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using RC rechargeables???

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mw1111

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ok i have heard that the GB DIY red torches need at least 6V with daedals circuit (which i purchased from him directly, so that will be in perfect working order im sure)

what i can tell from this battery is that

A: it is 9.6 V so it is well above 6V but still below the maximum voltage

B: fully rechargeable, and i have about four of these packs

C: seems to have 8 AA's inside of it

D: it is a nickel-cadmium battery, no lithiums for me!




so what do you guys think, will it give me a quality beam, at a stable rate, (in other words, will the beam get brighter and then dim even on a full charge, like my DX 5mW???)
 





Benm

Benm

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It will work fine, no problems to be expected with the beam dimming at all until the batteries are totally dead. The only thing is that the LM317 might get a bit warm, depending on how much current you set it for.
 
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mw1111

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i'll have to ask daedal how well, or if at all, he heat-sinks his LM317's.

what might a duty cycle be with a normal unheat-sinked aixis module 140mw with his circuit and a 9.6V battery?
 
Benm

Benm

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140 mW would be around 250 mA from the power curves members here tested.. so the LM317 would dissipate 250 mA x ca. 5 volts, or 1.25 watts. This will make it run quite hot, but is acceptable for continous use as long as it has some air circulation.

For the diode, it's hard to give a good answer. It will obviously get warm which results in lower optical power output, but probably not warm to the point where it will rapidly damage the laser diode.

But 140 mW CW is driving it quite hard already, so diode lifespan will be limited anyways, which is probably worsened by the higher temperature.
 
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a_pyro_is

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Sorry Benm, but I must dissagree with you. At that input voltage, without heatsinking a free-standing 317 would go into thermal overload protection mode in just about 3 minutes. That input Voltage would be perfect for a BluRay, but IMO a bit too high for a red without heatsinking the 317.
My favorite is still a 6 cell NiMH battery. A few extra bucks to get started, but no need to buy batteries for a long time.
 
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a_pyro_is

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Just checked and my math was pretty close.

New RatShack LM317 left the leads long placed 2.5" inside a 1.25" Dia. PVC pipe w/ endcap at opposite end (one end open).

Vin = 9.6 V
Vout = 2.82 V
Iout = .245 A

Thermal shutdown started just before the 3 minute mark. But I'm certain that with just a little bit of heatsinking it could keep running much longer.
 
Gazoo

Gazoo

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I use the little clip on heat sinks for the TO-220 package and have not had any thermal shutdowns, but my regulators are not enclosed. Nevertheless, this is a another reason the AMC7135 rules over the LM317 for use in portables.
 
Benm

Benm

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a_pyro_is said:
Sorry Benm, but I must dissagree with you. At that input voltage, without heatsinking a free-standing 317 would go into thermal overload protection mode in just about 3 minutes.
Click to expand...

It does? I was referring to the LM317 in a TO-220 package btw, perhaps yours has a smaller enclosure? Thermal resistance to ambient should be 50 K/W or so for a TO-220. On paper it should drop out when it reaches 150 degrees, but in practice that might not work out that well - i guess ;)
 
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mw1111

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im sorry if this causes any confusion, but does anyone know the actual part that Daedal uses in his PSU's? i will be making this a semi-labbie (sticking it into a CD face-case, about 9" long and 2" wide") so it wont be as enclosed at a normal pen/flashlight laser is
 
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a_pyro_is

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Mine was the Radio Shack TO-220, and I enclosed it so that there was almost no air movement. Maybe I've just got a bad lot, but at just under the 3 minute mark the current started dropping rapidly.
It was VERY hot after the test, easily over 100C. I don't know what the Specific Heat of a TO-220 LM317 is, but it's not very much. But on the same note, it's easy to remove that heat with a tiny bit of heatsinking.

mw1111 said:
im sorry if this causes any confusion, but does anyone know the actual part that Daedal uses in his PSU's? i will be making this a semi-labbie (sticking it into a CD face-case, about 9" long and 2" wide") so it wont be as enclosed at a normal pen/flashlight laser is
Click to expand...
Is this the link you're looking for?
 
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Phazonx

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I'm using one of those 9.6 volt packs. I prefer the Ni-MH though. I've gotten a total of 7 hours on a battery charge.
 
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mw1111

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holy S*** seven hours on a single charge with these?

oh and if someone could draw me up a way i could use a fan with this setup, i have a 52MM fan that will easily fit in my case, and i could punch some holes in the case for some air flow, but how could i hook it up?
 
Benm

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If it's a 12V fan, you can connect it to the batteries directly. I will run a bit slower than normal on 9.6 volts, but work quite well and be a bit quieter than normal too.
 
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wooooooolazer

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Ive put a 12v .04A fan on mine to i just put a 9v battery to it and it still runs pretty good blows decent and i drilled holes under the aixis module to get air flowing around it, i know just need to get my lm317 some air flow to i put it on a breadboard tho so it might be kinda hard might just try to get a small heatsink from somethin i have around.



....lazer..... ;D ;D ;D
 
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a_pyro_is

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Off topic, but
breadboard = big danger to LD
one loose connection and poof goes your shiny red.
I learned the hard way. ::sigh:: man that diode was a good one.......
/me recalls burning helpless insects.
LOL sorry my head is still stuck in a few other threads
 
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wooooooolazer

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Actualy i dont think it is a danger because i made sure and soldered the cap directly onto the diode and its a big one to 25v 100uf,  and i made sure to cover up the breadbord with clear celephane tape to prevent it from touching anything is it still bad?


Offtopic but the diode im using is kinda underpowerd because i tried shaving the plastic under the colaminator lens on the aixis housing and i left a small peace of plastic acidentaly and it fell on the diode and melted so theres a black spot where no light can get through, The other diode i have luckly is a realy nice red blob not with random black spots like the one in it, i cant wait to try the new one out i can already light a match with the one i have now cant wait to find out what that can do!







....lazer..... ;D ;D ;D
 
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