Well, kinda. That thread had a link to this thread (which has a LOT of information):
But, getting back to your max capacity question - it really depends on a few of things:
- Is the container insulated
- Are you using pre-heated water
- What you’re filling it with
You can use much larger (very big camper coolers for e.g.) vessels when they’re insulated, provided you do your PC the HUGE favour of pre-filling it with hot water. You really don’t want to over-task your PC. These appliances are engineered for a range of uses over a reasonable life cycle. If you make it work too hard, you’re likely to shorten its life.
(also, taking a BIG camping cooler, getting it to temperature, then filling half of the volume with frozen pork chops…you get a notion for how bad an idea this would be??) 