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MM and NG with R123/RCR2

this_is_nascar

Flashaholic
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Mar 29, 2002
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Gloucester, New Jersey
I've reviewed a couple threads related to this subject, however none of them seem to provide a definative answer. I have the following emitters attached to either a NG or MM+ convertor board to make a sandwich for various FF-II lights.

TX1J
TXOJ
TWOJ

Can any/all of these runs safely using either the R123 or RCR2 cells? Off the charger, each of these yield ~4.2 volts.
 

Bogus1

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It won't help your with you MM question, but Chop wrote his experience with NG drivers and 4.2V it's ok:

"1. When using a J Vf luxeon with the NexGen biased to deliver 700mA or more to the luxeon.

2. When using a K Vf luxeon."
 

wasBlinded

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What happens to a Nexgen biased at less than 700 mA? Is there a particular component that is overstressed by the higher voltage/current in a lower biased circuit than it is in a higher biased circuit?
 

cy

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Dec 20, 2003
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MM boards are voltage regulated, so vf determines current draw. wayne's got a chart somewhere that lists vf to current.

BB are current regulated so VF doesn't determine current to lux. but vf does effect runtime.

I've run loads of cycles with li-ion on both. general rule of thumb is Jbin is safe to use with li-ion. Hbins depending on how low can toast. when VIN exceeds VF, you are direct driving, less burden of circuit.

don't know about next gen..
 

knifebright

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sanfran by way of boston
Nexgens and madmax can handle overdrives but it depends on vf.
madmax is something along the lines of Vin (under load) plus .2 needs to be less than Vout(forward voltage).

Nexgen is Vin(underload) plus .8 needs to be less than Vout (forward voltage) for drive currents under 700ma. For over 700ma your usually pretty safe with a jbin or above.
jimmy
 

srue

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Dec 6, 2003
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Salem, OR
Ray,
Let me first say that the three emitters you listed above all have the same capability (for better or worse) to run safely off a Li-ion cell. That is, they are all J binned Vf. The tint (the X1, XO, and WO parts) don't affect the voltage characteristics.

That being said, when attached to a NG, you should have no problem running any of these off either a R123 or RCR2. I've run a TWOJ NG750, a TWOH NG866, and a TY1K BB650 all off various R123 and RCR2 cells. None of these have suffered any ill effects that I can see. I've never tried a MM or MM+, so I don't know how those would react.

The output will be brighter with the li-ion cells, since overdriving the voltage will cause the current draw to increase. It's possible that this will cause long-term damage to the emitters or to the circuitry. But it hasn't happened to me, or if it has happened, it's been too slow for me to notice.

Hope this helps.

-Stuart
 

srue

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I'm pretty sure NG's are not designed to protect against over-discharge. There may be a de facto protection since the converter will not light up below a certain voltage, but by that point you've probably already partially damaged the cells.

The trick is to just pay attention and regularly recharge your batteries. And if you do happen to ruin a few cells, new ones are available pretty cheap from AW (here).
 

knifebright

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Aug 23, 2004
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sanfran by way of boston
The nexgen will flicker with a ***J when
Vin(underload)*1000 less than or equel to Vout(forward voltage)*amperage bias(this case 750)
example

r123 under load=3.4 volts
forward voltage on j=3.47
3.4*1.000<3.47*.75

this is a worst case senerio and you'll still be at 2.6 volts in the battery when it flickers out. Plenty safe.
jimmy
 
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