# Magicshine battery problem



## SilverXC (Feb 18, 2009)

I've make short circiut when i checked battery voltage with my voltometer.
At first light shined normaly, and after 1,5 hour on the high mode, light started to blink faster and faster-some kind of stroboscope. I have changed the battery and it's ok.(i have two batteries)
The wrong battery have 5,55V so it is not discharged.
I have opened the battery and PCB looks OK

Can anyone help me? I can't ride on strobo 

P.S.Now, when I plug the light to the damaged battery, in the early it shines at 100%, after a while it begins slowly to go about 50% and then starting to flash...


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## gmcttr (Oct 7, 2006)

Have you tried charging it???


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## SilverXC (Feb 18, 2009)

I wanted to check them first- 5,5V
When im plugging it, the charger make squeaking noise. After while when im pulling out the charger with battery conected, the led on the charger turns green
I assume when the battery is fuly charged is ok with the light, when the battery is a little discharged is making the blinking things but im not for sure.

I will charge the battety and see what will happen when i will be using it...


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## SilverXC (Feb 18, 2009)

I charged the battery for about 30min = 7,4V it shines normally, until light recieves about 5,9V then it start to blink.
Maybe its not battery failure, and battery short circiut has nothing to do with the blinkig, maybe its the light PCB failure ? 
(I have to check and discharge the other battery, if it gives the same symptom)


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## kwarwick (Jun 12, 2004)

SilverXC said:


> I wanted to check them first- 5,5V
> When im plugging it, the charger make squeaking noise. After while when im pulling out the charger with battery conected, the led on the charger turns green
> I assume when the battery is fuly charged is ok with the light, when the battery is a little discharged is making the blinking things but im not for sure.
> 
> I will charge the battety and see what will happen when i will be using it...


5.5V is too low. Fully charged the battery should be around 8.4V and fully discharged is typically 6V. Assuming you've got an accurate meter and its reading 5.5V the battery is either over-discharged and/or damaged.


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## gmcttr (Oct 7, 2006)

It also takes 4 hours+ for a full charge.


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## SilverXC (Feb 18, 2009)

kwarwick said:


> 5.5V is too low. Fully charged the battery should be around 8.4V and fully discharged is typically 6V. Assuming you've got an accurate meter and its reading 5.5V the battery is either over-discharged and/or damaged.


I used the light only couple of times. First time on the other battery it shines for 8hours (on low -3mode light) and after that it turned off. 
I have checked on the voltometer and as I remember it shows 0V. I have charged that battery and it is OK. 
Now I'm using the other battery and it start to blink @ ~5,5V
So, do You have about 5V when the light turns off? (I know it should be a bit charged to avoid over-discharging)



gmcttr said:


> It also takes 4 hours+ for a full charge.


Yes I know, but i wanted to check if the light blinks when it is more charged.
I think blinking isn't normal behaviour of this light


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## chelboed (Jul 29, 2005)

Get it replaced before it goes up in flames.


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## gmcttr (Oct 7, 2006)

SilverXC said:


> I charged the battery for about 30min = 7,4V it shines normally, *until light recieves about 5,9V* then it start to blink.


Both of my MS lights go into a reduced output strobe/fast blink instead of just cutting off when the battery is run down. This matches your description.

Give the battery a full 4 hour charge and then see if you get full output for 3+ hours. Just don't run it on high for an extended period without providing airflow for cooling.


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## SilverXC (Feb 18, 2009)

gmcttr said:


> Both of my MS lights go into a reduced output strobe/fast blink instead of just cutting off when the battery is run down. This matches your description.
> 
> Give the battery a full 4 hour charge and then see if you get full output for 3+ hours. Just don't run it on high for an extended period without providing airflow for cooling.


Thanks for that information.:thumbsup: 
I've worried because as I write earlier, on the other battery pack, light just cut off. And I read somewhere that the light just do that. 
So strobe for me was abnormal behaviour.(practically it is better thing than cutting off light)
Now it looks like i have took out the cells from original package for no reason  
Well, I have to see if this situation with both battery pack after full charge will repeat.


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## MtbMacgyver (Jan 23, 2007)

Here's what I think is happening.

On the first battery, the one that cutoff after 8 hours on low, I think that battery cutoff due to the low voltage cutoff built into the protection PCB inside the battery pack. The reason I think that is because when that happens, the protection PCB stays off until charging resets it. That's why you didn't get the strobe effect and also why that pack shows zero volts with a meter. If you connected that pack to the charger for a few second to reset the protection PCB, you would get a voltage reading with the meter. It would likely read somewhere between 5.5 and 7.4 volts.

On the second battery, the one giving the strobe effect, the protection PCB in that pack must be a lower cutoff than the other pack or the protection PCB is not functioning at all. There is some variance in cutoff voltages due to manufacturing tolerances. To explain what's happening with that pack, we have to talk a little bit about how the electronics in the magicshine light head work. The microcontroller inside the magicshine light head does not implement an explicit low battery cutoff voltage limit. It would be good if it did, and 6V would be the right cutoff, but it doesn't. It just so happens that the regulator chip used on the driver board stops working right around 5 volts. That also varies some from light to light. Since both those things happen right around 5 volts, it ends up being somewhat random as to which thing happens first when you're dealing with different combinations of light heads and battery packs. But, most of the time the pack low voltage cutoff does happen first. 

So when the input voltage gets to the 5 volt range, the main LED goes off. But, the microcontroller on the driver board hasn't actually turned the light off, and it still thinks the light is running, just the regulator chip itself has shutdown. That takes 95% of the electrical load off the battery pack, which causes the voltage of the battery pack to rebound slightly. The rebounding voltage causes the regulator chip to turn back on and hence you get a cycle that causes the strobe effect. 

The moral of all this, don't run the magicshine light down much past the indicator light on the button turning red. The indicator light does turn red at around 6.5 volts. That indicator does tell you when it's about time to turn it off. Just keep in mind that on the magicshine light, there is one IC that controls the low battery indicator light and another microcontroller based IC that controls on/off and the brightness levels. Those 2 ICs do not talk to each other. So the main control IC doesn't do anything or even know the status of the battery voltage. So the red indicator light is a signal to the user that it's time to turn if off, that's all you get. If you let the light run until it the main LED goes off or starts the stobe effect, you're not being kind to your battery pack. It won't absolutely kill it because the low voltage protection will eventually kick in, but it's not really great for the pack either. 

Both batteries should charge back up ok. But, it's kinda tricky to test if the protection PCB on that pack is just low or completely broken. Since being completely broken could be a serious safety concern, you may want to return that pack to the place of purchase for evaluation. 

If you do want to test it yourself, you'll need a variable power supply, some type of load besides the magicshine light head, and a meter wired up so you can watch the voltage while discharging and charging. On discharge, if the pack doesn't shutoff by 5.0 volts then it's broken. On charge if the pack doesn't shutdown by 8.7 volts then protection PCB is broken. Just don't let it go at all outside those ranges and do all this with precaution for fire both during the test and 12-24 hours after the test.


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