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  1. #26
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    That's a nice charger if you run individual batteries....but most of use run premade packs....and that doesn't look like it will work.( or am I missing something?)

  2. #27
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    Yes. Only used for charging/monitoring individual cells.

  3. #28
    Action LED Lights
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    One thing I want to add to this, Never charge a Li-ion pack when the pack is below 30F. Doing so can cause shorts to develop in the pack. When you come in after that winter ride bring the pack inside and give it some time to warm up before plugging it in.
    Jim Harger
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  4. #29
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    After the first battery issue a couple of years ago, I had enough and built a dynamo front wheel to power my commuter lights. Now, I get plenty of (not blinding) light from 2 XMLs and a red XP-E, and all I ever have to do is turn em on and clean the lenses. (Oh, and ride my bike, which I enjoy even more, now that doing so also lights my way.) No batteries, chargers (in fire-proof bags?), range anxiety or noticeable drag from the hub. May I offer you some Koolaid?

  5. #30
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    Quote Originally Posted by jack in the matrix View Post
    May I offer you some Koolaid?
    No thanks!

  6. #31
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    Oops

    Just realized I left my cheap battery on the charger all last night and today. In my garage tho.

    Hope the house is not burned down when I get home.

    Geez, completely forgot.

  7. #32
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    Scary!

  8. #33
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    This makes all my light screw ups look minor.
    Thanks!
    DIY LED Bike Lights:
    A few Dynamo builds and some Small battery lights

  9. #34
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    Quote Originally Posted by mb323323 View Post
    Just realized I left my cheap battery on the charger all last night and today. In my garage tho.

    Hope the house is not burned down when I get home.

    Geez, completely forgot.
    A simple solution for this is to plug the chargers (if you have more than one) into a power strip and then plug that into a timer. You can have the timer shut off the power after 6 hours or something.

  10. #35
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    As sidenote, I've read of some occasional cases in german mountainbike forums, that bikelights imported from China/Hong Kong and the like, shipped via the common postal channel, were stopped and rejected to import at the german customs authority border. Expressely for "unsafety of the charger, not complying with the german (EC) standards".
    So at least it seems to be a known issue even in some customs agencies.

    Regards

  11. #36
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    Quote Originally Posted by CHnuschti View Post
    As sidenote, I've read of some occasional cases in german mountainbike forums, that bikelights imported from China/Hong Kong and the like, shipped via the common postal channel, were stopped and rejected to import at the german customs authority border. Expressely for "unsafety of the charger, not complying with the german (EC) standards".
    So at least it seems to be a known issue even in some customs agencies.

    Regards
    That almost sounds "Facist". I have the feeling there is likely quite a black market in Germany. At least where I live if I want to buy "cheap junk electronics", I'm free to do so as long as it doesn't hurt anyone else.

    Interestingly, no one stopped the Germans from exporting the first VWs into the United States back in the day. Need I say those first VW Beetles were pieces of crap ( yeah, I owned one ). Still, that didn't stop people from buying them because they were dirt cheap.

  12. #37
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    Well these heap packs have pretty bad recycled cells inside which are not in the same condition with varying capacity. The PCB does not prevent them from overcharge and does not see the balance lead when charging through the PCB with the charger that came with the light. I have tested this, as I got an unbalanced pack with the light. Two cells were topped to the 4.3V!!!! but the other two just sit at 8.4V - 4.3V = 4.1V. That was here probably the cause of the explosion - the unbalanced state. So it does not need to explode if you charge it with a balance charger skipping the PCB. The cells are likely unbalanced in most cheap lights, so be careful using them! Electrical knowledge is required when handling these lights - at least I think.

    Quote Originally Posted by Action LED Lights View Post
    One thing I want to add to this, Never charge a Li-ion pack when the pack is below 30F. Doing so can cause shorts to develop in the pack. When you come in after that winter ride bring the pack inside and give it some time to warm up before plugging it in.

  13. #38
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    Things like this is why I've never used original chargers supplied with lamps like this. I always balance charge my batteries using RC charger.
    I'm pretty sure MK96 is right, one group of batteries had less capacity than the other and it got severely overcharged. Btw, 4.3V isn't a problem even for a bad quality 18650, so imbalance must have been even greater, and then even high quality cell would go thermal.


    Quote Originally Posted by Action LED Lights View Post
    Never charge a Li-ion pack when the pack is below 30F. Doing so can cause shorts to develop in the pack.
    Not only it can cause shorts to develop, it also ruins battery capacity. After a few cold charges battery can have it's capacity considerably reduced.

  14. #39
    Action LED Lights
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    Quote Originally Posted by bobale View Post
    Things like this is why I've never used original chargers supplied with lamps like this. I always balance charge my batteries using RC charger.
    A properly design battery pack (like all the ones we sell) have a balancing circuit built into the PCB with a lead to the center connection. However, these PCB's, and all hobby chargers, treat parallel pairs as a single cell. Balancing is only for cells in series and does nothing for mismatched pairs.
    Jim Harger
    Action LED Lights
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  15. #40
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    That's why I've added balance connector to every multi-cell pack I have, so I can really balance them and monitor votages at cell level.

  16. #41
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    I'm sorry Jim, but with all due respect I strongly doubt that the PCB in your battery packs balance charge. Balance charge PCBs are characterised by large thick wires used to burn of dV between series wired cells and I have never, ever, seen this type of PCB used in bike battery packs whether from Chinese manufacturers or high end US and German lights. I've even looked into using them myself to avoid having to add balance taps to my batteries, but they're seriously expensive and bloody huge (e.g.http://www.batteryspace.com/pcmwithe...02s20-265.aspx)

    The lead to the center connection is for voltage monitoring individual parallel banks, nothing more, presumably with a trip voltage built into the PCB that, should, in theory, prevent such massive cell imbalance that results in fire/ explosion from overcharging.

