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  1. #1
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    bt21 and MJ808 failed. I got $150 and need two lights. what to get?

    I got a bt21 last year and it already only lasts 1 hour, it over heats I guess. Same for a brand new magic shine MJ808 it only lasted an hour and it sometimes doesn't even turn on. Last week I got stranded on the trail after BOTH lights failed and I had to walk out in the dark.

    I tried to read through these forums to determine what a good cheap light is I get totally lost because it is so technical.

    I just want two plug and play lights that work, one helmet, one bar and I can spend $150. What should I get?

    Also, are the head units likely OK and I just have bad batteries? If so what are some good batteries to get? Do I need a new charger?

    I haven't really used the bT21 more than 15 times. The magic shine was its second use, it didn't even turn on the first time I tried to ride.

    Quick shipping and available on amazon or ebay are a plus IMO.

  2. #2
    RAKC Industries
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    Problem is for $150 your not going to get any better of a set of lights than you already have. Ya they'll work but same risk of failure.

    Magicshine shouldn't be DOA though.

    Batteries are Universal between those lights (as they are with most lights) so you can simply check the battery packs by charging and sealing between lights.

    Chances are the bt21 battery pack is toast. If you stored the pack dead then it's definitely trash. Without proper equipment to test and repair if possible yourself.

    If it was me I would check the batteries by swapping them after charging. See what light works and if you have a decent battery pack to go with it out of what you have.

    Then take your $150 and by a better light. And don't get stuck on eBay or Amazon, you pay more for stuff that way many times. Just buy from reputable companies and all is good.

    Sent from my XT1565 using Tapatalk
    Life on a bike doesn't begin till the sun goes down.

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  3. #3
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    Idea!

    This is a great bar light!
    http://www.kaidomain.com/p/S026105.K...ke-Light-Black

    Quality batteries:
    http://www.kaidomain.com/p/S024442.K...n-Battery-Pack
    http://www.kaidomain.com/p/S024443.K...n-Battery-Pack
    You can use your old charger.

    I don't fancy helmet light but maybe this one will work?
    http://www.kaidomain.com/p/S026169.B...ke-Light-Black

    Unfortunately Chinese New Year can make delivery times somewhat longer.


    Peace!
    Last edited by Stark; 02-23-2017 at 03:33 PM.

  4. #4
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    With any of the cheap Chinese lights you can improve the chances that it will work for a long time.

    Open it up and repair the sketchy solder joints.

    Apply thermal paste to the heat path mating surfaces.

    Seal any obvious water entry points.

    Use batteries from reputable sources.
    GoPro adapters for bike lights http://www.pacifier.com/~kevinb/index.html

  5. #5
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    Where did you get the batteries?

    You said it was a brand new magicshine? Those come with warranties, depending on where you bought them.

    It's hard to imagine both lights failing on the same ride.

  6. #6
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    Quote Originally Posted by BigBo View Post
    I got a bt21 last year and it already only lasts 1 hour, it over heats I guess. Same for a brand new magic shine MJ808 it only lasted an hour and it sometimes doesn't even turn on. Last week I got stranded on the trail after BOTH lights failed and I had to walk out in the dark.
    What ambient temperature was during that incident, and what batteries you're using?

    I use MJ-808 for many years, and my cycling mates are using both MJ-808 and BT-21 without any troubles, so I'm really surprised...

  7. #7
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    I'm using these 2 on bar and helmet. Right within your price range. Nothing wrong with buying from Amazon.

    https://www.amazon.com/ITUO-flashlig...rds=ituo+wiz20

    https://www.amazon.com/CatEye-Volt-3...ateye+volt+300

  8. #8
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    Batteries came with the lights.

    It was actually a new MJ-900 the kind with the orange highlights from action led i think. I can't find a record of purchase.

    Temp was 50 degrees. Maybe the battery is shot as mentioned, it was stored dead for a long time.

