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Old 12-05-2016, 01:09 PM
 
10,170 posts, read 10,501,652 times
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Personal heaters plug into USB ports are advertised as offering "200 Watts of warmth".

I am not sure how they get this much wattage as
Max. current
0.5 A (USB 2.0)
0.9 A (USB 3.0)

The current I in amps (A) is equal to the power P in watts (W) divided by the voltage V in volts (V):
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Old 12-05-2016, 01:43 PM
 
Location: Mount Laurel
4,169 posts, read 9,416,868 times
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Quote:
Originally Posted by PacoMartin View Post
Personal heaters plug into USB ports are advertised as offering "200 Watts of warmth".

I am not sure how they get this much wattage as
Max. current
0.5 A (USB 2.0)
0.9 A (USB 3.0)

The current I in amps (A) is equal to the power P in watts (W) divided by the voltage V in volts (V):

It's warmth.. not the amount of wattage.
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Old 12-05-2016, 05:50 PM
 
40,301 posts, read 41,850,213 times
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On USB3 it could be up to 20V and 5A for power delivery giving you 100watts, emphasis on up to. Does it come with two plugs?
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Old 12-05-2016, 05:58 PM
 
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Quote:
Originally Posted by sj08054 View Post
It's warmth.. not the amount of wattage.
Watts is a measurement of the amount of power you are drawing, if it was water think of it as gallons. It would specifically dictate the amount of heat it can produce.

Volts*Amps=Watts

3412 BTU's per kiloWatt-hour
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Old 12-05-2016, 07:05 PM
 
Location: Somewhere in northern Alabama
18,592 posts, read 55,510,434 times
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I don't often go out on a limb like this-

IDIOTIC

200 watts through a USB connector is like someone saying you can pee at firehose strength through your dick.
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Old 12-06-2016, 07:29 AM
 
2,909 posts, read 1,709,430 times
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Do people not recognize marketing hype when they see it?
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Old 12-06-2016, 07:46 AM
 
Location: East of Seattle since 1992, originally from SF Bay Area
30,885 posts, read 56,300,624 times
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Placebo effect. At my office, personal heaters that plug into AC are not allowed. If too cold, your only choice is the USB heater lap blanket. They are useless, according to those that tried them. While I find it a bit too warm at the setting of 70 they keep it at, others are working in coats. When you have 3 floors with 400 people there is no way to make everyone comfortable.
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Old 12-06-2016, 08:39 AM
 
40,301 posts, read 41,850,213 times
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Quote:
Originally Posted by harry chickpea View Post

200 watts through a USB connector is like someone saying you can pee at firehose strength through your dick.
The power wires are separate than the communication wires. For example on firewire a 4 pin connector/port common on DV cams do not carry power because they have their own power. Typically you have cord with 4 pin connector on one side and 6 pin on the other side because the six pin is common to the computer. The six pin connector on the cord is just dummy connection so the connector fits. Those two other pins on six pin port carry power.


I had to look this up but on USB that power wire is 20V and up to 5A so technically with two cords and a port supplying 5A you could do it.
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Old 12-06-2016, 08:48 AM
 
40,301 posts, read 41,850,213 times
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Quote:
Originally Posted by bigbear99 View Post
Do people not recognize marketing hype when they see it?
False or misleading advertising for electric heaters? What are you talking about?

The best is the specs on these 1500 watt heaters and they state "heats up to 2500 sq. ft." The keywords being "up to" meaning up to 2500 sq. ft. if you live in a house with terrific insulation, it's 69 degrees outside and you want to bring the temperature up 70.
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Old 12-06-2016, 12:46 PM
 
Location: Somewhere in northern Alabama
18,592 posts, read 55,510,434 times
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Quote:
Originally Posted by thecoalman View Post
The power wires are separate than the communication wires. For example on firewire a 4 pin connector/port common on DV cams do not carry power because they have their own power. Typically you have cord with 4 pin connector on one side and 6 pin on the other side because the six pin is common to the computer. The six pin connector on the cord is just dummy connection so the connector fits. Those two other pins on six pin port carry power.


I had to look this up but on USB that power wire is 20V and up to 5A so technically with two cords and a port supplying 5A you could do it.
OK, I'll see your two cord solution and raise you fifty cords to run a nice space heater.

The two cord solution assumes a power supply capable of cranking out full power on two plugs. Good luck with that. Then there is the age old issue of overheating connections and corrosion when you use a connector continuously at what is designed to be maximum wattage for a limited period.

Why am I even bothering? If someone wants to run a heater from their USB port, more power to them. When they then come around wondering why their power supply failed, their connector fell apart and they are still cold, I'll just shrug my shoulders and say "Gee, that is too bad" and walk peacefully away.
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