Originally posted by Orion:
You have on your site (and I have purchased) a 6aa holder to go into a 2D flashlight. Initially, that is 9 volts.
1. Do you know the overall voltage and watts when they are under load driving direct from the 6 AA batteries?
2. Using the 5w resistor, can you give the same answer (voltage/watts)?
I guess with everyone talking about the relatively short life span of the white 5 watters, I was curious if the resistor would prove to increase the lifespan, or if, even with the resistor, it's still being driven at the expense of longevity.
Thanks Wayne! Great products!
<font size="2" face="Verdana, Arial">I don't remember the voltage under load. I do remember some of the current pulled. I can redo the tests, or someone else can if they have time. Voltage is really not as improtant as the current being drawn.
Calculate wattage by multipling voltage and current. If the voltage under load is 7 volts, and you measure .7 amps, the wattage is 4.9 watts.
In order to get a good current reading, use a .1 ohm resistor. Put the resistor in line, and measure the voltage accross the resistor with a DVM. Multiply the reading times 10 to get the current. A reading of 7.6, for example is 760mA. This is more accurate than using the current meter in your DVM.
You will not find .1 ohm resistors at Radio Shack. Perhaps I can buy some and put them up for sale. They are sort of hard to find.
If you use 6AA alkalines, without resistance, the 5W will pull over 1 amp. Can't remember off the top of my head what it is. If you use 6 rechargables without resistance, the current draw could go over 2 amps, so better not do that. You can use a dummy battery, and 5AA's, and be okay direct drive, but only with a cyan. I don't advise going over 700mA for the 5W white. I've gone direct drive from 6AA's using cyan, and also using three CR123 batteries, but don't do this with the white. We want the white to last as long as possible.
With 6AA alkalines, and a 5 watt 2.2 ohm resistor, I measure about 700mA draw. So this is a good combinations. Using 6 rechargables, I also measure about 700mA, so it is still a good choice to use this resistor.
And:
HEAT SINK, HEAT SINK, HEAT SINK!
Wayne j.
