Bike lights

Discussion in 'Cycling Equipment' started by Robert, Jul 26, 2003.

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  1. Robert

    Robert Guest

    Is it me or when I use my brand new NiMHs my light seems to dim so much sooner than when I throw in
    your average alkalines? I like the rechargablity of the the new batts, but, if they get me home....
    I get almost three night rides to almost one on the old alkaline batteries
    v. the new NiMH. My light is cheap but I'd like to see the road towards the end as it's the
    unlighted part. I'd also like longer battery life. But, I'm not going to drop two bones on a new
    water bottle cell.

    Rob
     
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  2. Peter

    Peter Guest

    Robert wrote:
    > Is it me or when I use my brand new NiMHs my light seems to dim so much sooner than when I throw
    > in your average alkalines?

    It's likely you're seeing the results of two different effects. First is that the current capacity
    in mA-hrs of alkalines is higher than that of many NiMH cells. Check the capacity rating of your
    cells. Good NiMH AA cells now are over 2000 mA-hr which should come close to that of alkalines which
    have a capacity of about 2800 mA-hr for low current applications but drop when used at higher
    currents like typical bike lights.

    The second effect is that the two types of cells act very differently when they get near the end of
    their capacity. Alkalines start at 1.5 V and slowly drop as they are discharged, so your bike light
    will slowly get dimmer and dimmer. As the voltage drops, the current drawn by the bike light will
    also decrease, allowing the alkaline cell to operate the light for a longer time albeit at greatly
    reduced brightness. In contrast, NiMH cells start out at about 1.35 V, drop rapidly to 1.2 V and
    then stay almost constant until they're almost completely discharged at which point they drop
    rapidly to 0. So your bike light will stay at constant brightness for some period of time and then
    go out very quickly. With alkalines you can frequently still make it home after the light starts to
    dim, but with NiMH you'd better have a spare set of cells along since the light will go out very
    soon after you notice the first sign of dimming.

    I wouldn't give up on the NiMH cells - just get one or two spare sets so you can swap them as needed
    - it'll still be much cheaper than alkalines overall. And check the capacity ratings of the ones you
    buy - for AAs it should at least be close to 2000 mA-hr if not above that.
    > I like the rechargablity of the the new batts, but, if they get me home.... I get almost three
    > night rides to almost one on the old alkaline batteries
    > v. the new NiMH. My light is cheap but I'd like to see the road towards the end as it's the
    > unlighted part. I'd also like longer battery life. But, I'm not going to drop two bones on a
    > new water bottle cell.
    >
    > Rob
     
  3. Werehatrack

    Werehatrack Guest

    On Sun, 27 Jul 2003 05:07:59 GMT, Peter <[email protected]> may have said:

    >Robert wrote:
    >> Is it me or when I use my brand new NiMHs my light seems to dim so much sooner than when I throw
    >> in your average alkalines?
    >
    >...NiMH cells start out at about 1.35 V, drop rapidly to 1.2 V and then stay almost constant until
    >they're almost completely discharged at which point they drop rapidly to 0.

    As a result of the lower voltage, many headlights will be perceptibly dimmer at the start of the
    discharge cycle of NiMH cells than during the last half of the alkaline discharge. Thus, you may
    notice that NiMH batteries just never give you what you expect.

    In some applications, it is necessary to use 5 NiMH cells to get the same result as with 4 alkaline
    cells. 4X1.2=4.8, 4x1.5=6, 5x1.2=6. The math is inescapable.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
    don't respond to something, it's also possible that I'm busy.
     
  4. James Annan

    James Annan Guest

    Werehatrack wrote:

    > In some applications, it is necessary to use 5 NiMH cells to get the same result as with 4
    > alkaline cells. 4X1.2=4.8, 4x1.5=6, 5x1.2=6. The math is inescapable.

    But you've forgotten the internal resistance, which is much greater for alkalines than for
    rechargeables, and which results in the voltage across the bulb being a fair bit lower than the
    nominal 1.5V per cell in that case.

