Use the recommended charger only
I discourage you from using anything else than what came with your respective laptop. It is not recommended to swap chargers for different laptops, even if it's the same brand. This is only 100% safe if it is the same brand and exactly the same laptop model. If you check your laptop manual, there should be at least one paragraph dedicated to explaining the risks of using a different charger. There should also be some mention about what charger models are recommended for your laptop model.
Charging with a power supply
It is possible to charge batteries with an adjustable power supply. But this is something that should be left to the professionals. You can't leave it unattended, as you have to observe the state of charge.
Reference: Charging with a Power Supply
Going Star Trek...
It would be ideal to use a professional, digital, programmable, DC power supply. This type of device is used for equipment testing, and as they are very advanced, precise and programmable, they can be used to charge any laptop you want (and more).
Here is an example of a Tektronix PWS4323:
This is obviously an overkill! It's not something for the average Joe. But for every problem, man has created a solution! Chances are that this little baby costs probably more than your laptop alone. MSRP: $904