Question RE: fan power

[JimBolder]

I'm building a 445nm pseudo-labbie right now that runs on 4 3.7v 18650's.

Basically, I want to include a fan to blow air through my diode's heatsink and its driver heatsink (I'm going to power it with a linear driver).

I have a couple fans on me right now, but they're all either 12v or 24v. I'm thinking about using a 12v fan, which means I need to wire the batteries in series.

The problem is, I think that ~15v would be a little much for the laser driver.

Should I put a couple of diodes on the driver to drop the voltage a little or something? Or is it just fine as-is when properly heatsinked?

Also, do I need to build some sort of driver for the fan? If so, would a simple LM317 linear driver suffice? (It's a 170mA fan, btw.)

Sorry guys, I'm no electrical major. :thanks:

 

[Leodahsan]

Why you are using that much batteries? You can use a boost driver (you will need to design and build one) for that fan I think. Wire they in parallel or you will get VERY short runtimes for a labby...

 

[JimBolder]

Why you are using that much batteries? You can use a boost driver (you will need to design and build one) for that fan I think. Wire they in parallel or you will get VERY short runtimes for a labby...

I was originally going to run four (or three) in parallel, but I really had no idea how to power the fan.

I guess I can build a boost driver. Are they complicated? Again, I'm no electrical major.

 

[Trevor]

For my lab setup I'm using a converted ATX PSU - I use a 12V rail for a blower fan and a 5V rail to power the laser itself.

-Trevor

 

[Leodahsan]

@twhite
faster than me :cryyy:

but.. he wants to use 18650, don't he?

 

[JimBolder]

For my lab setup I'm using a converted ATX PSU - I use a 12V rail for a blower fan and a 5V rail to power the laser itself.

-Trevor

I actually have five PSUs just sitting around here. I guess I could do that, but can you regulate the current on those things?

 

[Trevor]

I actually have five PSUs just sitting around here. I guess I could do that, but can you regulate the current on those things?

I'd power a driver( like a Flexmod?) with the 5V rail, and let that regulate the current.

@Leodahsan - I thought I'd propose a slightly more practical approach for a lab build.

-Trevor

 

[Meatball]

I use wall warts. Some are regulated, some aren't. They're cheap, and take up little space.

 

[JimBolder]

I'd power a driver( like a Flexmod?) with the 5V rail, and let that regulate the current.

@Leodahsan - I thought I'd propose a slightly more practical approach for a lab build.

-Trevor

Ah, I see.

My original idea was to build the 4 batteries along with chargers into the host. That way, I could use it continuously plugged in at home, but it would become portable once I disconnected the power.

 

[Cyparagon]

Let's start at the beginning (See sig). Do you want it battery powered or line powered? Do you want it large or small? Do you want it high current or medium current? What is your budget?

 

[JimBolder]

Let's start at the beginning (See sig). Do you want it battery powered or line powered? Do you want it large or small? Do you want it high current or medium current? What is your budget?

1) Both. Line when plugged in, battery when not.

2) The host I'm thinking about using is ~170mmx100mmx65mm.

3) I'll be running a xja140 diode, so ~300mA-1800mA? Maybe? It's going to be my labbie, so I want a large range.

4) ~$100? I really don't have one set in stone.

 

[Leodahsan]

@JimBolder
giving your desired output (in mW) considering lens and heatsinking is better. 1800 amps (1kA) sounds kinda high for a 445, tho.

 

[JimBolder]

@JimBolder
giving your desired output (in mW) considering lens and heatsinking is better.

I don't have a meter yet (thinking about getting one in the near future), but ~threshold to ~2000mW (max).

Edit: NINJA EDIT

@JimBolder
1800 amps (1kA) sounds kinda high for a 445, tho.

1800mA. :V

 

[Leodahsan]

I'm just a little skeptic. Why you want a lab that powerful? What is your age and do you have appropriate protection ? :thinking:

 

[JimBolder]

I'm just a little skeptic. Why you want a lab that powerful? What is your age and do you have appropriate protection ? :thinking:

2 watts? It's not like I'm building a 100w CO2 burner or anything...

My age? What are you insinuating? I'm old enough. And I'm working full-time.

Appropriate protection? Who the hell builds a two watt laser without laser shades?

 

[Leodahsan]

I'm not insuating anything, don't be that defensive without a reason . I just don't want to my foreign (english) friends to be forbbiden to own lasers at all, because someone got "blinded" by a homemade unit.

A 100W CO2 wouldn't be THAT dangerous, as the PSU could literally "burn thru" you.
There are many people who don't understand the danger behind lasers, they don't know what 2W of blue light looks like.