    James
     
  5. Werehatrack

    Werehatrack Guest

    On Sun, 27 Jul 2003 17:30:27 +0900, James Annan <[email protected]> may have said:

    >Werehatrack wrote:
    >
    >> In some applications, it is necessary to use 5 NiMH cells to get the same result as with 4
    >> alkaline cells. 4X1.2=4.8, 4x1.5=6, 5x1.2=6. The math is inescapable.
    >
    >But you've forgotten the internal resistance, which is much greater for alkalines than for
    >rechargeables, and which results in the voltage across the bulb being a fair bit lower than the
    >nominal 1.5V per cell in that case.

    In sufficiently high draw applications, but I this is not one of them. Not even close. My photo
    flash equipment (whose load on the batteries is incredible; 6 alkaline AA units can be run flat in
    under an hour) tells me that the alkalines have a better delivery curve per cell at drain rates far
    faster than a bike headlight. The recharge time for my big flash remains reasonably fast (indicating
    that the delivered voltage is still high) for about 2/3 of the life of the alkalines, but it's
    unacceptably slow right from the start with the NiMH units unless I plug in the adapter that allows
    me to use 8 NiMH units in place of the 6 alkalines. Then the NiMH units work the same as the fresh
    alkalines for their entire charge...but they still run down to zip sooner. For a short shoot, under
    100 exposures or where the ambient light level is decent, I can go with the NiMH pack alone, but if
    I'm going to be doing a 200-shot package or if I know that the location is dark, I bring the
    alkaline pack to swap in when the NiMH pack runs down. (Swapping the batteries in the pack is a pain
    in the neck, so I don't bother keeping two sets of NiMH cells for it.) Thus it's apparent that even
    at the very fast drain levels of my equipment, the alkalines maintain a higher delivered voltage per
    cell than the NiMH units. Bike headlights have a much longer runtime than my flash, therefore their
    drain has got to be lower, so the alkalines are going to work even better. This is fully consistent
    with what people who've tried swapping to NiMH batteries for flashlights have reported as well.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
    don't respond to something, it's also possible that I'm busy.
     
  6. NO rechargeable will last as long as a similar sized alkaline. Even the rechargeable alkalines
    don't, but they're close.

    The advantage is you can recharge them and use them again, and again, and... you get the picture.

    I keep two sets. One in the lights, one, fully charged I carry when I know set being used is near
    it's discharge time.

    When the first wears down, I exchange the recharged for the discharged, and recharge the discharged
    while using the recharged!

    May you have the wind at your back. And a really low gear for the hills! Chris

    Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner
     
  7. Chris Zacho "The Wheelman" <[email protected]> wrote in message
    news:[email protected]...
    > NO rechargeable will last as long as a similar sized alkaline. Even the rechargeable alkalines
    > don't, but they're close.
    >
    > The advantage is you can recharge them and use them again, and again, and... you get the picture.
    >
    > I keep two sets. One in the lights, one, fully charged I carry when I know set being used is near
    > it's discharge time.
    >
    > When the first wears down, I exchange the recharged for the discharged, and recharge the
    > discharged while using the recharged!
    >
    > May you have the wind at your back. And a really low gear for the hills! Chris
    >
    > Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner

    I have the cateye el300 as my backup light- what bugs me about the light is there is no provision
    for using rechargeables in the thing- no place for the 5th cell that would alow you to have full
    voltage . I can "only" use the thing for mebbe 4 hrs before the light gets noticeably dim and it's
    tiime for the fresh set.Wish some of the light makers would allow a configurable battery
    arrangement depending on what you have 4 for alkalines,5 for nimh/nicad.
     
