USB-C Cables....

[SimonMac]

I’ve seen a really good summary of the data transfer speeds between the various types of USB-C standards (Gen 1/Gen 2, Thunderbird 3 etc), but nothing in terms of charging speed.

I understand that the power block in the fall would be a major factor, and I have plugs from 18W to 61W and the higher the rating the faster the charging (or more power drawn) but does the cable used between the plug and device being charged matter?

[eek]

USB Type C Power Delivery Profile - max length? - Super User

[Lance]

I’ve seen a really good summary of the data transfer speeds between the various types of USB-C standards (Gen 1/Gen 2, Thunderbird 3 etc), but nothing in terms of charging speed.

I understand that the power block in the fall would be a major factor, and I have plugs from 18W to 61W and the higher the rating the faster the charging (or more power drawn) but does the cable used between the plug and device being charged matter?

The cable will need to be rated for the current draw.
Googling this "usb-c charging voltage" give a nice table.
So the cable needs to be able to 5A max. And at 20V that is 100W so bigger than your PSU.

USB 3.0 and USB 3.1	5 V	900 mA
USB BC 1.2	5 V	1.5 A
USB Type-C 1.2	5 V	3 A
USB PD 3.0	20 V	5 A

[SimonMac]

The cable will need to be rated for the current draw.
Googling this "usb-c charging voltage" give a nice table.
So the cable needs to be able to 5A max. And at 20V that is 100W so bigger than your PSU.

USB 3.0 and USB 3.1	5 V	900 mA
USB BC 1.2	5 V	1.5 A
USB Type-C 1.2	5 V	3 A
USB PD 3.0	20 V	5 A

So is it as simple as multiplying the V and the A to get the W?

[northernladuk]

So is it as simple as multiplying the V and the A to get the W?

Here you go....

Watt's Law (P = VI)


Calculating the power dissipated by a circuit element is simple. Often much of this power is converted into heat, so by thinking about the power dissipated by circuit elements, you can make sure that they don't burn up or catch on fire! (When a musical instrument catches on fire, the way in which the performer interacts with it usually changes.)

Watt's Law states that: Power (in Watts) = Voltage (in Volts) x Current (in Amps) P = V I Combining with Ohm's law we get two other useful forms: P = V*V / R and P = I*I*R Power is a measurement of the amount of work that can be done with the circuit, such as turning a motor or lighiting a light bulb. Consider a 100Watt light bulb in your home. We know the voltage applied to the bulb is normally 110V or 220V so we can calculate the current consumed as follows: I = P/V = 100W / 110V = 0.91 Amps or I = P/V = 100W / 220V = 0.45 Amps So you can see why using a 60W light buld is more economical. Your electric company normally charges you for your usage in Killo-Watt Hours (kWh). One kWh is the amount of energy necessary to do 1000 Watts of energy for one hour - in other words to keep 10 100W light bulbs shining for one hour.

You can go through the house calculating how inefficient your lighting is now

[Lance]

Here you go....



You can go through the house calculating how inefficient your lighting is now

well. Can you?
You can do a calculation of how many watts per lumen, and that gives you a broad idea of the 'efficiency'. But I have a problem with those sort of calculations.
I live in the north, and heat my house, so any light bulb is 100% efficient unless it makes audible noise. The 'inefficiency' of lightbulbs is the heat generated but that's not 'waste' for 9 months of the year.

[MPwannadecentincome]

I have a laptop that charges via USB-C - I have a phone that also charges via USB-C.... No I don't get the cables mixed up... and haven't plugged the charging cable into the USB-C port ... even though they are next to each other on the laptop. I presume some sort of protection is built in to prevent damage? I would hope so, though I am not doing any experiments to see.

[northernladuk]

I have a laptop that charges via USB-C - I have a phone that also charges via USB-C.... No I don't get the cables mixed up... and haven't plugged the charging cable into the USB-C port ... even though they are next to each other on the laptop. I presume some sort of protection is built in to prevent damage? I would hope so, though I am not doing any experiments to see.

Yeah. USB-C talks to it's host unlike previous cables so it will recognise a power charger or not. They are smarter than plugging the wrong one in.

THE USB-C POWER DELIVERY CHIPSET DELIVERS EXACT POWER REQUIRED

Whether it’s a small phone or a large laptop, the USB-C PD charger detects the connected device to deliver the right amount of power to charge that device as fast as possible. This ensures fast charging without delivering too much power which could damage circuitry.

So no need for separate cables for phone or laptop. The devices will detect it and charge in the correct way quite happily.

What I do do with USB C's that I didn't so much with other cables is buy decent ones. The speed and power delivery of the old USB's was affected by the quality of the cable. I had some cables that would take hours and hours to charge a devices (These were usually the free ones you get with gadgets) where as a decent quality one would do it in a fraction of the time. Knowing this I got a bit tetchy about what cable to use so ended up having to hunt certain ones out and chuck the others.

I tend to only buy recognised branded ones now which cost a bit more rather than any old thing for a couple of quid off Amazon. If it is supposed to be smart and it needs to be completely interchangeable I'd rather know I've got a proper cable. If poor quality ones affected charging so much before I'll be buggered if I'm going cheap on a cable that can deliver 3A to my laptop. I might be being over cautions but if the electronics in the cable are as crap as some of the cables out there I'll not take my chances.

[northernladuk]

well. Can you?
You can do a calculation of how many watts per lumen, and that gives you a broad idea of the 'efficiency'. But I have a problem with those sort of calculations.
I live in the north, and heat my house, so any light bulb is 100% efficient unless it makes audible noise. The 'inefficiency' of lightbulbs is the heat generated but that's not 'waste' for 9 months of the year.

I was meaning halgoens vs LED's. I did the numbers on the 80+ halogen spots that were in my house vs the LEDs I put in which as very satisfying. And IMO the LEDS I've got give a nicer light than the Halogens.

[Lance]

I was meaning halgoens vs LED's. I did the numbers on the 80+ halogen spots that were in my house vs the LEDs I put in which as very satisfying. And IMO the LEDS I've got give a nicer light than the Halogens.

LEDs are the future. Isn't quantum mechanics great?