The MM flight batteries are rated to be able to be charged at up to a 24W rate, however the DJI wall charger provides just ~18W.
I've tested a 36W dual QC 3.0 car charger and also found the most one port would provide was 18W also.
I then saw a 48W dual QC 3.0 car charger advertised by LMAV, so this video shows what I found using it.

One new discovery I made is what the HUB's USB-A port's maximum capability is in Amps and Watts.

The MM flight batteries are rated to be able to be charged at up to a 24W rate, however the DJI wall charger provides just ~18W.
I've tested a 36W dual QC 3.0 car charger and also found the most one port would provide was 18W also.
I then saw a 48W dual QC 3.0 car charger advertised by LMAV, so this video shows what I found using it.

One new discovery I made is what the HUB's USB-A port's maximum capability is in Amps and Watts.