  8. James Annan

    James Annan Guest

    Werehatrack wrote:
    > On Sun, 27 Jul 2003 17:30:27 +0900, James Annan <[email protected]> may have said:
    >
    >
    >>Werehatrack wrote:
    >>
    >>
    >>>In some applications, it is necessary to use 5 NiMH cells to get the same result as with 4
    >>>alkaline cells. 4X1.2=4.8, 4x1.5=6, 5x1.2=6. The math is inescapable.
    >>
    >>But you've forgotten the internal resistance, which is much greater for alkalines than for
    >>rechargeables, and which results in the voltage across the bulb being a fair bit lower than the
    >>nominal 1.5V per cell in that case.
    >
    >
    > In sufficiently high draw applications, but I this is not one of them. Not even close.

    Well the only figures I have seen (in the bikecurrent FAQ) say a cateye micro bulb sees 4.8-5.2V off
    4 alkalines (6V nominal), and presumably most 3V (therefore twice the current drawn for the same
    typical 2.4-3W output) will be worse.

    I've seen a figure for typical internal resistance of an AA alkaline as .4 Ohms, so you can do your
    own sums (but although this figure seems to have been competently estimated, it doesn't seem to
    match the results above for the bike light).

    I am surprised by your results for the flashgun as it is contradicted by almost everything I have
    heard about using different cell types in digital cameras (another high current application), plus
    my own experience of the same. Of course alkalines do have a greater total capacity and basic
    voltage supplied, so there is no question that they will perform better in some applications.

    James
     
  9. "patrick mitchel" wrote:

    > I have the cateye el300 as my backup light- what bugs me about the light is there is no provision
    > for using rechargeables in the thing- no place for the 5th cell that would alow you to have full
    > voltage . I can "only" use the thing for mebbe 4 hrs before the light gets noticeably dim and
    > it's tiime for the fresh set.Wish some of the light makers would allow a configurable battery
    > arrangement depending on what you have 4 for alkalines,5 for nimh/nicad.

    I use a Cateye HL-1600. This is a 6V, 2.4W halogen light designed to use rechargable NiCd or
    NiMH cells.

    It takes 5 cells (to yield about 6V), has a standard low voltage DC socket (+ve tip) so that the
    batteries can be recharged in situ, and also has a small red "low battery" warning LED.

    By using a shorted dummy cell, 4 standard alkaline cells would work fine in this (as long as you
    didn't try to recharge them).

    BTW, here in Australia, it's supplied with neither batteries nor charger. I use a 6V (5 cell) NiMH
    cellular phone charger. This recharges my 2000 mAh NiMH cells within a couple of hours,
    automatically dropping back to a long-term maintenance trickle charge rate.

    John
     
  10. Werehatrack

    Werehatrack Guest

    On Mon, 28 Jul 2003 06:35:22 +0900, James Annan <[email protected]> may have said:

    >I've seen a figure for typical internal resistance of an AA alkaline as .4 Ohms, so you can do your
    >own sums (but although this figure seems to have been competently estimated, it doesn't seem to
    >match the results above for the bike light).

    I see this all the time in the battery area. The specs say one thing, the results say something
    entirely different. It has never made any sense to me, and I've learned that the only way to find
    out if a given battery/device combination is viable is to try it and see. There have been some
    *expensive* disappointments in that area over the years. Most recently, it turned out that a lithium
    ion battery pack rated for 20F was actually much too temperature sensitive to power my digital
    camera in sub-freezing outdoor work; I had to build an extension cord and use a cobbled-together
    alkaline pack in an inner pocket of my jacket. That worked, but it was still aggravating.

    >I am surprised by your results for the flashgun as it is contradicted by almost everything I have
    >heard about using different cell types in digital cameras (another high current application), plus
    >my own experience of the same. Of course alkalines do have a greater total capacity and basic
    >voltage supplied, so there is no question that they will perform better in some applications.

    Digitals are another entirely different bunch; I've noticed that many of them tend to be quite
    finicky about their power. I've been waiting for the SLR bodies to drop within my range before
    getting another one; I've been underwhelmed by the rangefinder models I've used so far since not a
    dratted one of them provides a manual focus method.

