Home Built UBEC

[BrianG]

And you generally don't parallel regulators, but use a higher power/current pass transistor. But no matter how it's done, a linear regulator is inefficient, especially as the supply voltage and load current increases.

That said, a linear regulator works well in the 2s (maybe even 3s) or 6-8 NiMH cell range. Since the voltage is so low, efficiency is close to a switching UBEC.