    Parallel cells can never get out of balance as the voltage of individual cells in the parallel banks will "float" until termination voltage is reached. Similarly, on discharge, a cell with lower capacity that it's brothers in a parallel bank will simply stop contributing current once it's fully discharged.

    The BIG problem is series cells getting out of balance, as a result of differences either in capacity of the series cells or through different rates of self discharge. The PCBs in commercially available battery packs do nothing to prevent this imbalance as it is purely a function of the quality and matching of the cells at assembly. Balance charging with a balance tap will paper over the cracks of an unbalanced pack, but it won't treat the symptom of the problem, which is poor cell choice.

    Now, I'm not casting any aspersions with regard to the packs you sell as I have no experience of them and I'm sure that they're what you say they are. They do not, however, have balance PCBs.

  17. #42
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    Quote Originally Posted by mattthemuppet View Post
    .....The BIG problem is series cells getting out of balance, as a result of differences either in capacity of the series cells or through different rates of self discharge. The PCBs in commercially available battery packs do nothing to prevent this imbalance as it is purely a function of the quality and matching of the cells at assembly. Balance charging with a balance tap will paper over the cracks of an unbalanced pack, but it won't treat the symptom of the problem, which is poor cell choice....
    You can also use a " 4-cell holder" to get around this problem but then you have to remove the cells and charge each cell separately. I was doing this with one of my other lamps but soon found the ( cells in/ cells out ) routine quite tedious. So much easier to just plug the battery into a single charger.

    Sure would be nice if standard 4-cell 7.4 volt Li-ion bike batteries came with pre-setup balance leads ( like some of the Li-Po ). Now if they did you would need a much more expensive charger but that almost goes without saying.

  18. #43
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    Quote Originally Posted by Cat-man-do View Post

    Sure would be nice if standard 4-cell 7.4 volt Li-ion bike batteries came with pre-setup balance leads ( like some of the Li-Po ). Now if they did you would need a much more expensive charger but that almost goes without saying.
    It's not just the more expensive charger (although you can get 2S/3S mini balance chargers for not much), it's the issue of waterproofing an extra cable and plug. That's my biggest peeve and I think it would add a lot to the cost of the light, without really providing much benefit. For high quality batteries, balance charging isn't going to make a huge difference (general use and age will have far more significant effects); for cheap batteries, it's not going to affect the underlying problem of cheap cells, but at a cost that I doubt any of them would pick up.

  19. #44
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    Quote Originally Posted by spartacus001 View Post
    Xtar has just released their newest VP1 smart charger featuring a digital display of the charging status.

    VP1

    Attachment 769077
    Would it be tough to attach a lead to these to charge sealed battery packs? I've done this in the past with simple chargers.

    Any other suggestions for inexpensive but safe chargers?

    I use a good quality hobby charger but when I make light sets for friends I've been getting them cheapo chargers. Be nice to find something in the middle for them.

  20. #45
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    I think hobby charger is the best solution ;-) Perhaps some from hobby-king.

  21. #46
    Action LED Lights
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    Keep in mind, a hobby charger balances batteries in series but will do nothing for mis-matched cells in parallel.
    I agree with Cat that the best DIY solution would be individual protected cells in a battery holder. (I'm working on a source.)
    Jim Harger
    Action LED Lights
    www.action-led-lights.com

  22. #47
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    Quote Originally Posted by Action LED Lights View Post
    Keep in mind, a hobby charger balances batteries in series but will do nothing for mis-matched cells in parallel.
    I agree with Cat that the best DIY solution would be individual protected cells in a battery holder. (I'm working on a source.)
    A nice 8.4V battery case like this would be great.

  23. #48
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    WOW, scary being I just got mine in the mail today

    Ok so I ordered one of these lights came in today. Didnt realize the companies were selling possibly already soft shorted cells.....

    But luckily for me I preplanned (cause the wall chargers for and Li based batteries are asking for problems) to take the cord off the charger and plug into my smart charger.



    One of the few things I have left from my RC days. Kept it cause it charges ANY rechargeable battery I have, even for my cordless drill and so on. Now even happier I still have it cause I can safely charge these. I do have to say for hte money you cant go wrong on these lights, especially if your like me and a DIY type person with alot of knowledge on building battery packs and LED light systems. $27 for a light I can mod the hell outta with new pack for less than another $50 and will be comparable to high end $200+ lights
    Trek Marlin 29er

    Like It, Love It, Want Some More Of It!

  24. #49
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    Quote Originally Posted by tigris99 View Post
    $27 for a light I can mod the hell outta with new pack for less than another $50 and will be comparable to high end $200+ lights
    Should plan on at least looking at the driver and assembly care too. The cheapo lights typically some components that are under-spec'd on the driver. Poor soldering is common. If it has a buck style driver, check that the inductor is glued to the board. Poor heat path/no thermal transfer compound. Fun stuff for a DIY type person though.

  25. #50
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    ya that was what I was referring to as mod the hell outta lol. New driver, LED, and cells for the pack. So $27 for a housing, pouch, switch (which I like cause its lit) and long as wires with connectors already. As well as battery monitor possibly. Dont know much about drivers yet learning that atm so thnx for the pointers about that, things to check!!!
    Trek Marlin 29er

    Like It, Love It, Want Some More Of It!

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