Mc2s resistor values***UPDATE***

[SilverFox]

Hello Don,

I am ready to get one of these two stage tail caps for my L4. I was just trying to figure out what resistor value to choose. This thread has not been much help because I run Pila's in it.

Craig's has the 22 ohm in it and it seems that it dropped the light to a very low value. I am thinking of a little brighter low setting.

Any suggestions?

Tom

 

[McGizmo]

Tom,
I just haven't had a chance to mess with the Pila's and KL4. I am up to my ears in the Aleph parts still in process. I have asked wptski to shed any light he might have on this. I would guess that you will want somewhere from 7.5 ohm to 15 ohm for your rig but I have no great feel for this. I would guess that there are folks using these combos but they either have not seen this thread tucked away here or have chosen to remain silent. If the latter, shame on them!! /ubbthreads/images/graemlins/nana.gif

 

[wptski]

Okay, PilaTalk! /ubbthreads/images/graemlins/grin.gif

KL4
max=762 lux
15 ohm=58 lux
22 ohm=37 lux
30 ohm=26 lux
60 ohm=9 lux

Lux-III DB917
max=2387 lux
15 ohm=361 lux
22 ohm=256 lux
30 ohm=189 lux
60 ohm=89 lux

Lux-V BB750
max=1277 lux
15 ohm=61 lux
22 ohm=39 lux
30 ohm=26 lux
60 ohm=11 lux

All readings taken with a LM631 at one meter with ambient light subtracted from readings.

I use a Lux-V BB750 with a 1.7 ohm at work which gives me 400 lux. I would have included it in the readings but it's at work! Not sure if anyone would be interested in that much light anyway?

I perfer more light and must have at least six 15 ohm Mc2E's all together, some of which are for future use.

I perfer the Lux-V with the larger spot but do have several Lux-III, some have UCL/LDF lens which softens the spot nicely altough it really cuts the lux value. I can take some readings on a Lux-III DB917 with a UCL/LDF lens installed if anyone wants?

I'm wondering how a BE4 powerpack with be with 2x168S? If I like a 15 ohm with one Pila, will I perfer a 30 ohm since the voltage is doubled? The lower the voltage of the Pila required a lower the resistor value.

We should have the JSB123 Li-Ion shortly too!

 

[McGizmo]

Great post and info! Thanks Bill!!! /ubbthreads/images/graemlins/thumbsup.gif

 

[SilverFox]

Hello Bill,

Thanks for the information.

Don,

I am looking for a little bit more brightness on low. What values of resistors are available in the 7.5 - 15 ohm range? Is there a 10 ohm resistor?

Tom

 

[wptski]

Don/Tom:

Your Welcome! /ubbthreads/images/graemlins/grinser2.gif

 

[McGizmo]

Tom,
10 ohm is available from three 30 ohm resistors, no problem.

 

[SilverFox]

Hello Don,

OK, I'll take one in HA natural finish.

I'll send you an email for the actual order.

Tom

 

[wptski]

[ QUOTE ]
SilverFox said:
Hello Bill,

Thanks for the information.

Don,

I am looking for a little bit more brightness on low. What values of resistors are available in the 7.5 - 15 ohm range? Is there a 10 ohm resistor?

Tom

[/ QUOTE ]
Tom:

By calcutions, a 10 ohm should give you about 65 lux.

 

[SilverFox]

Hello Bill,

Thanks. When I get it I'll post my actual results.

Two more questions, since you have a formula handy:

Best guess with 10 ohms running CR123's?

Best guess with 10 ohms running R-CR123's (about 8 volts)?

I tried my L4 with 2 R-CR123's and it worked, but I was not sure if the L4 could handle the higher voltage. It works well on 1 R-CR123, but the Pila has more capacity (longer run time).

I guess a question for Don would be if the tail cap can handle R-CR123's (a little over 8 volts)?

I am going to have some fun with this set up.

Tom

 

[McGizmo]

Tom,
Your resistor PCB consists of 3 ea. 30 ohm 1/4 watt resistors in parallel. You have a .75 watt rating on the resistor PCB. The thermal relief on the resistors might allow them better power handling but I leave that to the EE gurus. 2 RCR123's is flirting with disaster, IMHO and will depend on how much current they can deliver. The L4 is in DD at 8 volts. You might be pushing it with 2x CR123's, I just don't know off hand. /ubbthreads/images/graemlins/icon3.gif Had I known you were going to play with these combos, I think I would have put 6 ea. 60 ohm 1/4 watt resistors on the the PCB and then let you cook off something other than the resitor PCB! /ubbthreads/images/graemlins/tongue.gif

 

[SilverFox]

Hello Don,

OK, I'll limit my playing to the Pila's. That is the combination that I use most of the time.

