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  1. #1
    Fat on Willand Pond
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    New question here. USB Port 1800lm CREE XML-T6 LED Bike - Need Power?

    I just received this headlamp from China off Ebay and was looking to get the best - lightest - most powerful power source to plug into. All this light has is a standard USB 3 foot cable and came without any power source. I was told that any power bank should work but was looking for suggestions. Please let me know what might work best. Also, just need the light to go for 1-2 hours on a single ride from the power source. Please advise.

    USB Port 1800lm CREE XML-T6 LED Bike

    Features:

    100% Brand New and High Quality.
    Specially designed with USB power port(5V),
    Perfect to be used with power bank (not included) so that you can totally get rid of the cumbersome battery carrying.
    CREE XML-T6 LED, maximum lumen up to 1800LM, ultra bright.
    Three Modes: High/Low/Strobe(by pressing the button).
    Durable aluminum alloy crust, abrasion resistance.
    Water resistant, can be used in rainy weather(but can not put it into water) .
    Equipped with rubber rings for easy installation.
    LED indicators.
    Suitable for cycling, climbing, fishing, hunting, camping and other outdoor activities.
    Specifications:
    Item Type: Bicycle light
    LED: CREE XML-T6
    LED Quantity: 1pcs
    Port: 1 x USB 2.0 male
    Working Voltage: 5V
    Working Currant: 2A
    Modes:
    High: 2000MA (Current)
    Low: 1500MA (Current)
    Strobe: 2000MA (Current)
    Lifespan: Approx. 100000 hrs
    Housing: Aluminum alloy
    Color: Black & silver
    USB Cable Length: Approx. 95cm
    Light Size: 5.3 cm x 4.3 cm(L x D)
    15 Moto Night Train
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  2. #2
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    never heard of that before. Getting rid of the "cumbersome battery carrying" seems a bit pointless when the light doesn't work without it. Then it becomes "cumbersome dead weight carrying".

    If you need a plug and play solution, there are stacks of 18650 powered battery banks/ power packs on Fasttech and eBay, both prebuilt units and empty shells that you can put your own cells into. Usually they're either 2 or 4 cells - more cells = longer runtime but more weight (generalising).

    Personally, I'd drop the gimmicky USB connection (unlikely to be either waterproof or all that secure) and wire in a proper sealed cable to use with a proper sealed 3.7V battery pack.

    A link to the light you bought would be useful too

  3. #3
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    I saw this type of light before and wondered why anyone would buy them.

    Here's a link to the same style of light
    $16.33 POLAR Cree XM-L U2 3-Mode 900-Lumen 6500K Bike Light / Headlamp - 10W / USB powered at FastTech - Worldwide Free Shipping

    At least it's cheap.

  4. #4
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    Quote Originally Posted by mattthemuppet View Post
    never heard of that before. Getting rid of the "cumbersome battery carrying" seems a bit pointless when the light doesn't work without it. Then it becomes "cumbersome dead weight carrying".

    If you need a plug and play solution, there are stacks of 18650 powered battery banks/ power packs on Fasttech and eBay, both prebuilt units and empty shells that you can put your own cells into. Usually they're either 2 or 4 cells - more cells = longer runtime but more weight (generalising).

    Personally, I'd drop the gimmicky USB connection (unlikely to be either waterproof or all that secure) and wire in a proper sealed cable to use with a proper sealed 3.7V battery pack.

    A link to the light you bought would be useful too
    well I guess that the target of this light is quite small, personally I already own a verbatim 10'000 mah power bank, very light, I keep it in the bike saddle and I can connect 2 usb devices (probably more if I get a usb hub), I don't need the light on a daily basis since I don't use the bike to commute, it's a leisure road bike, hence the reason why a cheap light is enough, it's currently sold at around 13.50-16.00 USD with free shipping.
    The main thing I'm worried about is the waterproofness of the light, I'm pretty sure it's quite poor.
    But I guess that for 13 bucks I can't complain, the only way of getting a proper waterproof light is going for the brand names like knog, niterider, but that would set you back of at least 50 bucks.

  5. #5
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    Quote Originally Posted by varider View Post
    I saw this type of light before and wondered why anyone would buy them.
    I see many advanteges.

    I had one 30$ chinese bike light with battery, and the light part was good, but the battery looked quite cheap and low quality, and worked for just half a year. So I bought new USB light for 15$ and good and powerful powerbank for 60$. This way I have excellent waterproof powerbank that will last much longer than the first battery, and excellent capacity of cca 5 hours on the highest (1000 lumen) level or even longer on lower one. Also, I can simple add cheap aditional USB cord and place this powerbank in a bag below my seat.

    Also, if the market offers better USB light (for example some flood light), I will be able to buy it without need for a new battery.

  6. #6
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    How many amps can a power bank deliver via the USB connection? USB is usually limited to about 1 amp IIRC. If that is the case with the powerbank then you are limited to ~5 Watt lights.
    GoPro adapters for bike lights http://www.pacifier.com/~kevinb/index.html

  7. #7
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    This light doesn't work if output is below 2A, I guess that is the answer to your question?

    This particular light is strong enough, but the main beam is very narrow, but I'll buy better one if it shows up on the market...

  8. #8
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    Quote Originally Posted by bbsantic View Post
    This light doesn't work if output is below 2A, I guess that is the answer to your question?

    This particular light is strong enough, but the main beam is very narrow, but I'll buy better one if it shows up on the market...
    Hi, Im interested in a similar setup. I'm trying to find a light that is compatible with my powerbank and needs. What confuses me are the same LEDs being marketed at different lumen values (I'm guessing this is mostly because of the battery source?)

