Laser collimator - new battery - not very bright

[cbbella]

Hi, I have a next generation laser collimator.  I have been trying to collimate it and eventually succeeded.

The trouble with it is that even with a brand new battery showing 3.26 volts the laser seems very dim even on its highest setting and is barely visible when shining it on a wall 10ft away across the room and when using the barlow method to collimate my scope its nigh on useless as it is so dim I cannot make out the donut on the primary mirror

The pictures I've attached were taken in the daytime and seem bright enough in the pics but we all know the camera is much more sensitive but in reality and with the naked eye I can only just see some colour from the laser. 

I've also attached two pics taken in a completely darkened room showing the barlow method and even in complete darkness its still very dim.

Another thing is that when I opened the laser to see what was going on with the screws when I was having trouble collimating it i found that there was a deformed spring inside that I have no idea where it should go.  Does anyone know why or what this spring is doing in there.  This is the first time its been opened since I purchased it brand new from an online astro shop a long time ago

Edited November 17, 2023 by cbbella

[Mandy D]

The first things I would check is the quoted power output and wavelength. At 670 nm you are approaching the long wavelength limit (700 nm) of human vision. Compare a helium neon (HeNe) laser spot at 0.5 mW and 632.8 nm wavelength with a 670 nm diode at 3 mW. The HeNe will appear much brighter, due not just to improved sensitivity, but it usually produces a tighter collimated spot.

[cbbella]

4 minutes ago, Mandy D said:

The first things I would check is the quoted power output and wavelength. At 670 nm you are approaching the long wavelength limit (700 nm) of human vision. Compare a helium neon (HeNe) laser spot at 0.5 mW and 632.8 nm wavelength with a 670 nm diode at 3 mW. The HeNe will appear much brighter, due not just to improved sensitivity, but it usually produces a tighter collimated spot.

This all i can see of what is left of the label

Wavelength: ??? - 655nm

Output: < 1mw

[Mandy D]

OK, it should have a reasonable apparent brightness at that power and wavelength. Have you checked the battery under load in the laser? Measuring the terminal voltage of a cell off-load indicates nothing. I've seen button cells give the reading you have off-load and fall to practically zero under load. I know you have said it is brand new, but it could be faulty or old stock, still.

[cbbella]

I'm not sure how to check it under load, I'll have to Google that lol. just know how to check the voltage as I have done

[Mandy D]

The link, below, suggests that a 1 mW laser diode draws 20 mA.

https://botland.store/laser-diodes/15386-laser-diode-1mw-red-650nm-5v-velleman-wpm434-5410329725501.html

So, if you cannot measure the voltage when the battery is in the laser, connect a 150 ohm resistor across the battery and measure the voltage across it with your multimeter. If it falls over time, or drops immediately to low values the battery is no good.

[wookie1965]

I have had a few button batteries in packets new fail, one only a week ago when I changed my car key battery.  Put a brand new one in key did not work checked the battery 3.3v but just to make sure opened another put that in and worked first time, so obviously first battery was faulty.