The big LIGHTS thread 2011-2014

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  • Ouija
    Ouija Posts: 1,386
    Just buy two of these and duck tape them together (lengthwise) into a elongated brick and use the Y-Splitter to merge them into one giant parallel connected battery (puts less strain on each cell as fewer amps are being drawn from any cell at any given moment, which in turn actually gets more runtime out of them as most protection circuits will actually cut power if you try and draw too much ampage at once on some packs). Or just buy one and Y-Splitter merge it with your current pack to make a 10 cell pack.
  • Neal_
    Neal_ Posts: 477
    Ouija wrote:
    Just buy two of these and duck tape them together (lengthwise) into a elongated brick and use the Y-Splitter to merge them into one giant parallel connected battery (puts less strain on each cell as fewer amps are being drawn from any cell at any given moment, which in turn actually gets more runtime out of them as most protection circuits will actually cut power if you try and draw too much ampage at once on some packs). Or just buy one and Y-Splitter merge it with your current pack to make a 10 cell pack.

    I think that is a 12.6V pack so won't be suitable for my light but they also do an 8.4V 6 cell pack (http://www.lightmalls.com/8-4v-4400mah- ... ycle-light) for £13...problem is they are only offering FedEx delivery which is an extra tenner so 2 packs would be £36ish and from my experience of Lighmalls cells I'd rather spend that on a Magicshine 6 cell pack from the UK. I've already ordered that 2 pack splitter though so hopefully that will extend the run time for the 2 packs I've got at the moment, thanks again for suggesting them.
  • roverthehill
    roverthehill Posts: 155
    simple question here!

    Looking a cheap rear light. Ideally something with a rechargable battery. Don't really ride the roads but just want something a little better than what I currently have.

    Cheers

    D
  • diy
    diy Posts: 6,473
    If you want something a bit brighter than normal them the Smart Lunar R1 is good and you can get them for a bout a tenner. If its off road then a couple of whatever you can get for under a fiver:

    http://www.chainreactioncycles.com/Mode ... elID=70377
    http://www.chainreactioncycles.com/Mode ... elID=56550
    http://www.chainreactioncycles.com/Mode ... elID=56546
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  • Ouija
    Ouija Posts: 1,386
    Neal_ wrote:

    I think that is a 12.6V pack so won't be suitable for my light but they also do an 8.4V 6 cell pack (http://www.lightmalls.com/8-4v-4400mah- ... ycle-light) for £13...problem is they are only offering FedEx delivery which is an extra tenner so 2 packs would be £36ish and from my experience of Lighmalls cells I'd rather spend that on a Magicshine 6 cell pack from the UK. I've already ordered that 2 pack splitter though so hopefully that will extend the run time for the 2 packs I've got at the moment, thanks again for suggesting them.

    Don't know what the diameter of your reflector is but you might want look into something like this....

    sku_11921_1.jpg
  • -Archie-
    -Archie- Posts: 152
    Ouija wrote:
    As soon as some manufacturer realizes that a multi-head light should run at 4v, instead of 8v,
    That would be quite bad idea.
    then you could half the number of batteries you'd need to run them.
    And also, cut the runtime. :)
  • -Archie-
    -Archie- Posts: 152
    Neal_ wrote:
    I’m fairly certain the extra battery pack that appeared to be a Magicshine pack with BAK cells is just a cheap poor quality pack in a waterproof cover.
    Bad news...
    I don’t have a multimeter yet to get a better idea of what is happening but I’m wondering if the protection circuit is cutting in too early as the light wasn’t dimming.
    At least in my LightMalls battery, the problem is definitely not in the protection PCB: it disconnects correctly, at 3.0 volt per half. The cells themselves are junk.
    As it is my 3xT6 light isn’t very useful for the length of rides I do so not sure whether to try out this battery pack 8.4V 10000mAh 4x26650 Battery Set For LED Bike Light which specifically states ” it can runing more than 200minutes at 3T6 bike light on high mode” for £20ish or spend £40ish on an official UK stock Magicshine pack with BAK cells??? It’s not turning out to be the easy cheap solution I had hoped :roll:
    IMHO, there's enough information to stop experimenting with LightMalls batteries of any kind. On the other hand, all the MagicShine ones I've ever bought, were of quite good quality: matching or exceeding advertised capacity.
  • Ouija
    Ouija Posts: 1,386
    -Archie- wrote:
    Ouija wrote:
    As soon as some manufacturer realizes that a multi-head light should run at 4v, instead of 8v,
    That would be quite bad idea.
    then you could half the number of batteries you'd need to run them.
    And also, cut the runtime. :)

