I don't think you get what he
I don't think you get what he was saying exactly. They fully load the trailer volume with Frito lay chips, but it's still 45,000lbs net which is about normal max for a regular semi with a 48' trailer. And for Pepsi, yes it's very heavy, so for the same 45,000lbs trailer loading you won't be double stacking pallets and not fully cubing out the trailer like the chips. No diesel semi can be fully loaded with soda either as you max out the weight pretty quickly. It's still gonna be about 45,000lbs.
Given that they're able to carry 45,000lbs, which again on a normal diesel semi typically gets you to the max legal weight give or take 4,000lbs for a 2 axel 48' trailer. They aren't limited here by battery weight, nor is the 500 mile range some light load, but seems to be as stated at a bit over 80,000lbs gross they get 500 miles.