"I've got a 60W 12V incandescent bulb I used to light a shed, powered by a rechargeable boat battery. When I hooked it up to check sag the Meanwell (I'm gonna write it like you and save keystrokes) stayed pretty tight. "

Incandescent are kind of self-limiting.
Hotter filament = higher resistance.
Just the opposite of emitter junctions which draw more current as they get hotter.
Thermal runaway happens fast too!

A 10 ohm 20W. resistor will draw 1.2A at 12V. and is linear, thus mo' betta for checking sag.
if you switch a 100 ohm resistor parallel to the 10 ohm you can have an almost instant 10% load change.

Tip:

Switch that Fluke to AC and hang it on the meanwell output while changing the load.
Should still read zero = (no change in DC level.)

A triggered 'scope will give you more detail than you need, but a simple AC meter on a DC source will sometimes find gremlins like ripple, spikes, oscillation or induced RF.
Has saved me much grief.

We now must pause for a pidgin moment.

"All kine sing get in dere.
Den LED get all buss' up"!:rastasmoke:

OK, now I'm over it.

Proper english grammar can be quite inefficient, ya?

Pidgin is a lazy guy's friend.:thumbsup:

If it's not clear at times, don't hesitate to ask what the hell I'm on about.

'loha
Haole boi