Parallel means that the voltage doesn't get divided. If you connect two 24v fans in parallel to a 19v charger, then both fans will get 19v. They might run a bit slow since the voltage will be lower than expected, but it'll be ok I think.
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my laptop charger which is rated for 19v to 24V
Well, feeding voltage in that range to 24V fans would be fine, but "19 to 24V" makes it sound like a USB type-C charger or something which communicates with the device to set its output voltage. A power supply should have a single voltage.
Unless it's one of those generic power supplies with a switch to set the voltage?
It's just a universal laptop charger. Should I get a regular power supply?
If it just puts out normal voltage it'll be fine.
I'd buy a cheap multimeter and test it for myself
Just get a boost converter. Cheap, like < $20. Your only worry would be amps, but fans can't draw enough to really concern yourself.
what would I connect it to for the power source?
I figured you already had some type of adapter already. Either the one you linked, or the DC connection from the printer. If that's the case, then it's ridiculously easy to do a DC to DC adapter. If you do not have a DC supply and just need a 24v power supply, splurge on something like this.
I just have my laptop one which I don;'t want to splice because well I use it for my laptop too lol
Would I be better off with that type of power supply?
Honestly you'd probably be fine with your original idea. But, that means you can't charge your laptop while printing and, the 24v power supply I linked to is cheaper than your original idea.
It's a spare laptop I use for random stuff, so I don't mind lol.
Those adapters should definitely be fine for 24 V. Running the fans off 19 V will probably work, but they will run at slightly slower RPM (probably not a big problem for a filter).
Yeah don't worry about it. Running a fan at a lower voltage than it's meant for will result in slower fan speeds and a longer lifetime. Compared to the wattage an actual laptop will draw this is absolutely nothing. I power my soldering iron with an old laptop charger without issues.
Those plugs are generally used in 12V systems but they can handle higher voltages too. It's the current you need to be mindful of for the most part, they can overheat if you try to power a space heater or something from that but a few fans won't cause any issues.