It doesn't have any way to "know when to stop" or to auto turn off, so no it won't do that exactly.
But as long as it is set to a voltage the pack can tolerate without damage, then current will cease flowing because eventually the pack will reach the same voltage as the PSU.
However, that also means that topping off the pack will take longer than it mght witha smart scharger that "knows"when to slow and stop, because the dumb PSU will just follow the voltage/cell-resistance/current charge curve blindly, unable to raise or lower voltage automaticlaly to force the cells to charge at a constant rate up to the piont they need to not do that.
A smart charger can do that, and charge faster unattended, if it's correctly programmed for the type of cels the pack is made of.
Also, it's perhaps even more important to ensure the pack has a BMS if you use a dumb PSU because it can't detect a problem with the pack and shut off; the MBS has to do that.
A smart charger can (if it's programmed for it) stop charging if say, current goes back up after it was already dropping towards full charge (like if a cell went bad and shorted). A BMS would still be better in most of the cases like that, but sometimes just having a smart charger might prevent a fire-level pack failure.
I've done charging jsut about every way there is to do it...but I generally won't charge one unattended inside the house or near it, if it has no protections, unless it's contained in a fireprooof box (regardless of it's chemistry and type), even though I've had no unintentional fires during charging (there've been plenty of others to test those theories before me
).