    Maybe the ITUO Wiz-XP3 is a good option?

  9. #9
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    I would try to check the BT21 on another battery that it seems ok and then purchase a quality pack built with Panasonic cells - I'd choose the 4-cell from Kaidomain linked above.

    As far as the MagicShine - try contacting Action LED and see what Jim will do to help you out.

    As far as another inexpensive light (bar light use) - you could go with the Revtronic (Nitefighter) BT40S full kit from Amazon. The seemed to have cheapened the battery pack (cheaper unknown cells now), but it should at least be decent. Or you can buy the head only from Amazon and pickup another Panasonic cell pack. The BT40S has seemed to have held up pretty well, though some claim it's not bright enough / too floody.

    -Garry

  10. #10
    RAKC Industries
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    If you stored the batteries dead for a long period their done. You can't store lithium batteries dead, it kills them.

    You mentioned the XP3 by that is a little over budget ($200 or $210 on Amazon). If you wanted to go that high it would overpower the lights you currently have.

    XP2 is $150 (right in your budget) and would be a good companion light and something that is reliable if one of your other lights fail again.

    XP3 is the same, I've loaned out my xp2 off my bars to friends because their cheap Chinese stuff fails. I've done entire 2 hour rides with just a single XP3 on my helmet. Was group rides though. I never go out alone with one light.

    Sent from my XT1565 using Tapatalk
    Life on a bike doesn't begin till the sun goes down.

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  11. #11
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    Yeah, I think you may have just killed your batteries. I recommend getting some new ones from action led and maybe a new charger as well. $60 to $70 and you are back on the trail.

  12. #12
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    Quote Originally Posted by garrybunk View Post
    As far as another inexpensive light (bar light use) - you could go with the Revtronic (Nitefighter) BT40S full kit from Amazon. The seemed to have cheapened the battery pack (cheaper unknown cells now), but it should at least be decent. Or you can buy the head only from Amazon and pickup another Panasonic cell pack. The BT40S has seemed to have held up pretty well, though some claim it's not bright enough / too floody.

    -Garry
    That's nice to know. I was wondering why they seemed to have removed the BAK part from the 5200mah ad part.

  13. #13
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    Quote Originally Posted by Staypuft1652 View Post
    That's nice to know. I was wondering why they seemed to have removed the BAK part from the 5200mah ad part.
    Ledoman posted that info a little while ago; I have no proof myself. I've not heard any more about the "new pack" specifically if Ledoman ever did any testing on it. Problem is they may test "decent" while new and then quickly go downhill.

    -Garry

  14. #14
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    Quote Originally Posted by garrybunk View Post
    Ledoman posted that info a little while ago; I have no proof myself. I've not heard any more about the "new pack" specifically if Ledoman ever did any testing on it. Problem is they may test "decent" while new and then quickly go downhill.

    -Garry
    I hadn't seen that so I appreciate you pointing it out.

  15. #15
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    AFAIK they (Revtronic) are about to return to BAK cells. The last cells used were bit uneven in quality. At least with the pack tested I've experienced some voltage difference between cells in series. On first two discharges the capacity was about 5200mAh at 2A load, though. Since I've passed pack to other user I can't say how it behaves after many cycles. It might get unbalanced soon.

  16. #16
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    Quote Originally Posted by ledoman View Post
    AFAIK they (Revtronic) are about to return to BAK cells. The last cells used were bit uneven in quality. At least with the pack tested I've experienced some voltage difference between cells in series. On first two discharges the capacity was about 5200mAh at 2A load, though. Since I've passed pack to other user I can't say how it behaves after many cycles. It might get unbalanced soon.
    Thank you ledoman.

  17. #17
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    Unbalanced cells might be one of the reasons you are having problems. Measuring voltage of the pack right after full charge would tell that. If you have any chance to do that with some voltmeter (DMM) or have a friend who can do it I would suggest it. We might help you more with that info provided.

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