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  1. #1
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    Paging MagicShine Experts

    Hi, Magicshine shuts off after 30 minutes. Battery voltage level is 0.0 at cutoff.

    Battery level at full charge is 7.54 volts according to my voltmeter. Charger output looks good at standard 8.4. Bad battery or pcb ?

    When plugging in the head, the light stays on and does not do the blink on then back off as is standard for this light.
    Could that also be due to low voltage level of 7.5 on the battery at full charge when I plug in the lighthead , or an additional problem with the circuit in the lighthead ?

    Thanks guys.

    Edit:

    PS Geo immediately addressed issues I had (prior to my tech research here) and is the first place to shop for this great light imho. In the past I only wish I would have had this kinda service turn-around from the big light makers.
    Last edited by glovemtb; 02-27-2010 at 08:08 PM.

  2. #2
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    Quote Originally Posted by glovemtb
    ...When plugging in the head, the light stays on and does not do the blink on then back off as is standard for this light.
    Could that also be due to low voltage level of 7.5 on the battery at full charge when I plug in the lighthead , or an additional problem with the circuit in the lighthead ?

    Thanks guys.
    The normal operation is for the light to stay on when you plug it in. Yours in acting normal in this respect.

    Is this a new light or one you have been using for a while?

    I'd give it a full 4 hr+ charge and see how it does.

  3. #3
    GeoMan
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    Quote Originally Posted by gmcttr
    The normal operation is for the light to stay on when you plug it in. Yours in acting normal in this respect.

    Is this a new light or one you have been using for a while?

    I'd give it a full 4 hr+ charge and see how it does.
    Agreed.

    Geo
    GeoMan
    We Ride!
    www.geomangear.com

  4. #4
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    The normal operation is for the light to stay on when you plug it in. Yours in acting normal in this respect.
    Is this a new light or one you have been using for a while?
    I'd give it a full 4 hr+ charge and see how it does.
    Thanks, gmcttr
    New light and battery. Geo is allready working on getting things right for me. I am just trying to figure out my new (easily best bang for the buck light.)
    Ok, I thought proper operation was for light to flash when plugged into battery but go back off. That happens about every third of fourth time when I plug it in.
    Agreed.
    Geo
    Thanks Geo,
    I will try cycling (sorry pun) it but the only thing is after plugging in for a charge a very short time later the green diode on charger goes on to show full charge.
    I assumed that at green the voltage is shut off from the charger or the pcb. Again, at 7.54 volts across the battery the charger shows green.
    Thanks, I did not realize li-ions needed the cycling to come up to full charge.
    From what I had read this particular battery should give about 2 hours out of it the first ride or so, then should give the full 3-3.5 hours after that at high.
    I will cycle it several more times and leave it plugged in overnight again and see how it goes. Again, charger goes green after ~~30 minutes plugged in even though battery was at 0 volts after discharge.
    Edit:
    Sure sounds like I am wasting my time here with a bad battery. But new to this line so and just trying to figure things out. Not sure but from reading below analysis sounds like it has deep discharged from manu(otherwise why would I be getting zero volts across battery after light head has turned off) and now pcb will not allow it back up to full charge.
    "In spite of these preventive measures, over-discharge does occur. ....Extreme low voltage must also be prevented. The safety circuit is designed to cut off the current path if the battery is inadvertently discharged below 2.50V/cell. At this voltage, most circuits render the battery unserviceable and a recharge on a regular charger is not possible....."
    http://www.batteryuniversity.com/partone-12.htm
    I guess at this point I will just leave plugged in a fire proof pot overnight again and see what cooks.
    Last edited by glovemtb; 02-27-2010 at 07:21 AM.

  5. #5
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    Cycling never improves the capacity of Li-ion batteries themselves. In some intelligent battery packs, it can serve to "recalibrate" the upper and lower limits of the fuel gauge circuit in the pack. The magicshine pack does not include a fuel gauge circuit built into the pack, so that doesn't apply in this case. Leaving the pack on the charger for a long time can improve the balance of a badly out of balance pack to some extent, but even if you get such a pack to work better in the short term, it'll have problems down the road.

