I’m using thermoelectric generators along a heat source and will generate different voltages and milliamperes. I would like to step all out puts to a stable usable voltage. The TEGS will output from 4.8 volts and 690 milliamperes to 1 volt and 300 milliamperes. There will be at 3 TEGS and maybe up to 10 TEGS producing within these ranges or slightly lower. How do I get the maximum output from all the TEGS into a usable voltage.
What you are describing would be the equivalent of a combiner box in a solar system.
Your voltages are lower than most solar systems, so a suitable commercial combiner box might not be available. I’ll let you research that.
How does a combiner box work
The goal of the combiner is to enable multiple voltage source to live happily on the same bus. So I think the best way to do this in your case would be to give each Thermo unit a voltage regulator and diode that connect it to a power bus. But I will second Robins call to put in a bit of your own research first.