DC Motor connectivity in Series/Parallel confusion

Hello Experts,

I am trying to build one custom cooling pad for my gaming laptop. I have few computer/laptop fans(dc motors) as shown in the below and a DC power supply. I am a beginner, Please see the below details and let me know which motors I should connect Parallel and which are for series. My target is the motors should not blown out if I wrongly connected. The basic formula I know is if we connect anything in parallel, then the voltage is same and current is distributed and in case of series it's vice-versa.

DC supply - 19 volts, 3.33 A (I am using an old laptop charger as power supply)
DC Motors(Fans) -

DC motor1 - 12v 0.20A
DC motor2 - 12v 0.20A
DC motor3 - 12v 0.20A
DC motor4 - 24v 0.12A
DC motor5 - 12v 0.10A
DC motor6 - 12v 0.10A
DC motor7 - 12v 0.10A


If you proceed with connecting 19v to a 12v fan you will damage the fan.

These fans have built in controllers that require 12v.

Connecting motors in serie is normally not recommended.
However I do know it sometimes work if the fans have the same data. Two 0.20 Amp fans in serie as well as two 0.10 Amp fans could work. The 2 remaining fans, 0.10 and 0.20 will not fit in the picture.
It looks like You want to use surplus stuff, like found in a junk yard.

Don't connect them in series, that doesn't define the voltage - one fan may stop and the other run twice as fast (and perhaps burn out) if you try this, or it may sort of work with some fans - no way to tell as its not what they are designed for.

Give the 12V fans 12V, say using a LM2596 buck converter preset to 12V output.

Generally, connecting fans i serie is not recommended. However connecting two 220 volt fans i serie worked perfectly well, giving a reduced but sufficient airflow and a very low noise level.

Those would have been AC motors, not BLDC fans using Hall sensors and a control circuit to commutate - very different.

What makes You think Hall sensors and BLDC are involved?
Yes, 220 volt AC.

DC computer fans are all made this way.
[ I've dismantled quite a few... ]

Really? I've not opened "all" of them yet. Who knows how old they are?

Yes, computer fans that are DC powered use brushless sensored motors mounted direct on a small PCB. http://pcbheaven.com/wikipages/How_PC_Fans_Work/
You can dismantle them to re-oil the sleeve bearing to extend the life. typically you peel off the sticker, remove a circlip, extract the rotor and add a small amount of oil to the bushing, and replace.

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