Something like 12V down to 5V at 5A creates a managable amount of heat, but going higher, 20V, 30V on the battery side and things start to melt all around from heat losses from that large a drop. In some cases I've had to resort to using cascaded rails, stepping first down to 24, then 24 to 12 and then 12 to 5 just to keep the heating spread between different buck converters even if it multiplies losses. Would love to hear what the expert solution is to this that isn't just a massive heatsink.