    I think the flashgun works as it does in part because the demand decay matches the supply decay to a
    certain extent; the alkalines deliver a surge before the voltage starts to fall, and the demand from
    the flash is highest for the 1 to 1.5 seconds after the unit fires; it tapers to a very low load
    after 3 to 4 seconds with fresh alkalines or with the 8-cell NiMH pack. The NiMH batteries I've been
    using have a remarkably *constant* supply capability, with almost immediate voltage fall-off under
    surge load. Interestingly, the manufacturer used to supply a 6-cell NiMH holder for this unit which
    had a different power contact arrangement so that it was better matched to the circuitry, but my
    experience with it was less than stunning to say the least. That's why I built the 8-cell external
    pack. (I can't *quite* justify a Quantum for this beast, but I may eventually end up buying one.)

    Anyway, back on topic (sort of), I got a look at the "beam" pattern from the Cateye 5-LED unit
    today, and I think I'll keep shopping. It's better than I had feared, not as good as I had hoped,
    and not *quite* enough for what I need. The mass-produced tech in that area is getting close to
    making a really useful product, though. In a few more years, I think we'll see a different picture.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
    don't respond to something, it's also possible that I'm busy.
     
  11. Werehatrack

    Werehatrack Guest

    On Mon, 28 Jul 2003 08:51:47 +1000, "John Henderson" <[email protected]> may have said:

    >"patrick mitchel" wrote:
    >
    >> I have the cateye el300 as my backup light- what bugs me about the light is there is no
    >> provision for using rechargeables in the thing- no place for the 5th cell that would alow you to
    >> have full voltage . I can "only" use the thing for mebbe 4 hrs before the light gets noticeably
    >> dim and it's tiime for the fresh set.Wish some of the light makers would allow a configurable
    >> battery arrangement depending on what you have 4 for alkalines,5 for nimh/nicad.
    >
    >I use a Cateye HL-1600. This is a 6V, 2.4W halogen light designed to use rechargable NiCd or
    >NiMH cells.
    >
    >It takes 5 cells (to yield about 6V), has a standard low voltage DC socket (+ve tip) so that the
    >batteries can be recharged in situ, and also has a small red "low battery" warning LED.
    >
    >By using a shorted dummy cell, 4 standard alkaline cells would work fine in this (as long as you
    >didn't try to recharge them).
    >
    >BTW, here in Australia, it's supplied with neither batteries nor charger. I use a 6V (5 cell) NiMH
    >cellular phone charger. This recharges my 2000 mAh NiMH cells within a couple of hours,
    >automatically dropping back to a long-term maintenance trickle charge rate.

    Neat. That model is available around here; I may have to give it a look. I like the idea of being
    able to swap between the 4/Alk and
    5/Ni cell configs using a dummy, and since I already have a couple of the requisite shorting cells,
    it provides another alternative.

    --
    My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
    don't respond to something, it's also possible that I'm busy.
     
  12. James Annan

    James Annan Guest

    "John Henderson" <[email protected]> wrote in message
    news:<[email protected]>...
    >
    > I use a Cateye HL-1600. This is a 6V, 2.4W halogen light designed to use rechargable NiCd or
    > NiMH cells.
    >
    > It takes 5 cells (to yield about 6V), has a standard low voltage DC socket (+ve tip) so that the
    > batteries can be recharged in situ, and also has a small red "low battery" warning LED.
    >
    > By using a shorted dummy cell, 4 standard alkaline cells would work fine in this (as long as you
    > didn't try to recharge them).

    No, it might work but it would be significantly undervolted and therefore rather dim. I suppose it
    depends on your definition of 'fine'. With 5 alkalines, it would be about 10% overvolted which could
    in fact be pretty handy assuming that the bulb really is rated for a long life at 6V2.4W.
    Overvolting (relative to the manufacturer's recommendation) increases efficiency at the cost of
    lower bulb life, which is often a good trade-off for cyclists - however this depends what the
    manufacturer had in mind with the original rating!

