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Old 07-21-08, 10:43 PM   #1
Hirohsima
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Li-Ion Light Battery Question

I have a Niterider Minewt I use as a front flasher and currently charge once a week on the weekends. What is the best charging strategy for Li-Ion batteries? Charge nightly, once a week, or just before fully depleated?

I know Li-Ion has no battery memory, but I would like this light to last me a while.....

Thanks!
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Old 07-21-08, 11:24 PM   #2
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Li-ion is a whole new experience. They don't like being even slightly overcharged or over drawn past certain very specific points. Cell phones, the new lithium tools and other applications that use Lithium batteries use special chargers and have voltage monitors build into the devices themselves that will shut themselves down when the battery reaches this critical low voltage point.

Also you can't use your old sealed lead acid or nickel cadmium or nickel metal hydride chargers with rechargable lithiums. You'll ruin them in no time at all if you try.

So while using lithium cells isn't a bad option it means you're in for the whole enchilada or nothing.

A bicycle light is not a good place to use Lithium cells either since the lights don't have any smarts to monitor the cell's output voltage to ensure that you don't draw them down below their max discharge voltage. Only devices that monitor the voltage and shut themselves off when they hit the low point are good subjects for lithium battery use.

You're far better off to stick with Nickel metal hydride batteries for your headlight.
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Old 07-21-08, 11:28 PM   #3
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Thanks for the info, but the Niterider Minewt comes with a propratary Li-Ion battery so I can't change out the cells.
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Old 07-21-08, 11:38 PM   #4
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Oh, I'm not familiar with all the lights so I didn't realize that it came with li-ion already.

As you say they don't have any memory issues (actually the whole "memory" deal has been engineered out of all the modern batteries anyway. It's amazing how some beliefs linger on.) so you can charge when and as needed. And since your setup came with the right stuff you can charge whenever you think you need it the next day.

If you know it'll last a week on a charge then I'd look at charging it a day or two before you know it'll go dim and shut off. That way you're not being surprised and left in the dark. If it only lasts two days and fades out on the third then charge it on the night of the second day so it's fresh on the "day 3".

If it lasts easily 10 days for your needs then I'd suggest you train yourself to charge it weekly on a given night. That way it's in your regular activities for the week and you won't get any surprises.

The li-ion's are amazing batteries if you give 'em half a chance. They are tough as nails as long as you don't violate those charging or discharging limits.
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Old 07-21-08, 11:52 PM   #5
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Check out these two sites for info on batteries.

http://www.batteryuniversity.com/

http://www.candlepowerforums.com/vb/...isplay.php?f=9
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Old 07-22-08, 12:01 AM   #6
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Ideally keep out in the cold and partially charged. Best strategy would be charge when the red light comes on. If you can keep them in the freezer thats best.
Never store completely discharged.
See wikipedia.
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Old 07-22-08, 12:07 AM   #7
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Excellent, thank you all! Will read up.
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Old 07-22-08, 07:11 AM   #8
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Quote:
So while using lithium cells isn't a bad option it means you're in for the whole enchilada or nothing.

A bicycle light is not a good place to use Lithium cells either since the lights don't have any smarts to monitor the cell's output voltage to ensure that you don't draw them down below their max discharge voltage. Only devices that monitor the voltage and shut themselves off when they hit the low point are good subjects for lithium battery use.
I'm quite certain that the OP's particular model (Niterider Minewt, I own one of these as well) does have the proper circuitry to prevent excessive discharge, so this should not be much of a concern.
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