650nm laser problem?

Dimilo62 · Mar 3, 2012

I got this 650nm 200mw laser from an online website a few months ago.
Unfortunately, I left it in my car overnight in the 20 degree weather. I got it out of my car today only to find that the lasers power has dropped and it is dimmed significantly, probably about 10mw now... :cryyy: any suggestions as to what i can do to fix this or can it even be fixed?

Blord · Mar 3, 2012

Did you check the battery ? They don't like cold weather.
As for the diode they shouldn't be damage by 20 degree.

jcranmer · Mar 3, 2012

Agreed. Let it come up to room temp and replace / recharge the batteries.

Dimilo62 · Mar 3, 2012

yes, i recharged the battery and it still is very dim, i thought the cold weather wouldnt damage the laser either, but its starting to look that way... it wasn't wet or anything like that either, it was perfectly dry

n2stuff · Mar 3, 2012

Check the voltage on the battery. If it was low and you left in the cold you mite have killed it.

Sigurthr · Mar 3, 2012

Yep, my money is on the battery. They crap out easily when undercharged. I never let mine get below 3.3V, not worth the risk.

n2stuff · Mar 3, 2012

Sigurthr said:
Yep, my money is on the battery. They crap out easily when undercharged. I never let mine get below 3.3V, not worth the
isk.

Yep. I have been using li-ions and li-pos for years and they are unforgiving for low voltage discharge. To low and they are gone forever.

Fiddy · Mar 3, 2012

Do a Internal resistance test!

(V1-V2) *R /V2

R = Resistance of load, aim for ~3 - 4 ohms.
V1= Voltage with no load on the battery.
V2= Voltage while under load from resistor R.

---------------------------------------------------------------------------------------

Example:

V1=4.09 VDC No Load
V2=3.97 VDC Loaded
R = 3.1 ohms

(4.09 - 3.97) x 3.1 /3.97

Internal resistance : 94 mOhms
----------------------------------------------------------------------------------------

How to rate a 18650 cells performance:

75-150 mOhm - Excellent
150-250 mOhm - Good
250-350 mOhm - Marginal
350-Up mOhm - Bad

AnthoT · Mar 4, 2012

Ya it's the battery. Here in Canada I've left my laser in my car when it was -12 Celsius and it didn't work.... Until I changed the batteries

-Anthony

Dimilo62 · Mar 4, 2012

thanks for the quick replys guys

but i just tried different batteries, and im still getting the same dim output...
should i just call it quits for this laser ??

Blord · Mar 4, 2012

Hmm, then it must be the laser. Maybe it is just coincident and the laser was dying anyway.
All lasers from China are shipped in bulk freight or ships. It is sometime very cold in the compartments. I can't imagine that they get damage of low temperature.

650nm laser problem?

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