The Light Thread

Discussion in 'Commuting and Road Safety' started by mrkott3r, Aug 3, 2006.

  1. mrkott3r

    mrkott3r New Member

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    Sorry if a really good thread exists on this topic, it seems search isn't working for me.

    The more I look at light sets the more confused I become.

    I want to buy a rechargeable light set for commuting (obviously at night) I rock a roadie so something bright is important. I also want to go the decent rechargeable route because I can feel a strong urge to take up night time mountain bike riding in the future.

    So Ive been diggin away on the internet and into the bike stores, but Ive got questions:
    1) It looks like with these light sets you are paying for the battery. true/false?
    2) For a light set does the difference between a NiMH and Li-on really matter? Li-On is a better technology but it has its drawbacks too like not lasting as long (ask any iPod owner) but NiMH does have a memory effect.
    3) When the battery does fail, can you buy replacements or is it cheaper to buy a new light set.
    4) What rechargeable light set do you use?
    5) Suggest me a light set around the $150-$250 mark.
    6) What do you use for rear lighting?

    Thanks guys
     
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  2. rek

    rek New Member

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    For commuting, I've found a 10W halogen light is just fine for going at speeds up to about 30kph.

    For night mountain biking, more light is always better -- and a helmet mount for the light is also a nice option. I haven't bothered to set mine up as one, despite having the mount kit (came with the lights), but people I know who have done so really like it.

    For the most part, yes. However some light sets have more advanced electronics that give you an accurate gauge of how much time is left, a special "reserve charge" to get you home, and super duper fast-turbo-smart chargers, etc. All this stuff drives up the price.

    And if you are looking for a HID (car 'xenon headlight' type bulb) then that's where another few hundred dollars go. Just a note with HID lights; the high voltage ballast circuit creates quite a bit of EM interference and can knock out heart rate monitors and wireless speedometers etc.

    Unless you are paranoid about being seen, or just really want the most light available, HIDs are overkill for commuting. Great for technical off-roading in pitch black darkness though.

    LiIon is lighter and has a greater charge density. For a given physical dimension, the LiIon will be both lighter, and hold more charge, than a NiMH battery. Unless you want something that is really light and lasts a long time, it's not much of a muchness. Both my light sets are NiMH battery based and have no regrets buying them over their more expensive LiIon versions.

    Neither modern NiMH nor LiIon suffer from the 'traditional' memory effect, but of course they degrade like all rechargable batteries do, and improper handling or overcharging will cause symptoms that will appear similar to memory effect. Because of this it's wise to give preference to a light unit that gives you a 'smart' charger -- that way you can just leave it plugged in overnight/all day, and not worry about overcharging.

    Strange but true fact about LiIon batteries: the battery cells actually cope better with a usage pattern that involves many partial discharges, rather than a deep discharge.

    Some cheap light units use sealed lead acid batteries; these are really heavy (as in, an extra kilogram heavier) but cheap to replace should anything go bad.

    Yes you can buy a replacement battery from the manufacturer. If you're technically inclined you may even be able to crack open the casing of the battery and replace the individual cells.

    The battery units are usually specced to have a usable life span of several hundred recharge cycles; 300-500 cycles is a common quoted figure.

    If you think about it, even if you use them as much as you could in typical commuting -- 5 times (days) a week, recharging after every ride, all through Winter and half of Autumn and Spring -- 300-500 cycles would mean 3.5 to 5.5 years of service life.

    And that's if you used them every Wintery day in that time.

    I really like the Light & Motion (http://www.bikelights.com/) light sets, as they are built really well, are light, and have a lot of small but useful things in their design. For example, the lights are designed so that if you crash and the lights take a severe blow, the light unit doesn't take the full force: instead it's all directed towards completely annihilating a 10 cent piece of plastic, which you can replace yourself. (They give you a few spares with the light.) I have umm.. "tested".. this feature accidentally, and it works exactly as it should. After replacing the crash washer (5 seconds work with a philips screwdriver), everything was as good as new.

    For my commuter I have a Light & Motion Commuter light (makes sense eh! ;) ) It's a 10W halogen with a small, light NiMH battery which can fit into nice nooks and crannies; I have mine wedged in the junction between the seat tube and seat stays. It has no special electronic wizardry and is supposed to come with a dumb trickle charger, but for some reason mine came with a 'smart' charger. The NiMH battery lasts for 2 hours.

    On my MTB I have a Light & Motion ARC 13W HID light which provides more light than you'd ever imagine you'd need, and has wizardry electronics to change the beam strength/power usage, and gives you a 30 minute 'reserve charge' warning. It uses a NiMH battery that lasts for 3 hours, 3.5 on 'low power' (which funnily enough isn't really much less light than full power). There are LiIon versions that can last over 6 hours should you feel the need to go 24 hour solo racing or something silly like that ;)

    Unfortunately they don't make the Light & Motion Commuter anymore :(

    However there are many lights in your price range that use NiMH batteries and offer 10 to 15 watts of halogen light. These should be a fine choice for commuting.

    Unless you have a local bike store that is running a sale on lights, you'll get best value by buying from an online shop. I've dealt with these shops and they have good deals on lights:

    http://www.phantomcycles.com.au/home.php?cat=10 (I bought both my lights from these guys)

    http://www.torpedo7.com/page/australia/CTGY/lights-accessories

    http://www.deanwoods.com.au/store/category108_1.htm

    A rather large multi-LED rear red flashing light, as well as one of those tiny one-LED flashing light thingys that I have strapped to the back of my helmet.
     
  3. rek

    rek New Member

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  4. mrkott3r

    mrkott3r New Member

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    thanks for the useful info.
    Im just a little pissed off with my iPod battery, hardly 12 months out of it and I know the battery has degraded significantly.

    Yeah I thought HID is overkill (price certainly is).
     
  5. athoma00

    athoma00 New Member

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    I don't really use a rechargeable light but am going to add my 0.02. IMO a system in which you can replace the batteries would be ideal, i.e. one using maybe AA nimh batteries. That way when they eventually deteriorate you can easily replace them instead of paying big $ for a replacement battery pack. I'm not sure whats out there which would meet that requirement though.
     
  6. mrkott3r

    mrkott3r New Member

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    another question:
    whats the difference between a 6volt and 12volt system?
     
  7. rek

    rek New Member

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    In terms of light output, nothing really. The wattage and bulb type is what matters.
     
  8. matagi

    matagi Well-Known Member

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    6 volt system requires heavier guage wiring.
     
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