starburst
Newly Enlightened
Wondering if 3 D alkalines direct drive would be to much for a Seoul P4 USWOH
SSC P4 direct drive
- Thread starter starburst
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Alin10123
Flashlight Enthusiast
starburst said:
I want to say yes. You'd probably need a little bit of resistance in there. Of course... i could be wrong.
Alin10123
Flashlight Enthusiast
Nake said:
Either that or... a really really really big heatsink. lol
lexina
Enlightened
- Joined
- Jul 3, 2005
- Messages
- 782
The "H" bin is rated at 3-3.25Vf. If you use the resistor calculator on this page:-
http://www.luxeonstar.com/resistor-calculator.php
and input 4.5V for supply voltage, 3.25 for forward voltage and 1000mA for operating current, it will suggest a 1.5 ohm (nearest to 1.3 ohm) 2W resistor and result in actual current of 833mA.
Bear in mind however, that the calculator ignores resistance that might be present elsewhere such as the tail-cap spring, the mag switch, wires etc. You can therefore probably discount the 1.5 ohm by 20-40% depending on your actual setup.
I have been running a Seoul P4 USWOI ('I" bin = 3.25-3.5Vf) on 3 C-NiMh direct without any resistor and it works fine (around 900mA from freshly-charged cells).
http://www.luxeonstar.com/resistor-calculator.php
and input 4.5V for supply voltage, 3.25 for forward voltage and 1000mA for operating current, it will suggest a 1.5 ohm (nearest to 1.3 ohm) 2W resistor and result in actual current of 833mA.
Bear in mind however, that the calculator ignores resistance that might be present elsewhere such as the tail-cap spring, the mag switch, wires etc. You can therefore probably discount the 1.5 ohm by 20-40% depending on your actual setup.
I have been running a Seoul P4 USWOI ('I" bin = 3.25-3.5Vf) on 3 C-NiMh direct without any resistor and it works fine (around 900mA from freshly-charged cells).
baylisstic
Enlightened
You'll need a resister. I killed an H bin from running off 3D without a resister. An I bin without a resister is fine though.
starburst
Newly Enlightened
Thanks to everyone for the info.
I mounted a star to a 1 inch in diam by almost 1 inch long brass sink. The host
is a coleman lantern type light red and black the head swivels up and down the
original setup was 4D I used a heavy wire to jump over one of the battery bays
to make it 3D hoping this would add some resistance to the setup. there is prob
1 foot of wire for the current to run through before it reaches the P4. the reflector is 2.5 inches by 3.75 inches and close to 3 inches deep. A real flood
monster. I have ran it 4-5 min. 3 or 4 times on Alkies seems to be OK I just dont
want to burn it up now what do you think run or resistor?
I mounted a star to a 1 inch in diam by almost 1 inch long brass sink. The host
is a coleman lantern type light red and black the head swivels up and down the
original setup was 4D I used a heavy wire to jump over one of the battery bays
to make it 3D hoping this would add some resistance to the setup. there is prob
1 foot of wire for the current to run through before it reaches the P4. the reflector is 2.5 inches by 3.75 inches and close to 3 inches deep. A real flood
monster. I have ran it 4-5 min. 3 or 4 times on Alkies seems to be OK I just dont
want to burn it up now what do you think run or resistor?
Alin10123
Flashlight Enthusiast
I think it depends. Alkalines, you could probably get away with it with good thermal management. But if you want Nimh...
kenster
Flashlight Enthusiast
Wow! This is intersting to me. An 'H' vf binned P4 is 3.0 to 3.25 volts at 350ma isn`t it? Raise the current beyond 350ma and you are going to raise the vf beyond the 3.0 to 3.25 volts. How are people getting over 1 amp direct drive on a single Li-on? None of the 'H' vf binned P4 I have will get to 1 amp even with a cell straight off the charger???
Starburst, I am not trying to change the point of your thread. I think my post explores your question further.