    The power bank I have has a (default 5v) max current of 4 amps per usb, and has a 12Ah capacity. Which light do you think would work with my battery pack? You mentioned it needs to be over 2a, would setting a light to max brightness cause damage to it when using a 4a max "smart battery pack"

    Im under the impression night riding requires a handlebar light and helmet light regardless of lumens. If i can get away with a single helmet mounted light/s that connects to a power bank in my hydration pack that would be ideal.

  9. #9
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    I think battery packs from departments stores can power 5w lights for a short time, the full speed tablet chargers can power 10-15W bulbs and the pack I have can power 20W bulb. I just don't know what the light/head lamp options are for usb powered 10W+ bulb/s and how long they would last
    Last edited by jokaankit; 12-28-2014 at 10:45 PM. Reason: mistake

  10. #10
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    Quote Originally Posted by jokaankit View Post
    Im under the impression night riding requires a handlebar light and helmet light regardless of lumens. If i can get away with a single helmet mounted light/s that connects to a power bank in my hydration pack that would be ideal.
    Most people prefer a spot on the helmet and a flood on the bars. A light on the bars will give you shadows to help you see the terrain while a spot on the helmet lets you see what is coming up & around corners.

    Either way you should have two independent lights & batteries - you do not want to be stuck in the boonies with no light
    Quote Originally Posted by jokaankit View Post
    What confuses me are the same LEDs being marketed at different lumen values (I'm guessing this is mostly because of the battery source?)
    No, it is mostly BS. Lumens should be measured, but that is expensive so sellers either (1) quote manufacturer figures, which are in ideal conditions and never replicated in practice or (2) think of a number & double it.
    Quote Originally Posted by jokaankit View Post
    The power bank I have has a (default 5v) max current of 4 amps per usb, and has a 12Ah capacity. Which light do you think would work with my battery pack? You mentioned it needs to be over 2a, would setting a light to max brightness cause damage to it when using a 4a max "smart battery pack"
    It will be fine - the driver in the light limits the current supplied.

    My personal opinion is that a usb powerbank is a poor choice for a light - it needs a boost converter to get the voltage to 5v & then a boost or buck converter to supply the voltage required for the light. An excellent converter is ~85% efficient, so 2 means ~72% efficiency. 70% efficiency is more likely so you are down to 49% efficiency.

    I suggest you wander over to the Lights and Night Riding forum and look at your other options. This looks like a promising option for a bar light

  11. #11
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    I picked up the duo package for the bar. I'm still considering using this light for my helmet. I'm a bit confused on how you arrived to 50%. Is the drop from 70% to 50% from the driver inefficiency? I see what you are saying about it being foolish to use, considering it would last for only 30 minutes on high if your approximation is close. I think the pack could be waterproofed. If it helps this bank can charge a 7000mAh ipad battery from dead to full while using the ipad at full brightness the entire 1 hour charge time. Thanks Bruce.

  12. #12
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    USB Port 1800lm CREE XML-T6 LED Bike - Need Power?

    Not foolish, just inefficient. All I was trying to demonstrate was how multiple drivers decrease efficiency ie 0.7 * 0.7 = 0.49

    The main reasons for caring about efficiency are run time & dissipating the heat

  13. #13
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    the pack has 4 ICR18650-30B Samsung SDI 2DB1. configured 2s2p. I might look into chargers and a box. Thanks bruce

  14. #14
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    Some of these cheapo ebay lights look like an amazing start for a DIY project!

    5000 Lumens 2X CREE XM L U2 LED Cycling Bike Bicycle Light Headlamp Headlight | eBay

    Sure all the specs are fake/misleading... but 2 XML's and an aluminum housing for 23 bucks is a steal.

    The 18650 pack might suck, but I have extras laying around. I can heat sink that thing properly, toss in a 3 amp driver and have something close to ~1800 lumen. Not bad!

  15. #15
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    If anyones interested, i got that light. Im going to guess its under 1k lumen. Looks like 500ish. Leds are mounted on a peanut shaped pcb instead of stars. Driver is cheesy and not constant current.

    The housing is pretty good though. Its great for 23 shipped.

  16. #16
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    Does the housing have a solid surface for the emitter plate to sit on or is it just supported by a small ledge around the edge?
    GoPro adapters for bike lights http://www.pacifier.com/~kevinb/index.html

  17. #17
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    A small ledge. Its not suitable to be overdriven as-is. However, theres plenty of room to stuff a 1/8th inch alu plate in there for a decent heat sink.

  18. #18
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    Ya solarstorm x2. If you know your way around the drivers and some aluminum you can modify for optics and boost it a bit. I have the x3 which with a bit of a output boost, new plate to hold copper pcbs and optics, its a really nice light.

    These little heads wont handle 3A true very well that ive found so far. im only running 2A with noctigons in my x3, and added a custom heat sink gopro mount from vancbiker to keep it able to handle the power and heat from it. Wonder if that x2 can take it a bit better cause my yindings etc with the heat sink gopro mounts can only handle 2.5A max and get pretty hot on high.
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  19. #19
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    Quote Originally Posted by One Pivot View Post
    A small ledge. Its not suitable to be overdriven as-is. However, theres plenty of room to stuff a 1/8th inch alu plate in there for a decent heat sink.
    Or a 20mm copper end cap from your local plumbing supplier. Tigris is right about heat dissipation though.

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