got 4 Panels, 410wp each. Correct voltage range, etc.
What happens if they deliver about 1200w to the AC200max ?
Any harm or over 900w just wasted ?
If the open circuit voltage is still within the AC200MAX range after connecting the solar panels in series, there is no problem. The machine is limited to a maximum of 900W PV input, and any excess will be wasted.
Would not the DC Charging Enhancer (D050S), but kinda of expensive $$, allow to use more solar power, to not waste power beyond 900 Watts allowed via the Solar Port ! 
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yes you can use the charge enhancer with one of your 410 panels. you can plug into the ac200max wall charger port. you can also buy another charge enhancer and use it in the b230 battery ac charge port.for maximum charging. I one charge enhancer and thinking of buying a second one to do that. I use 430 watt solar panels. so that I can maximize in cloudy days and hit maximum on sunny days. as long as you keep the voltage and amps within specs the unit ignores the extra wattage.
will Prowse on YouTube has great reviews on bluetti products and other solar stuff. that’s where I learnt most of what I knew before buying Bluetti products.