Replying to myself for informational reason. Modifying voltage was more or less successful. Both optocouplers transmit a reference voltage, so both need to be adjusted simultaneously.
This can be done by changing the value of R19, a 23.2k smd resistor close to the output terminals.
I’ve attached a 10k pot with a 10k and 6.8k resistor in series and successfully modified the voltage down to 22.5.
The power supply itself is a piece of crap though. It claims to handle 400W but anything over 150W causes the short circuit protection to activate, never mind overheating at 150W very quickly.
Well there certainly is some regulation because attaching a load does not decrease the voltage by much. Increasing the voltage is indeed ambitious for the 12V model but lowering the voltage of the 12V model seems doable.
Thanks. I ordered the 24V model in hopes of adjusting it down to 22V. I will use that to keep a 7s Li-Ion battery at a minimum charge level whereas a solar panel array may increase that voltage higher. It looks like the 24V model’s capacitors need to be changed as well since they can’t handle the Li-Ion batterys’ max charge voltage.
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.