    James
     
  13. patrick mitchel wrote:
    > I have the cateye el300 as my backup light- what bugs me about the light is there is no provision
    > for using rechargeables in the thing- no place for the 5th cell that would alow you to have full
    > voltage . I can "only" use the thing for mebbe 4 hrs before the light gets noticeably dim and
    > it's tiime for the fresh set.Wish some of the light makers would allow a configurable battery
    > arrangement depending on what you have 4 for alkalines,5 for nimh/nicad.

    Have you tried Energizer Lithium AA's? They are not rechargable but I find they last a lot longer
    than alkalines in almost everything. You can usually find them at Home Depot. They're a little more
    expensive but I find that in high drain devices, the longer life more than offsets that. I should
    warn you that they also don't lose voltage until just before their death. When they start to dim,
    you'll probably only have a few seconds or minutes at the most. They also have better cold weather
    performance and longer shelf life (good for a backup light that rarely gets used).

    I've been thinking about getting an EL-300 as a backup and using lithiums. I'm curious as to how
    well it would work out.

    --Bill Davidson
    --
    Please remove ".nospam" from my address for email replies.

    I'm a 17 year veteran of usenet -- you'd think I'd be over it by now
     
  14. Rwm

    Rwm Guest

    Mine is bigger than yours

    "Werehatrack" <[email protected]> wrote in message
    news:[email protected]...
    > On Sun, 27 Jul 2003 05:07:59 GMT, Peter <[email protected]> may have said:
    >
    > >Robert wrote:
    > >> Is it me or when I use my brand new NiMHs my light seems to dim so much sooner than when I
    > >> throw in your average alkalines?
    > >
    > >...NiMH cells start out at about 1.35 V, drop rapidly to 1.2 V and then stay
    almost
    > >constant until they're almost completely discharged at which point they drop rapidly to 0.
    >
    > As a result of the lower voltage, many headlights will be perceptibly dimmer at the start of the
    > discharge cycle of NiMH cells than during the last half of the alkaline discharge. Thus, you may
    > notice that NiMH batteries just never give you what you expect.
    >
    > In some applications, it is necessary to use 5 NiMH cells to get the same result as with 4
    > alkaline cells. 4X1.2=4.8, 4x1.5=6, 5x1.2=6. The math is inescapable.
    >
    > --
    > My email address is antispammed; pull WEEDS if replying via e-mail. Yes, I have a killfile. If I
    > don't respond to something, it's also possible that I'm busy.
     
  15. Rwm

    Rwm Guest

    No mine is!

    "James Annan" <[email protected]> wrote in message news:[email protected]...
    > Werehatrack wrote:
    >
    > > In some applications, it is necessary to use 5 NiMH cells to get the same result as with 4
    > > alkaline cells. 4X1.2=4.8, 4x1.5=6, 5x1.2=6. The math is inescapable.
    >
    > But you've forgotten the internal resistance, which is much greater for alkalines than for
    > rechargeables, and which results in the voltage across the bulb being a fair bit lower than the
    > nominal 1.5V per cell in that case.
    >
    > James
     
  16. James Annan

    James Annan Guest

    Werehatrack <[email protected]> wrote in message
    news:<[email protected]>...
    > On Mon, 28 Jul 2003 06:35:22 +0900, James Annan <[email protected]> may have said:
    >
    > >I've seen a figure for typical internal resistance of an AA alkaline as .4 Ohms, so you can do
    > >your own sums (but although this figure seems to have been competently estimated, it doesn't seem
    > >to match the results above for the bike light).
    >
    > I see this all the time in the battery area. The specs say one thing, the results say something
    > entirely different.

    It wasn't 'specs', it was tests by interested (and obviously expert) hobbyists and to correct my
    previous mistake, the figure of 0.4 Ohms per cell _does_ match closely with the results for the
    cateye light I also quoted (eg 4.8V2.4W bulb is 9.6 ohms, so with 4xAA cells the circuit is 11.2
    ohms, 6V, .54A and the bulb is slightly overvolted at
    5.1V, in agreement with the measurements [that's with fresh cells]).

