I think taht there is no step-up in this voltage class. Problem should be input voltage - 2,9V is really small to step-up to more than 5V. Yes,many these converters that has so low input steps only to 5V max. The cheapest way is to use step-up to 5V and second boost to 24V. That could be possible, but not with one boost converter.
Is it actually possible in a sense that can any converter provide a constant output over a large input range?
My plan is to use a DC to DC Step up Boost Converter to boost the variable input (i.e. 2.9V to 18V) to provide a 24V stable output for charging a super capacitor.?