    Like to know how you come by that conclusion?
  • -Archie-
    -Archie- Posts: 152
    Amount of energy stored in two cells is approximately two times more than in single cell. :) Moreover, increase of current (to provide equal power to the load) will also impact the capacity, so actual decrease of runtime will be even greater then two times. Another problem - running the system in such "low voltage / high current" setup will require thick wires, specifically designed connectors (like ones used in radio-controlled planes etc), and so on. The only case when 4 volt system is acceptable is a torch, with direct connection of cell to the load.
  • Ouija
    Ouija Posts: 1,386
    I was always under the impression that two parallel connected 18650 cells double the capacity but not the current and two series connected 18650 cells give twice the current but not twice the capacity? And, therefore, a 4v @ 2.0 amps XML-T6 running off four parallel connected 18650 batteries (8800mAh) would give more run time than a 8v @ 2.0 amps XML-T6 running of two Series / two parallel connected batteries (4400mAh).

    Certainly, my Kenesis Maxlight commuting bike currently has a 8V magicshine copy running off two 44000mAh battery packs joined together via a Y-Splitter cable (4 series / 4 parallel) on one side of the stem and a 4v magicshine copy running off a homemade battery pack (4 parallel) on the other. Both appear to give me 6 hours run times and roughly the same brightness. So what's that all about?.....
  • -Archie-
    -Archie- Posts: 152
    Ouija, in previous post you were talking about reducing the number of batteries by half, but now - about rearranging the same quantity in different way, so it's a bit difficult to follow your idea...
    I was always under the impression that two parallel connected 18650 cells double the capacity but not the current
    Capacity will be doubled, but current from each cell reduced by half for the same load.
    and two series connected 18650 cells give twice the current but not twice the capacity?
    It will not affect capacity nor current, but will double the voltage.
    Certainly, my Kenesis Maxlight commuting bike currently has a 8V magicshine copy running off two 44000mAh battery packs joined together via a Y-Splitter cable (4 series / 4 parallel) on one side of the stem and a 4v magicshine copy running off a homemade battery pack (4 parallel) on the other. Both appear to give me 6 hours run times and roughly the same brightness. So what's that all about?.....
    It's all about physics! :) As long as you don't provide exact capacities and currents of your lights/batteries, it's impossible to make any calculations, but in general (suppose all other things equal) the amount of energy in one 4-cell battery should be the same as in another 4-cell one, regardless of internal connections.

    To put it simple: 100 watt bulb made for American market shines as bright as 100 watt bulb made for British market - the fact that both currents & voltages are different, doesn't change power equation.
  • diy
    diy Posts: 6,473
    -Archie- wrote:

    To put it simple: 100 watt bulb made for American market shines as bright as 100 watt bulb made for British market - the fact that both currents & voltages are different, doesn't change power equation.

    This. 4v is better IMO, as it simplifies the design though. Personally I think someone would be on to something if they created a pack with multiple outputs and voltage options, with removable cells.

    something like this is getting close:
    http://www.suntekstore.co.uk/product-14 ... aptop.html
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  • Ouija
    Ouija Posts: 1,386
    -Archie- wrote:
    , in previous post you were talking about reducing the number of batteries by half, but now - about rearranging the same quantity in different way, so it's a bit difficult to follow your idea...