    What I did miss is that the light that the original poster was talking about is not an incandescent
    but an LED light with low current draw and long life (when used with alkalines). Some of these work
    fine with rechargeables too (I've used several with no problems), but some may be fussy about the
    voltage, depending on the particular requirements of the LEDs usd and any internal electronics.

    > I think the flashgun works as it does in part because the demand decay matches the supply decay to
    > a certain extent; the alkalines deliver a surge before the voltage starts to fall, and the demand
    > from the flash is highest for the 1 to 1.5 seconds after the unit fires; it tapers to a very low
    > load after 3 to 4 seconds with fresh alkalines or with the 8-cell NiMH pack.

    Ie it takes a high current at first but perhaps _also_ needs a high voltage/low current to fully
    charge? I'd wondered about that (just consider a capacitor across the battery - it will never get
    charged to 6V with rechargeables). Of course it may have any other amount of fancy electronics
    inside too. But this is not relevant to normal incandescent bike lights which is what I (mistakenly)
    though the thread was about!

    James
     
  17. Shaun Rimmer

    Shaun Rimmer Guest

    Peter <[email protected]> wrote in message news:p[email protected]...

    > The second effect is that the two types of cells act very differently when they get near the end
    > of their capacity. Alkalines start at 1.5 V and slowly drop as they are discharged, so your bike
    > light will slowly get dimmer and dimmer. As the voltage drops, the current drawn by the bike light
    > will also decrease,

    I think you may be missing a point here (or I am - head ain't all it usually is at the moment) -
    when a bulb gets dimmer (cooler) the resistance of the filament drops, and this speeds up the
    final draining of the battery (leaving out that it's voltage is less), so even though the battery
    voltage dropping would decrease it's discharge rate through a resistor of fixed value, in this
    instance, it 'sorta' ballances out 'for all intents and purposes' (no measurements to give numbers
    - sorry geeks!). 'Over-volting' of halogen bulbs increases battery life for given light output at
    the expense of bulb life, because a hotter bulb has a greater resistance than a cooler one of the
    same spec.

    > allowing the alkaline cell to operate the light for a longer time albeit at greatly reduced
    > brightness.

    The starting voltage might be making more difference here. As someone else suggested, for 6 volt
    lights, there should be another cell in the pack if using NiMH, or indeed NiCAD.

    Shaun aRe - WTF is wrong with big, solid, heavy SLA's anyway? Heheheheh (what I use........)......
     
  18. Peter

    Peter Guest

    Shaun Rimmer wrote:

    > Peter <[email protected]> wrote in message news:p[email protected]...
    >
    >
    >>The second effect is that the two types of cells act very differently when they get near the end
    >>of their capacity. Alkalines start at 1.5 V and slowly drop as they are discharged, so your bike
    >>light will slowly get dimmer and dimmer. As the voltage drops, the current drawn by the bike light
    >>will also decrease,
    >
    >
    > I think you may be missing a point here (or I am - head ain't all it usually is at the moment) -
    > when a bulb gets dimmer (cooler) the resistance of the filament drops, and this speeds up the
    > final draining of the battery (leaving out that it's voltage is less), so even though the battery
    > voltage dropping would decrease it's discharge rate through a resistor of fixed value, in this
    > instance, it 'sorta' ballances out 'for all intents and purposes' (no measurements to give numbers
    > - sorry geeks!).

    It's true that the resistance will decrease, but it doesn't do so enough to balance things out. The
    current flowing through the bulb will still get less as the voltage drops - just not as much less as
    it would if the resistance were constant. Of course all this talk of filaments is irrelevant to the
    original poster who was using an LED light, not an incandescent.