Ken
Starburst, I am not trying to change the point of your thread. I think my post explores your question further.
Ken
Last edited:
starburst
Newly Enlightened
Where can I get some USWOI bin P4s? :thinking:
lexina
Enlightened
- Joined
- Jul 3, 2005
- Messages
- 782
starburst said:
Litemania has them (as well as heatsinks) here:-
http://www.candlepowerforums.com/vb/showthread.php?t=153522
AndyTiedye
Flashlight Enthusiast
What is the internal resistance of 3 D alkaline batteries?
cratz2
Flashlight Enthusiast
I'd resistor it with about a 2 Ohm resistor. Here's rationale. You aren't likely to be able to see the difference without comparing the true direct drive side by side against the resistored one. You'll get a bit longer runtime with the resistor. AND you are helping protect the LED. Seems like a win/win/win solution to me.
moon lander
Enlightened
check the current in direct drive, if its too much try .5ohm or 1 ohm resistor. alkalines will probably give you plenty of resistance, tho the bigger the cell, the less resistance it will give you. nimh cells have very low resistance and may need a resistor. if you have a good heatsink, you should be able to run it at around 900ma without much heat problem.
Virtually all DMMs will drop the voltage by ~.1 V per amp since they generally use a .1 ohm resistor in current mode and measure the voltage drop across it. Fluke is one of the few who actually spec the "voltage burden" on some of their meters. Even on the ~$400 187/189, it's about .04 V / A.
The SSC P4 Vf curve is pretty steep around 1 A and that extra .1 V to the LED could mean as much as 300 mA more than you measure when the DMM is not in the circuit. Of course the battery voltage may droop a bit more under the higher load but he actual current without the DMM in the circuit will still always be more than you measure on a direct drive or resistor limited set up.
The GD converters from the Sandwich Shoppe are worth considering. I got one configured at 833 mA for an SSC P4 modded Dorcy 3D that I'm going to try hopefully this evening.
Mike
The SSC P4 Vf curve is pretty steep around 1 A and that extra .1 V to the LED could mean as much as 300 mA more than you measure when the DMM is not in the circuit. Of course the battery voltage may droop a bit more under the higher load but he actual current without the DMM in the circuit will still always be more than you measure on a direct drive or resistor limited set up.
The GD converters from the Sandwich Shoppe are worth considering. I got one configured at 833 mA for an SSC P4 modded Dorcy 3D that I'm going to try hopefully this evening.
Mike
starburst
Newly Enlightened
My $30 radio shack DMM shows .710 on my lantern P4 mod.
my second P4 mod is a 3D m*g it reads .760 with two solder joints
on a heavy wire between the switch and the led seems to knock the
power down some. My third mod a 3D m*g with P4 has only one solder
joint using smaller guage wire it shows .910-.920 on the meter.
The first two mods seem to run cool. The first one got a brass heat
sink, the second one got a XL copper sink which doesn't even seem to
get warm.The third mod I used a large Aluminum sink the head seems
to get a little warm after 10 min. not sure yet but it may need a small
resistor at .910 the P4 is blinding bright thats for sure!!!
Thanks to all for the coments and info as Im still learning I greatly appreciate
it very much!!! :thumbsup:
my second P4 mod is a 3D m*g it reads .760 with two solder joints
on a heavy wire between the switch and the led seems to knock the
power down some. My third mod a 3D m*g with P4 has only one solder
joint using smaller guage wire it shows .910-.920 on the meter.
The first two mods seem to run cool. The first one got a brass heat
sink, the second one got a XL copper sink which doesn't even seem to
get warm.The third mod I used a large Aluminum sink the head seems
to get a little warm after 10 min. not sure yet but it may need a small
resistor at .910 the P4 is blinding bright thats for sure!!!
Thanks to all for the coments and info as Im still learning I greatly appreciate
it very much!!! :thumbsup:
