Considering with only one mirrorless camera and one DSLR I have to lug around 10+ batteries in my camera bag...yeah. Running out of batteries at a wedding isn'

Considering with only one mirrorless camera and one DSLR I have to lug around 10+ batteries in my camera bag...yeah. Running out of batteries at a wedding isn't an option. Plus I keep backups just in case my camera bag is stolen, and first party Nikon batteries are $70 per. I hadn't considered keeping a battery bank and a long USB-C cable as a backup though, so I'll need to look into that.