I do like to throw CR123's in for camping. I'll just revert back to the SF tail cap when I do that.

Thanks for the information. I'll try hard not to burn things up. /ubbthreads/images/graemlins/smile.gif

Tom

 

[wptski]

[ QUOTE ]
SilverFox said:
Hello Bill,

Thanks. When I get it I'll post my actual results.

Two more questions, since you have a formula handy:

Best guess with 10 ohms running CR123's?

Best guess with 10 ohms running R-CR123's (about 8 volts)?

I tried my L4 with 2 R-CR123's and it worked, but I was not sure if the L4 could handle the higher voltage. It works well on 1 R-CR123, but the Pila has more capacity (longer run time).

I guess a question for Don would be if the tail cap can handle R-CR123's (a little over 8 volts)?

I am going to have some fun with this set up.

Tom

[/ QUOTE ]
Tom:

I really don't have a formula but the values seem to double as the resistor is halfed! Using K-T's chart, I'd say that 2x123 with a 10 ohm would be just under 200 lux. No idea about the R-CR123!

 

[SilverFox]

Hello Don,

I received the tail cap and must say that it is a most excellent addition to my L4. Nice job.

Mine has a 10 ohm resistor in it. I am measuring foot candles at 1 foot which equals lux at 1 meter, in a dark room.

Using 1 R-CR123:
722 fc on high
62 fc on low

Using a Pila 168S hot off the charger:
746 fc on high
86 fc on low

I believe the lower value with the R-CR123 is because I have to use a spacer and that adds a little extra resistance.

Bill, your guess of 65 on low was very close.

Tom

 

[SilverFox]

Hello Don,

I did a run time test on low with my L4, Pila 168S, and 10 ohm in the tail cap.

At 10 hours 30 minutes the light level had dropped to half of what I started out with (86 fc down to 41 fc), at 11 hours 22 minutes I could look directly at the LED without any discomfort and decided to end the test.

Now I must tell you that I cheated a bit during this test. After six hours of continuous on, I would turn on the high setting for about 10 seconds every hour. I was curious to see if there was anything left in the battery to fire up on high. At the 11 hour mark, there some flickering, but it finally made it and held for the full 10 seconds.

I am very impressed...

Tom

 

[cia]

I have the 15 ohm switch.
I turned it on at 12:00am and went to bed.
When I got up at 7:00 am it was still going, looked very bright yet on low.
I checked to see if high power still worked and it did.
I played with the high power on and off a bit and then turned it off.

I took the batteries I had in it out and put in new ones before going to work.

I will put the other batteries back in it tonight and see how much longer it will run on low.

I'am also very impressed....

Thanks Don, /ubbthreads/images/graemlins/smile.gif

Edited to add: Ran it a second night on the same set of batteries. It was still running after another 7 hours, preaty dim at this point. I would say about as bright as a L1 on low. Could still use it to get around the house and pitch black basement this morning.
Would also fire up high yet, but high was not the full high power that the L4 can put out, not even close. Could not expect anything better after so many hours of run time, thanks again.

 

[McGizmo]

Cool guys! /ubbthreads/images/graemlins/grin.gif

 

[Haesslich]

Say, how's Cambria, if you've already arrived? /ubbthreads/images/graemlins/grin.gif

 

[McGizmo]

Nice! Foggy out now! /ubbthreads/images/graemlins/grin.gif I forgot my power supply for the laptop but my wife Fed EX'd it so It *should* arrive tomorrow. /ubbthreads/images/graemlins/icon15.gif On battery with no means of recharging so on to E-mails and then off the computer! /ubbthreads/images/graemlins/wink2.gif

 

[Haesslich]

Enjoy the trip. Currently awaiting the combined mercies of Canada Post and USPS now. Wanting to try Aleph 3 versus Aleph 2 in real-life conditions after work - residential area, complete with school and unlit parks. /ubbthreads/images/graemlins/grin.gif

Of course, I'll need to use TWO nights for the tests. Have some Ceramique coming in too, since that stuff melts with isopropyl alcohol. Will that damage the coatings any, should any get into the reflector?