I have a 30-panel 9k solar array on my home, plugged into a (now Generac) Pika grid-tied inverter system. I got the Pika unit because it appeared to be the best solution at the time, with array optimizers upstream of the inverter, and the (then projected) ability to add batteries to be off-grid.
Then Generac bought Pika and added batteries, BUT… the battery cabinet alone is $2000, and each 3kWh module is $2000. Plus, it’s not portable at all.
So instead I’m planning to get an AC2000Max for outages and portability, but in a SHTF scenario I’m hoping I can bypass the optimizers and feed a portion of my 9k array directly into the Bluetti unit. Can anyone comment on this approach? The system uses the standard solar connectors.
The problem you may have is the AC200MAX can accept a maximum of 145V DC from the solar panels.
I do not know your voltage but I know large rooftop system can sometimes me upwards of 1000V … that will let the smoke out of the AC200MAX 
So - a few options. Can you spit the array to use only some of the panels? Otherwise there is a step down convertor you can use.
BTW - the B300 battery is 3kWh and is ~$2700CAD so it seems similar to the price of the Generac, although the B300 is much more portable (although heavy).
I figured I would have to go up into the attic in a SHTF scenario and run separate lines at lower voltage (I think the optimizers are somewhere around 450v).
And the price of the batteries for the generac unit aren’t bad, around $1900 for 3kWh, but I still have to pay $2000 for the cabinet, and it’s not portable at all.
Yep, just checked, NOMINAL OUTPUT (REBUS™) 380 VDC