This may be a stupid question...

...but I'm not that strong into electronics.

OK, I have this PL450Bdiode with a Moghasm 100mA linear driver. I feed it with 2 1634 cells.

That works just fine, but I want to use this laser for a different purpose, actually for targeting.

For that, it would be of more convenience to feed the laser from a 9V block. Can I just do that or will it fry the diode/ driver?

Two 16340 batteries full charge are 8.4 volts if the driver handles that then 9 volt battery isn't much more. But a 9v battery has 6 x 1.5 v cells in it at low current capacity .So the life of the 9 volt battery would be fairly short as the current capacity is on one cell only. Which will not be much, i would stay with the 2 x 16340 to be safe as the extra voltage will be wasted as heat. Also you may be getting close to what that driver can handle i think it is 12 volts but if its not then you may be at risk of reducing the life of your driver board at least.Do you plan to have 9v rechargeable batteries as they are fairly expensive .......my advice stay with the 16340s

Thanks for thuis information, Blaster. I will think about a different solution.

No worries ...glad to help