Did all go OK, or were those the "really wrong" circumstances?It turns out that given the right (or really wrong) circumstances, a buck converter can also work as a boost converter in reverse, providing a high voltage on what should have been the input.
So far max measured current was ~17A (at 22V) and max voltage 40V (0A), which is a bit higher than the 18-35V rating.
It's probably not so good for the converter and has no real use anyways since this specific converter is not adjustable.
Oh well... too bad that bidirectional dc-dc converters aren't a thing on ebay and such.
Putting a high load on the 12V rail such that it drops to 12.3V causes 40V to appear at the battery V+ rail.
Code:AC-DC ----------------------->|------------------------DC-ATX (12.6V) | | | | (out: 12.3V) BOOST BUCK CONVERTER CONVERTER | (out: 25.3V 1A) | (in: 18-35V rated) | | ------------------------------- | 40V when ac-dc at ~12.3V | BMS | 6S BATTERY (18-25.3V)
With stepping down, I just haven't found a converter which could handle high current for a more demanding rig. So far 3S 11.1V seems promising, just waiting for BMS to test the battery properly