tempted to think that you have a EL500G rather than an EL500).
> Anthony
The EL500 is either on or off, there is no flashing or anything like that. If I have time in the next few days I'll do the measurements.
Ian Smith wrote: > You can regulate LEDs with PWM and don't need an inductor. At least > one of teh bike light manufacturers appears to do so, as the link you > (I think) previously provided explains.
Indeed, I hadn't noticed that. The light in question /is/ described as being an 'unusual regulator design' though.
Anyway, hopefully Stephen will be able to take some measurements. I'll be happy to be prooven wrong if it makes my future light purchases easier!
Anthony Jones wrote: > [Cateye HL-EL500G] > Anyway, hopefully Stephen will be able to take some measurements. I'll > be happy to be prooven wrong if it makes my future light purchases > easier!
Andreas Oehler published the following figures on the bikecurrent mailing list:
################################################################## Date: Tue, 19 Oct 2004 22:39:58 +0200 To: bikecurr...@topica.com Subject: Re: [BC] CatEye HL-EL500G: regulated?
I haven't found a way to get to the PCB(s) without damaging the lamp permanently - so I just had the possibility to do some measurements at the battery contacts. The "meter" I have here in the moment is less accurate than what I am used to - so don't over-interpret the numbers:
Cateye EL-500G
voltage | current | low batt indicator ---------+-----------+-------------------- 4.00 V | 440 mA | on (light darker) 4.25 V | 520 mA | on 4.60 V | 500 mA | on 4.80 V | 460 mA | off 6.00 V | 400 mA | off 6.50 V | 360 mA | off
This means, the lamp is regulated: It consumes a constant 2.2-2.4 Watt when battery voltage is higher than 4.25 Volt. It can be used either with alkaline or NiMH cells.
As far as I can tell the regulating circuit is inside the light head. As this part is ultrasonic welded like Andreas I did not manage to open it. The figures show that the light works well with rechargables. It does not make the best use of them as light output drops when the cells reach 1.0 V each. IME it works for about 4 h under real world conditions (well used cells, temperatures typical for night time rides). Also the low battery warning lights up quite early. Cateye claims 6 h for the G-version. I never reached this but it is well less exegarated than their run time claims for the international version or the infamous 100 h for the HL-EL300.
Günther Schwarz wrote: > Anthony Jones wrote: >> [Cateye HL-EL500G]
Unfortunately we were talking about the EL500, not the EL500G. I'd previously mentioned in this thread that the EL500G was regulated, but also that I'd never seen them for sale here.
The Cateye website claims a runtime of 8-10 hours for the EL500G, but 30 hours for the EL500:
Anthony Jones wrote: > Günther Schwarz wrote: >> Anthony Jones wrote: >>> [Cateye HL-EL500G]
> Unfortunately we were talking about the EL500, not the EL500G.
It might be of interest to complement Andreas' figures with a voltage vs. current curve of the international version.
> I'd > previously mentioned in this thread that the EL500G was regulated, but > also that I'd never seen them for sale here.
I assume that you are in Britain, so you might profit from the common market. It works quite well the other way: from time to time a will get a hard to find part from the UK.
> The Cateye website claims a runtime of 8-10 hours for the EL500G, but > 30 hours for the EL500:
In message <454bb682$0$8742$ed261...@ptn-nntp-reader02.plus.net>, Anthony Jones <n...@antjones.fastmail.fm> writes
>Günther Schwarz wrote: >> Anthony Jones wrote: >>> [Cateye HL-EL500G]
I've just bought an EL530 and will keep a runtime record with the provided batteries. Amazingly bright compared to my 1W Smart but am disappointed with the beam pattern which very pencil-like. -- Chris
Would it be feasible to buy an MR11/MR16 halogen setup and then to replace the bulbs with LED MR11/MR16 to get increased running times with reasonable brightness? I assume that the single LED MR bulbs would be more suitable than the cluster ones (and I haven't seen any single LED MR11s anywhere as yet).
Otherwise, I'm also considering the EL530 for commuting -- roads both lit and unlit, and off-road lit and unlit (but on a good surface).
bcc97 wrote: > Would it be feasible to buy an MR11/MR16 halogen setup and then to > replace the bulbs with LED MR11/MR16 to get increased running times > with reasonable brightness?
As well as the brightness, you should check whether the beam angle, pattern and colour will be reasonable.
I bet the beam is rubbish compared to a 5W halogen MR11's.
bcc97 wrote: > Would it be feasible to buy an MR11/MR16 halogen setup and then to > replace the bulbs with LED MR11/MR16
Probably, although I believe the LED versions are sometimes slightly different shape, so they may not always fit.
> to get increased running times > with reasonable brightness?
You will sacrifice brightness for increased run times, and with the reduced brightness I suspect you'll struggle to find a 'bulb' with a tight enough beam to be much use for seeing on unlit roads. Personally, I wouldn't bother.
> I assume that the single LED MR bulbs > would be more suitable than the cluster ones (and I haven't seen any > single LED MR11s anywhere as yet).
I don't think it's really possible to make that generalisation.
> Otherwise, I'm also considering the EL530 for commuting -- roads both > lit and unlit, and off-road lit and unlit (but on a good surface).
I think any 1W LED is going to be marginal for off-road use, but this obviously depends on the surface and speeds involved. If you want cheap and useful off-road, halogen lights may be your best bet.
As for on road, I think you can do better than an EL530 at the price (see my other posts here for details).
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