I have a giant Sorenson (and several smaller older ones) lab PSU, and it's great for doing testing with, but it's huge and bulky, not transportable.
On the SB Cruiser trike itself, I use a single Meanwell HLG-600H-54A to charge my 14s2p 40Ah EIG NMC pack at about 12A. It's built into the trike; all I have to do is plug any extension cord from the trike's input jack to the wall, and off I go. I like them because they're sealed and fanless so will survive about any weather/riding conditions I'll encounter in Phoenix city riding. Been on there for...2 years? Can't remember for sure now. Survived one serious drenching that submerged that part of the trike completely (would've drowned any fan-cooled charger).
(it can also use either 220/240VAC or 110VAC, autoswitching, so if I had the right cord for that with me I could charge at any regular outlet--I don't carry a 220/240 cord because there are at least a handful of common types, but only one common 110/115 type)
I have three more of them that could be paralleled and/or seriesed to charge faster or to charge a higher voltage pack.
They don't adjust from zero to max voltage, but they do adjust from zero to max current. The voltage range is more than wide enough to deal with most battery pack charging, if you start with a model that is close to your pack's final charge voltage.