One problem with adjustable power supplies is that most are NOT designed to be battery chargers!
When the supply sees the low IR of a battery bank, it can be mis-detected as a short, and the power-supply CROWBAR circuit kicks in. The "crowbar" circuit is so-called because it acts like placing a direct short on the output in order to force the supply to shut down internally and not provide any current. In many cases, the crowbar just fries. It's a simplistic protection, but the secondary effect of a fried crowbar or other circuitry is not kind to batteries who now see a failed power supply as a load!
en.wikipedia.org
So the one "trick" to prevent this from happening was when first setting up your lab-supply, make sure you turn up the current a little bit, and then adjust your voltage with a reliable meter. THEN make your connection to the battery and NEVER adjust the voltage again during charge. If your current pot isn't turned up a little bit, it may not be enough to FOOL the crowbar circuit that there isn't a short masquerading as a discharged battery on the other end.
Turning the current pot up a bit PRIOR to attaching to the battery, can sometimes help prevent the crowbar from kicking in. But of course be careful!
Some adjustable lab-supplies will actually state that they are suitable for charging, but of course they cost more.
Ie, if you can initially adjust your lab supply voltage, but your current pot is at the dead end of rotation, nudge it just a little to get it off the stop and cross fingers that this will be enough to fool the crowbar.