Maximum wattage I can expect to suck from the coffee shop?

If I were to travel cross country with a power supply looking for outlets along the way what can I expect? I found an outlet at the Golden Gate Bridge couple days ago when I saw someone charging their one wheel on it. I feel like every library or somewhere should have a public outlet. Not that I think they do but wishing. My 600 watt meanwell on a rack wouldn’t be bad (on the back sucks). If there’s a lighter option please link it.

Hummina Shadeeba said:

Maximum wattage I can expect to suck from the coffee shop?

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If you can see all the outlets (i.e. it's a string of outlets for patrons) then it is probably on its own circuit and you could pretty safely go to 1200 watts (10 amps) as long as there aren't a dozen huge laptops on the same string.

For a hidden outlet behind a plant I wouldn't go more than 500 (about 4 amps.)

Depends completely on what the circuit was intended for, and how many amp loads are running on the other outlets on that circuit.

If it's a dedicated circuit for big powerful cleaning machines, only used after hours might even be safe pulling 20A.

If they ran courtesy outlets off the circuits already in place for the coffee gear, you might blow out the CB at only a few amps AC.

A charger that lets you scale the current pulled up or down would be nearly essential in that scenario, e. g. Grin Satiator, or a Hobby balancing charger. Better than carrying multiple PSUs around anyway.

As mentioned, a 'standard' circuit would be 15 amps (1800 watts) a 'high current' circuit would be 20 amps (2400 watts). Ideally those would be indicated by the outlet. The 15 amp outlet has two vertical slots and the round ground pin, while the 20 amp has an additional horizontal notch in the left-hand vertical slot. Though a lot of times, you see the 15A outlet on a 20A circuit... and sometimes the reverse, too!

Technically, either of those two wattages are de-rated to 80% for 'long term' use, so figure that in if you expect to charge for a while. Many places also won't have a full 120 volts...often sagging to 115 or lower - so that also cuts into wattage. It would also depends how many other people are on that same circuit - which may or may not be obvious. As mentioned, 10 people plugged into a strip at a table, might be already using most available current. A lone outlet somewhere may have almost all available current... unless it's also on the same circuit as the table!

Guess one way to know for sure is to keep drawing more and more current until the breaker pops, have them reset it (hopefully they know where and how!), then draw slightly less current from there on!

15A (though sometimes on a 20A circuit)


20A (though sometimes on a 15A circuit!)

Popping a breaker in a busy shop is very likely to attract unwanted attention.

A very stealth setup that looks like you're powering just a normal notebook or phone charger would be a good idea