    Not really hard to understand. One 18650 will run a 4.2v torch for an 1.5 hrs, two 18650 batteries (wired in series) would be required to run a 8.4v torch for the same amount of time. So, essentially, a 4.2v torch light requires half as many batteries to run a fixed period of time than a 8.4v torch?

    So four 18650's wired in a parallel pack and attached to a 4.2v torch would yield the same runtime as eight 18650's (4S/4P) powering a 8.4v torch. In other words, twice as many batteries for the same run time.
  • -Archie-
    -Archie- Posts: 152
    Ouija wrote:
    Not really hard to understand. One 18650 will run a 4.2v torch for an 1.5 hrs, two 18650 batteries (wired in series) would be required to run a 8.4v torch for the same amount of time. So, essentially, a 4.2v torch light requires half as many batteries to run a fixed period of time than a 8.4v torch?

    So four 18650's wired in a parallel pack and attached to a 4.2v torch would yield the same runtime as eight 18650's (4S/4P) powering a 8.4v torch. In other words, twice as many batteries for the same run time.
    I'm starting to wonder whether you're kidding or refuse to take anything except voltage in your calculations for reason, but last time:

    What torches? On what current? There is a plenty of torches designed to be powered by single or two cells (extension tube is included), and of course runtime with two cells is doubled if compared to single-cell mode.

    As for 4s4p battery, you can't use it to power 8.4v-only light, because 16.8 volt will simply kill it.
  • diy
    diy Posts: 6,473
    There are 3 parts to the calculation. Watts, Volts and Amps.

    At 1000 Lumen an XM-L is consuming around 10 watts.

    At 4.2v that requires a current of just under 2.4A at 8.4v it requires a current 1.2A So 4 * 2.4Ah cells will give the same run time (pretty much) when driving an X-ML to 1000. At 4.2v in needs 2.4A at 8.4v it needs 1.2A given the same run time either way.

    So for example a "standard" magic shine (SSC P7) runs at 8.4v and 1.3A when fully charged giving around 11W which is about right. Its the driver which is taking the input volts and stepping it up/down to achieve the desired current for the LED to consume 10W

    Edit: Just been mucking about with some old MCE emmitters that I had which ran at pretty low Amps. Just ran 8v and got 4.5A through giving probably about a 1000 real lumens. Sadly the LED died after 10 mins, despite my attempt at cooling. :D I read that the XM-L can take 5A with the proper cooling, but it appears an MC-E K bin cannot. I knew it was game over when it went blue,
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  • itguy2
    itguy2 Posts: 88
    Hi everyone

    I'm just about to order my first ever 501b XML t6 and have read this thread cover to cover!

    I have heard that the orange peel reflector gives more flood than the normal mirror reflector, but has anyone got any side by side photos?

    As the majority of my commute is street lit (only about 10 mins in actual darkness), I'm thinking that I'll only get one 501b - is there a reason most people buy two??

    I'm trying to keep costs down but need it quickly so have been looking at this eBay package http://www.ebay.co.uk/itm/CREE-T6-1000- ... 0722845166

    Any thoughts??
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  • diy
    diy Posts: 6,473
    Two allows you to run them on low and get longer run times, it also gives you a backup. They cost 7 quid so it's not a lot when you think about it. Even with the orange peel reflector they are not floods by any means. It just takes the sharpness off the light
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  • bartimaeus
    bartimaeus Posts: 1,812
    itguy2 wrote:
    is there a reason most people buy two??
    Because when you are mountain biking you really need a head torch as well as a bar torch... and as in diving it's worth investing in 'redundancy' in case something fails at an inconvenient time. And, of course, you can never have too much light :D .

    As DIY says an extra torch is not exactly a huge expense once you have a charger and some cells. For road use a single XML on medium is good for 3+ hours, but a second on your bars or as a spare in your pack is £7 insurance policy. I carry spare rear lights as well as they cost about £1.50 each (though the AAs I have are more expensive than the lights they are in!).
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  • Ouija
    Ouija Posts: 1,386
    -Archie- wrote:
    As for 4s4p battery, you can't use it to power 8.4v-only light, because 16.8 volt will simply kill it.

