Sloppy nameplates

hillbilly1

Senior Member
Location
Atlanta,Ga
Had a tech concerned about voltage drop on a charging station, I had him send over a picture of the name plate.
100-240 volts 16 amps, really? 16 amps at what voltage? Second sloppy nameplate this week. BCBCC785-D1A7-4488-BB18-F29ED787B095.png
 

kwired

Electron manager
Location
NE Nebraska
Best guess is it draws no more than 16 amps when operating at 100 volts.

Keeping same power level would mean 8 amps at 200 volts.
 

hillbilly1

Senior Member
Location
Atlanta,Ga
Yep, switch mode power supply can operate over this large voltage range.

And a docking station would most likely have a switch mode power supply, like most computer equipment. Even if this does not dock a computer.
That doesn’t help figuring voltage drop, or even ocp. Should be in watts instead of having to assume 16 amps @100 volts.
 

Jraef

Moderator
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
That doesn’t help figuring voltage drop, or even ocp. Should be in watts instead of having to assume 16 amps @100 volts.
I agree. Too ambiguous. We can all agree on guessing what it MIGHT mean, but labels are not supposed to allow guessing. I'm surprised that UL allowed that, amkes me wonder if the UL listing is fake...

PS, no, it's legit, I checked on UL IQ

This is what their file says about marking though;
All power-supply types covered under this category are marked with input and output ratings that include the voltage and intended maximum load rating in amperes.
So I guess to the minimum letter of the requirement, it is marked with the voltage and INTENDED LOAD RATING in amperes. So I would take that to mean the OUTPUT is 16A maximum, regardless of the input voltage, which makes more sense, but is still lacking (lazy). I picked up my PC Power Supply and it tells me the DIFFERENCE between Input and Output ratings.

This is for a retail isle scanning robot, so most likely the batteries are 48VDC, at 16A = 768W, so even at 120V that's less than 7A. I wouldn't worry about VD on the feed to it.
 
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synchro

Senior Member
Location
Chicago, IL
Occupation
EE
Yep, switch mode power supply can operate over this large voltage range.

And a docking station would most likely have a switch mode power supply, like most computer equipment. Even if this does not dock a computer.
Yes, with a load like a battery that can accept a wide range of charging currents, a switched-mode power supply could be designed to draw a relatively constant current from an input over a 100-240VAC range. The battery charging current with 240V could then be as much as 240/100 = 2.4 times higher than at 100V. That way the charger could take full advantage of branch circuits that can supply 16A by reducing the charging time when higher supply voltages are available.
Or it could keep about the same output charging current over the 100-240V range, and then the maximum input current would go down below 16A as the input voltage is raised above 100V.
Or it could do something in the middle between these two modes of operation.

The labeling could certainly be more clear about this. I think you could use the 16A as a worst case in calculating the voltage drop. Then if the current goes down at higher supply voltages you'll just have a more conservative design.
 
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