# What are my options for supplying power to an M140 M-Type JAPAN 2+ W laser diode running off of a 5A constant current laser driver? [duplicate]

Background: I am building a laser that is running off of an M140 M-Type 2+ W 445 nm laser diode and an adjustable constant current driver.

Here are the specifications for both the driver and the diode as stated by the seller.

DRIVER
8 - 12V Operation
Adjustable Constant Current Output up to 5A (preset to 500mA)
Suitable for Laser Diodes up to 7W+
0 - 5V TTL/PWM Input Control
0 - 150kHz Frequency
2x 12V Fan Driver
Delayed Startup - <10 Seconds
Includes 2-pin JST-XH Crimp Connectors
Driver is ON by default when powered.

DIODE
This listing is for ONE Brand New Nichia M140 M-Type Japan 445nm 2+
Watt 5.6mm Laser Diode mounted in 12mm x 30mm Metal Housing Module
w/ G-2 Glass Lens, ~6" 22AWG Silicone Leads. The diodes are
meticulously extracted from a new laser diode array. Recommended
current is 1 to 1.6 Amps. A constant current driver must be used to
power the diode. Do not connect directly to battery or unregulated
power supply!


As of now, I have the diode in module with a lens and leads, the driver, and a heat sink which is currently on its way.

Problem:

What I need to do now is supply power to the driver. Since the driver is operational up to 12V, I am considering running 3 18650 batteries rated at 3.7V in series. This will give me a total voltage of 11.1 volts. My concern, however, is that I am unsure if the current of these batteries running in series matters. I know that the current remains the same, however, does the input current need to match the preset current on the driver (500mA)? Does the input current need to be more? If so, how much more? What is a safe amount of current that can be driven to the driver so that it does not break down. I am having trouble understanding how a constant current driver steps down the incoming current without messing up the driver. I apologize if these questions seem silly, but I am genuinely interested in this project, and I would like to power it properly and safely.

Also, how can I calculate the output power of the laser diode? If Watts is equal to voltage * amps, and the driver is sending 500mA to the diode with 11.1 volts, the output power SHOULD be 5.55 Watts. However, this doesn't sound right since the diode is rated at 2 Watts AND since the seller recommends a current between 1.0 to 1.6A. Is my calculation wrong?

Note: My major is in chemical engineering. I am very unfamiliar with electronics. I have tried my hardest to learn everything there is to know in order to successfully build a high-powered laser. If there is anything wrongly stated, please correct me.

• "the current rating of a power supply must be at least what the device wants but there is no harm in it being higher. A 9 volt 5 amp supply is a superset of a 9 volt 2 amp supply, for example." This was very helpful from the post. Thank you. Am I allowed to keep this post up as I am also concerned with other methods that can power my laser, and since other questions are remained unanswered by the thread you referred me to? Thank you. – Andrew J Padilla Jan 6 '19 at 16:46
• You can edit your question to remove the part that was answered by the old question. – The Photon Jan 6 '19 at 19:15