I currently run 2 inverters in my tiny house, 1 2000w for lighting and plugs (as a backup in case grid goes down), with transfer switch and use Bluetti B1232 battery.
And a 2nd inverter 3000w inverter charger with 400Ah capacity, for larger cooking appliances,
I purchased the D40 to use with my AC200L, incase for quick charging, so I was able to hookup the D40 with anderson conectors, in a way to charge from Bluetti battery to the other bank, and visa versa,
my Solar is hooked up to the 400Ah bank, so when my bluetti B1232 needs a charge, I input from the 400Ah bank, to D40 PV/engine input, and DC output to the B1232, from 30% it takes approx 14 hrs.