Holy Smoke!

[coachbigdog]

I know this is playin on the edge,but I put 4x123a in a 3c mag with wa01274.I thought 3 was bright.WOW! I took the spring out and put 1 more in and it's like a torch!Livin on the edge is not for the faint of heart! /ubbthreads/images/graemlins/buttrock.gif

 

[js]

You're living on the edge more in terms of the batteries than anything else. At 7.2 volts the 1274 draws almost 2.8 amps. This is more than a single stack of 123's can deliver. Their internal resistance is quite high, and you will thermally shut them down if you try to get this much current from them (and you probably won't get that much current from them). What is your voltage under load? Can you measure the current? I'm guessing you'll see somthing like 7.0 volts and 2.6 amps. This mean a TREMENDOUS internal resistance loss, and a LOT of heat in the batteries. If the internal protection fails, this could be bad. Very bad.

 

[coachbigdog]

[ QUOTE ]
js said:
You're living on the edge more in terms of the batteries than anything else. At 7.2 volts the 1274 draws almost 2.8 amps. This is more than a single stack of 123's can deliver. Their internal resistance is quite high, and you will thermally shut them down if you try to get this much current from them (and you probably won't get that much current from them). What is your voltage under load? Can you measure the current? I'm guessing you'll see somthing like 7.0 volts and 2.6 amps. This mean a TREMENDOUS internal resistance loss, and a LOT of heat in the batteries. If the internal protection fails, this could be bad. Very bad.

[/ QUOTE ]

I only run it for about 1-2 minutes at a time.

 

[soloco]

You are probably not overdriving it by much. 3 123s for the 1274 is actually underdriving it anyway. You'd have to measure the current to see just where you are, but I wouldn't be too worried. I regularly drive 12V 2A bulbs (WA1166 and various MR-16s) with 6 123s in series. That's 18V nominal but about 12V under load.

 

[fivemega]

Current draw using WA1274 with 3 <font color="red">FRESH</font> 123s is about 2.8 Amps for few minutes. And yes, I said "about" because it depends on type of batteries, ambient temperature, flashlight switch resistance and ....

 

[soloco]

So after the first few minutes you are underdriving the 1274. For a 2D sized Maglite, better to use 2 stacks of 3 123s.

 

[fivemega]

In 2D, you can install 3 stack of 123s or 7AA NiMH or 3x2 stack of Pila or....
That's true, 2D is better than 2C and 6D is better than 2D and....

 

[soloco]

How do you get 3 stacks in a 2D?

 

[js]

Yeah,

How DO you get 3 stacks in a 2D mag? Last I check this was not possible without boring out the inside a little bit.

 

[coachbigdog]

Well,she blew last night!So I guess 4x124a's ARE to much for a wa01274.Turned it on and ffffft,out she went. /ubbthreads/images/graemlins/frown.gif

 

[js]

Yeah,

That's because, initially the resistance of the filament is very low, and initially, the batteries can spike a large current in before the internal resitance drags the voltage down. So these together mean for dangerous living when trying to drive a high power lamp to spec or higher with 123's.

I'm sorry, I know that Li chemistry is like the sacred cow of CPF or something, but it is NOT the be all end all of battery chemistries at present. 6 good high current NiMH batteries (or 7) driving the 1274 is a MUCH better choice, because the high current draw doesn't drag the voltage down, and thus your open circuit voltage is much closer to your voltage under load, and thus you can run with a smaller margin.

The best thing, of course, is to use a voltage regulator to run right up to the optimum level of overdrive, and then turn on, open circuit, and hot off the charger voltages are a non-issue.

Anyway, sorry about your 1274. Comes with the territory, I'm afraid.

 

[fivemega]

Here is my 1D M*g takes 6x123 or 3 Pila 168S
Ofcourse some machining required.