    > 'Over-volting' of halogen bulbs increases battery life for given light output at the expense of
    > bulb life, because a hotter bulb has a greater resistance than a cooler one of the same spec.

    A hotter bulb will be more efficient at producing visible light with a smaller percentage of the
    energy wasted on emissions in the infrared (heat) part of the spectrum. With incandescent bulbs the
    character of the light will also change with the color shifting toward the blue end of the spectrum.
    Since incandescents usually put out light that's more yellow than sunlight this shift results in a
    more natural light.
    >
    >
    >>allowing the alkaline cell to operate the light for a longer time albeit at greatly reduced
    >>brightness.
    >
    >
    > The starting voltage might be making more difference here. As someone else suggested, for 6 volt
    > lights, there should be another cell in the pack if using NiMH, or indeed NiCAD.

    This will certainly help the light's brightness during the main portion of its operation, but won't
    change the fact that both NiMH and NiCd cells die very suddenly whereas alkalines have a more
    gradual voltage decline. With NiMH/NiCd cells it's essential to have a spare set on hand and swap
    them out as soon as any dimming is noticed while with alkalines there's frequently enough time to
    still make it home with enough light to be seen although it might not be enough to see the road.
     
  19. Bill Davidson <[email protected]> wrote in message news:%[email protected]...
    > patrick mitchel wrote:
    > > I have the cateye el300 as my backup light- what bugs me about the
    light is
    > > there is no provision for using rechargeables in the thing- no place for
    the
    > > 5th cell that would alow you to have full voltage . I can "only" use the thing for mebbe 4 hrs
    > > before the light gets noticeably dim and it's
    tiime
    > > for the fresh set.Wish some of the light makers would allow a
    configurable
    > > battery arrangement depending on what you have 4 for alkalines,5 for nimh/nicad.
    >
    > Have you tried Energizer Lithium AA's? They are not rechargable but I find they last a lot longer
    > than alkalines in almost everything. You can usually find them at Home Depot. They're a little
    > more expensive but I find that in high drain devices, the longer life more than offsets that. I
    > should warn you that they also don't lose voltage until just before their death. When they start
    > to dim, you'll probably only have a few seconds or minutes at the most. They also have better cold
    > weather performance and longer shelf life (good for a backup light that rarely gets used).
    >
    > I've been thinking about getting an EL-300 as a backup and using lithiums. I'm curious as to how
    > well it would work out.
    >
    > --Bill Davidson
    > --
    > Please remove ".nospam" from my address for email replies.
    >
    > I'm a 17 year veteran of usenet -- you'd think I'd be over it by now
    Regarding the EL300- emphasis on the "backup" my primary is a Bisy-what a wonderful - yet frugal
    light. The pattern is wonderful- it illuminates the bike path I ride better than anything I've
    futzed around with.And that with a pr18 bulb and a makita 9.6 drill battery pack- that puts out
    perhaps a mighty 3 watts of power. Far better than the narrow diffuse beam of the EL300. I don't
    have the experience with LED's to say that they are inferior to the incandescent only that for me
    the Bisy shows the way- literally.
     
  20. "James Annan" wrote:

    > No, [using 4 alkaline cells with a 6V bulb] might work but it would be significantly undervolted
    > and therefore rather dim. I suppose it depends on your definition of 'fine'. With 5 alkalines, it
    > would be about 10% overvolted which could in fact be pretty handy assuming that the bulb really is
    > rated for a long life at 6V2.4W. Overvolting (relative to the manufacturer's recommendation)
    > increases efficiency at the cost of lower bulb life, which is often a good trade-off for cyclists
    > - however this depends what the manufacturer had in mind with the original rating!

    I agree with the technical points, but will continue to make the more conservative recommendation.

    As an aside, the fast "intelligent" NiMH charger I found which works perfectly with my Cateye
    HL-1600 is Cat. No. ZA0100 from http://www.oatleyelectronics.com/battery.html (you need to make up a
    cable). Prices are in Australian dollars.

    John
     
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