    The 0V reading on your pack after discharge indicates that the protection PCB is shutting the pack down. This is mostly likely caused by a badly balanced pack. The batteries aren't at 0V internally, but one of the two banks of cells is dropping down to the 2.5V limit and the protection PCB is shutting down current flow out of the pack, hence 0V output. This is also supported by the 7.4V reading on full charge. What's likely happening on charge is one of the banks is hitting the 4.35v upper limit and the protection PCB is shutting down the charge current because of the upper limit. When that happens the charger light will turn green. One bank is likely at 4.35V and the other is at 3.05V and the pack output will be 7.4V

  6. #6
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    Quote Originally Posted by glovemtb
    ...Ok, I thought proper operation was for light to flash when plugged into battery but go back off. That happens about every third of fourth time when I plug it in.
    If you jiggle the connector as you plug it in, you make contact (turning the light on) and break contact (turning the light off). The light stays off when this happens rapidly. You can intentionally make the light flash and stay off by double-tapping the connectors while plugging them in.

  7. #7
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    Quote Originally Posted by gmcttr
    If you jiggle the connector as you plug it in, you make contact (turning the light on) and break contact (turning the light off). The light stays off when this happens rapidly. You can intentionally make the light flash and stay off by double-tapping the connectors while plugging them in.
    Cool, thanks that make sense.

  8. #8
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    Quote Originally Posted by MtbMacgyver
    Cycling never improves the capacity of Li-ion batteries themselves. In some intelligent battery packs, it can serve to "recalibrate" the upper and lower limits of the fuel gauge circuit in the pack. The magicshine pack does not include a fuel gauge circuit built into the pack, so that doesn't apply in this case. Leaving the pack on the charger for a long time can improve the balance of a badly out of balance pack to some extent, but even if you get such a pack to work better in the short term, it'll have problems down the road.

    The 0V reading on your pack after discharge indicates that the protection PCB is shutting the pack down. This is mostly likely caused by a badly balanced pack. The batteries aren't at 0V internally, but one of the two banks of cells is dropping down to the 2.5V limit and the protection PCB is shutting down current flow out of the pack, hence 0V output. This is also supported by the 7.4V reading on full charge. What's likely happening on charge is one of the banks is hitting the 4.35v upper limit and the protection PCB is shutting down the charge current because of the upper limit. When that happens the charger light will turn green. One bank is likely at 4.35V and the other is at 3.05V and the pack output will be 7.4V
    Very nice, thanks for great analysis. Sounded like the PCB was shutting it down but I did not know why. I guess the trick is with li-ions (since you want longer term storage at a lower % of total capacity); to really charge it higher depending on how long you expect it to remain in inventory. Cause once a bank gets too low you have a light that won't take a charge without using a battery analyzer like the cadex. Or, sounds like I could separate them and run a tiny trickle charge form a dc variable power power supply (closely monitored) on the one that is truly low and get it up to snuff, rebuild and the regular power charger would work.

    Great MtbMacgyver, thanks for help with this. This is no reflection (ouch pun again) on this great light deal I am very happy with my purchase but am also very interested in the technology.
    Last edited by glovemtb; 02-27-2010 at 08:11 PM.

  9. #9
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    Quote Originally Posted by glovemtb
    Very nice, thanks for great analysis. Sounded like the PCB was shutting it down but I did not know why. I guess the trick is with li-ions (since you want longer term storage at a lower % of total capacity); to really charge it higher depending on how long you expect it to remain in inventory. Cause once a bank gets too low you have a light that won't take a charge without using a battery analyzer like the cadex. Or, sounds like I could separate them and run a tiny trickle charge form a dc variable power power supply (closely monitored) on the one that is truly low and get it up to snuff, rebuild and the regular power charger would work.
    When a new pack is badly out of balance, it usually indicates something is wrong with some of the cells such that they have greatly reduced capacity. It's not likely to just be an issue of getting them charged equally. Since the magicshine pack is 2s2p, this could also be caused by a connection issue with one of the parallel cells. So one bank may be 2 cells in parallel and the other bank may be a single cell and the fourth cell in the pack may be disconnected.

  10. #10
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    Thanks again Macgyver, enjoyed reading you diy light history and the thread about resistors in ms. (which is your favorite, duct tape or gorilla tape ? ).
    Last edited by glovemtb; 02-28-2010 at 07:13 AM.

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