    Whoops! Should or read 2S/4P.

    itguy2 wrote:
    is there a reason most people buy two??

    Symmetry...... (wouldn't want to fall over with all that weight on one side of the bar ;) ).
  • inkz
    inkz Posts: 123
    I tend to aim one torch slightly ahead of the other to light up more road, two deffo better than one.

    Oh yeah, and looks badass.
  • apreading
    apreading Posts: 4,535
    If you only have one light and it fails or battery runs out then you have no lights to find your way back home...

    Best to always have two!
  • Dimme
    Dimme Posts: 5
    For some reason sometimes my battery runs out of power after 1 hour, the other time it burns for over 3 hours.

    Tried to find out what was causing this but couldn't find any explenation. Somebody has any idea?
  • Ouija
    Ouija Posts: 1,386
    Dimme wrote:
    For some reason sometimes my battery runs out of power after 1 hour, the other time it burns for over 3 hours.

    Tried to find out what was causing this but couldn't find any explenation. Somebody has any idea?

    Depends. What mode do you run the light in (high usually lasts for 1 to 1.5 hrs, medium for 2/3 hrs). The difference in brightness between high and medium can be quite small on some torches, significantly altering run times, which is why a lot of people with those torches use medium.

    Could also be down to temperature. Batteries work better when cooler. But then again, torches tend to draw more power when cool and power down to a lower setting when hot.

    Could be that your charger is cutting power to the battery too early, thinking that it's fully charged sometimes when it isn't. Switch the charger off, remove and reinstall the battery and then flick the charger back on and look to see if it continues to charge. If it doesn't after a couple of tries then the battery probably is charged and it's some other problem.
  • alibabameister
    alibabameister Posts: 100
    hi.
    the battery pack on my light is reading zero volts, if the batteries were protected and the voltage had dropped too low would the protected batteries give me the indication that there was zero voltage in them ? The charger is burnt out and I am awaiting a replacement but don't want to damage the new charger.
  • diy
    diy Posts: 6,473
    Protection circuit has tripped or failed, which breaks the circuit giving zero volts. Even totally dead packs will give some voltage
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  • alibabameister
    alibabameister Posts: 100
    diy wrote:
    Protection circuit has tripped or failed, which breaks the circuit giving zero volts. Even totally dead packs will give some voltage

    so it should come back when recharged ? the charger initially showed a red light then after an hour went green. the light stayed on for about 15 minutes then went straight off . upon further inspection the insides of the charger where rather charred
  • smashed
    smashed Posts: 100
    Apologies - definitely not a biking question but I thought this would be a good shout for decent advice...

    I need to buy a torch for up the stables - finding a horse in a big field in the dark is not easy.

    Looking for bright, with some flood as well as beam..together with rechargeable batteries (being able to get cheap spare batterys for backup would be even better).
    £20 max I would say...But the cheaper the better..
    Any ideas please? Been looking on Ebay but I don't want to waste my money on a Q5 or something that may not be up to it?

    Thanks
  • concorde
    concorde Posts: 1,008
    So any light that is XM-L T6 and advertised as giving out 1200 Lumens or 1800 Lumens... is basically impossible? As they can only give out more like a 1000 Lumens?

    Is that correct?
  • supersonic
    supersonic Posts: 82,708
    Yep (for a single LED). It may be possible with massive currents, if the conditions are right, but at the currents these use it is impossible. Even Cree's data sheet shows the max to be about 1000 lumens. As much as I like these lights, the claims should be cracked down on.
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  • concorde
    concorde Posts: 1,008
    Trying to recommend some to a few mates and they're being recommended 1600 lumen ones by others and it's getting pretty boring telling them that this is impossible! Just thought I'd check!

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