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View Full Version : do I really need a resistor?



darthdan
02-01-2007, 04:54 AM
From the chart, it shows that for 7.2 or 7.5 volts you would use a 1W 1 ohm resistor for a 5W green. I also know that some can be driven past their typical voltage. Has anybody blown a 5W at this voltage? Has anybody been successful running it straight? Am I just being stupid and should do what the chart says?[/i]

xwingband
02-01-2007, 05:25 AM
Yes do what it says. Batteries have a voltage above what they state when fresh. You don't want to let that voltage to get to it. It's not out of the ordinary for a 7.2 pack to be 8.4V when fully charged.

Marsupial
02-02-2007, 10:08 AM
Moreover, different batteries have different caracteristics.

you can't "assume" a battery pack will be OK without monitoring it - as soon as you change model or company, it can vary a lot in what you'll be able to drain from the battery pack.
Moreover, some (noname) batteries will overheat when supplying the current needed by a luxeon 5.