How about getting a portable induction stove that shows it’s power in Watts. Then you can just stay under that level when you are on a limited supply.
Note that not all display power in watts, and many cheap units tend to taper the power down to a modest level (from memory about 600 Watts on the new ikea model) then pulse on and off to do lower power levels, which is annoying doing absorption rice in pans with a low thermal mass for example.
