Extra <span class="highlight">solar</span> panels

Hello Watto.
For replies to be focussed and more accurate it may be best if you reveal what the system is, how much Solar input you can push into the regulator, it's AMX input voltage, size of battery storage and the use you demand from it. Then people can give realistic replies which are meaningful for you. YES, you can add larger or more panels but it should be done to ensure it solves the problem you think you have.

Solar panels can be wired in parallel or series, depending on regulator ability and specs. Read wattage max input and voltage max input. Rarely does a 200w "stated" panel achieve anywhere near it's claimed output, so really you are working with much less delivered to battery. Wiring sizes also have a distinct effect on the total power harvest.
Give us the info then see what is possible.

Check how many amps your regulator is rated at.

Yes you can add extra panels with the main restriction being the solar regulator capacity.
When I first started 20 odd years ago, I had a single 60w panel and it did the job.
Now I have 600w and it's still not enough for me. I still use way too much energy.

For cheaper panels to have a chance of getting to 200 watts in perfect conditions it would need to be about 1.3 square metres in cell surface area.