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Old 12-31-09, 05:38 PM   #1
AdamDZ 
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MagicShine connection problem not connector related but deffective circuit board?

So after having some wet weather related problems, I sealed the battery with liquid tape, extended the cable and put the battery in my waterproof pannier. It worked fine for couple of weeks. In the last few days the connection become intermittent. I would unplug it and plug it back and it would work for a bit. Today, it stopped working completely. When I plug the light in it just blinks and dies, no light, no LED. It seems like connector problem, but it is not.

I took the battery apart. There is a small circuit board attached to it and that circuit board is the problem, not the connector. I un-soldered the cable from the circuit board, cut off the connector from the light and connected bare wires from the light directly to the circuit board output where the wire was soldered: the same thing, the problem persists. If I connect the wires directly to the battery output, bypassing the circuit board, it works fine. Also, if I connect the light to a 6V power supply it works fine, so the light is OK.

So I wonder if there is any way to obtain that circuit board, I believe it's needed for charging. Otherwise, I'll just get another battery, but not the same. Has anyone found a reliable battery replacement? It can be larger, that's OK and obviously I don't mind soldering the connectors. I've found many on the net but I'd like to know if anyone actually has a good working alternative that was tested under normal use.

Edit: To clarify: both the battery directly and the circuit board provide stable ~8.3V without load, when the only thing connected is the multimeter. The problem lies in the circuit board failing under load. If I connect the light, while the multimeter is connected at the same time it shows that the voltage instantly drops to ~2V the moment the light is connected.

The battery that comes with MagicShine is 4000mAh, 7.4V rated at 1.5A. I believe the light will work with any battery that supplies 6V to 8.4V and can deliver 1.5A. However, 7.4V is recommended.

Happy New Year everyone!

Adam

Last edited by AdamDZ; 12-31-09 at 06:08 PM.
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Old 12-31-09, 06:43 PM   #2
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Answering my own post I wonder if this would work:

http://www.batteryjunction.com/pcbfor7li181.html

***

So actually, I think this is how to build your own MagicShine battery that will work with the existing charger. You won't be saving a lot of money, but you will have options to build a larger capacity battery and the satisfaction of DIY

Anyone with more electrical knowledge please let me know if this makes sense.

These are the type of cells used in MagicShine battery, 3.7V Lithium-Ion 18650:

http://www.batteryjunction.com/lg-18650-2600.html

Except that these are 2600mAh and those used in MagicShine battery are 2000mAh.

Get 4 or even 6 or 8. Solder them in series in pairs to get 2, 3 or 4 pairs that will produce 7.4V each. Then solder those pairs in parallel. That will give you anywhere from ~5200mAh to whooping ~10400mAh with 8 batteries. Keep in mind that original battery is 4000mAh.

Of course, charging will take more time. But imagine: you can get a second lighthead from Geoman for $45. With two lights and 8 cells you should still get ~3.5h runtime, if my math is correct... One light with 8 cells would give you ~7h runtime.

There are some extra design possibilities when DYI, for example you can arrange your cells flat, make a long flat 8-cell battery, so it will fit in the back pocket of your cycling jersey or jacket or Camelbak. Or you can build a small 2-cell battery for quick rides with 2600mAh capacity (close to 2h runtime) if you want to go light on gear.

Add the protection PCB:

http://www.batteryjunction.com/pcbfor7li181.html

Use your imagination: put them in a plastic box or bottle. I'd just wrap them in plastic foil, then electricians tape and cover the whole thing in liquid tape.

Check this out for waterproof connectors, they even have handlebar mounted switches:

http://www.batteryspace.com/water-pr...onnectors.aspx

Heck, I think I'm gonna try this

Adam

PS.: Here is a ready made battery:

http://www.batteryspace.com/li-ion18...lewithpcb.aspx

Last edited by AdamDZ; 12-31-09 at 08:01 PM.
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Old 12-31-09, 08:25 PM   #3
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The circuit board from battery junction would be suitable to fix your pack.
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Old 01-01-10, 07:12 AM   #4
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Yeah, I want to fix my pack but also build a spare.

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Old 01-11-10, 11:29 AM   #5
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The circuit board referenced above did in fact fix my MagicShine battery pack!

Adam
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Old 05-18-12, 05:54 PM   #6
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Hello Adam,

I'm wondering if you or anyone else could be of help. I have a Magicshine light. I believe it's one of the latest models they were offering, but what's happening now is that the light is going blank on me. The battery is charged and I have the same results happening to me on both batteries I have. I can wiggle the light and the cable and get it on again, but it does go out after hitting a good bump or something like that.

I was going to take the light apart and take a look at the connections, but I can't seem to get the disk off of the case. As you can see from the pic, this is about as far as I've been able to take everything apart. I managed to get a small bolt into one of the two holes and tried to pull it out, but it doesn't seem to budge.


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Old 05-18-12, 07:19 PM   #7
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Hi!

You need to unscrew that disk, not pull it. You need something like a spanner, or two small screwdrivers. Insert in the two holes and rotate. Be advised that there might be some thermal paste inside, don't wipe that off, you need it there to transfer heat from the LED to the casing, which acts as radiator.

BTW, are you sure it's not the plugs? The plugs wre known to be problematic and often lose connection.

BTW, those batteries I bought, that are mentioned before are still going strong and both my lights still work well.

Last edited by AdamDZ; 05-18-12 at 07:23 PM.
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Old 05-20-12, 01:15 AM   #8
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Quote:
Originally Posted by AdamDZ View Post

BTW, are you sure it's not the plugs? The plugs wre known to be problematic and often lose connection.

BTW, those batteries I bought, that are mentioned before are still going strong and both my lights still work well.
I'm thinking it maybe the plug too. Seems like I'm getting the short messing with the plug from the battery to the light and also in the light head. I'll lean towards one side or the other if the history tells me that. I just haven't read up on what's happening with the light or anything. I know Geoman has hung it up.

How long are your batteries lasting on full blast? Mine started out at three hours but it has gone down quite a bit. Maybe one hour on full blast?

Sorry for bringing up your thread, I hope you don't mind.
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Old 05-22-12, 07:58 AM   #9
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No problem. I have third party batteries, not the ones the lights came with. Mine still last at least 3 hours on high steady beam after nearly two years.
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