Can I use a Rechargeable 16340 in place of a Lithium CR123A Primary?

[FuzzyPancake]

I found a laser that I am very interested in for its rear toggle switch, <5mW 635nm output, and small form factor. It listed to run on a single CR123A (non-rechargeable aka primary) battery for "up to 36 hours!" (bullshit? Edit: quite possibly not bullshit). For convenience/cost I want to know if I can use a 16340 battery instead. A size comparison can be found below.

From what I've found around the web, the 3.7 volt output of 16340's is a concern as the suggested CR123A operates at 3V, but I don't have the electronics knowledge to understand why that could be a problem. Don't diode drivers regulate current so that voltage fluctuations are a non-issue? Would I risk frying the driver? Would you try to use 16340's? Any other thoughts?

And what do you think of the price and Laserglow as a company?

You can find the laser's specs at Laserglow's website -> Products -> Consumer ->Handheld Laser Pointers -> Taurus -> {Spec Sheet}

 

[Cyparagon]

This really depends on the driver type. If it is a linear or buck driver, the extra voltage won't hurt anything. However, it is common to use a simple dropper resistor (not a constant current driver) in low power reds, because this is good enough, and is of course a lot cheaper. So 3.7V may translate to a lot of extra current.

You can test for the driver type in any laser by using a bench power supply on the input instead of the battery. Begin the voltage at perhaps half expected input, then increase it to perhaps 10% over expected voltage and monitor the current level:

If the current increases at first, then holds around one value, this is a linear driver.
If the current increases, then decreases, this is a buck driver.
If the current increases through the entire range, it is a resistive dropper.

 

[paul1598419]

If that is truly a <5 mW pointer, it could run up to 36 hours on a fresh Li battery. I have some in a flashlight I got over 7 years ago and still going strong. And it uses 5 LEDs..

 

[FuzzyPancake]

You can test for the driver type in any laser by using a bench power supply on the input instead of the battery. Begin the voltage at perhaps half expected input, then increase it to perhaps 10% over expected voltage and monitor the current level:

If the current increases at first, then holds around one value, this is a linear driver.
If the current increases, then decreases, this is a buck driver.
If the current increases through the entire range, it is a resistive dropper.

Sadly I do not have a bench power supply, I do not have access to one, and I do not know for certain how to use one.

I am not the only person out there that has had this question though, so this is surely still very valuable information to somebody in time that does have the resources to experiment and find out in their own device. Thank you for taking the time to explain. I assumed all laser drivers likely had the same structure... granted my knowledge of electronics fundamentals is very limited (but growing!).

If that is truly a <5 mW pointer, it could run up to 36 hours on a fresh Li battery. I have some in a flashlight I got over 7 years ago and still going strong. And it uses 5 LEDs..

I had a strong feeling that the claim was bogus, so this is great to hear. Even if the laser puts out double or triple the rated output (which would suck because I want to use this safely as a kitty cat toy along with just being a neat pointer) It sounds like I'd still have upwards of 9-18 hours of use which is long enough that the somewhat high cost of primary batteries wouldn't be a concern for me.

I had this feeling that it was bogus because I own a chrome pen style <5mW 532mn DPSS green laser that I bought on Amazon circa 2008 that I might get 20 minutes of on time from with fresh AAA batteries. Granted it's extremely hard for me to tell what counts as dead batteries as this laser's output can go from nothing to the beam is visible in thin air depending on the temperature of the diode - with the same batteries. Furthermore, it was only until the last two months that I understood how DPSS diodes are inherently temperature sensitive. Before that I just thought the laser sucked batteries dry quickly and/or had some serious idle draw issues.

 

[paul1598419]

There is a big difference between a direct diode laser and a DPSS one. The pump diode in the 532nm one has to pump 5 times as much power as the direct diode does. Also, there's a big difference between Li batteries and alkaline AAA batteries too.

 

[FuzzyPancake]

I ended up buying the laser with the intention of using the spec sheet's CR123A primaries. Even if the battery only lasts half of their "up to 36 hours!" it'll still take an age for me use it that much. Expect a full review!

 

[Snecho]

I ended up buying the laser with the intention of using the spec sheet's CR123A primaries. Even if the battery only lasts half of their "up to 36 hours!" it'll still take an age for me use it that much. Expect a full review!

I'll be glad to read it. Laserglow used to be touted to be on par with JetLasers and Sanwu before they stopped selling over 5mW to the US.