USB DoubleCharger Is it BS?

[ccs46]

So I was just looking through kick starter and I came across this: https://www.kickstarter.com/projects/1599478765/usb-chargedoubler-double-your-charging-speed

I'm not so sure about this thing. It's made in Germany and I have been told the Germans make good quality stuff. But as I have seen from Dave's videos, shit quality stuff can be made anywhere. Now I am OK with electronics (I always keep a ABC fire extinguisher handy.  ) but I don't have a degree in electronics unlike Dave or others here. I know Dave has a busy schedule so I know he might not be able to do it.(It would be great to hear him rant about this device.) So maybe someone else can do some investigating so people can know about this thing. 3,397 backers pledged €59,453 so maybe it might work. For some reason it just seems like BS. I mean could it charge my iPhone faster than my default charger? I know my iPad charger can charge it faster than the standard iPhone charger.

If anyone has insight to how this works or whether it really is as Dave would say: "A steaming pile of dog turd!"?

[XOIIO]

Oh god, wasn't there one of these stupid "Fast charge" cables a while ago?

[rs20]

I can't be bothered reading the thing through, but I'm guessing the idea is that when connected to a computer, the charging is limited to 500mA or so; when connected to a "real" USB charger (which has its D- and D+ lines shorted), they'll charge at 1A or more.

So if you make a cable that passes through V+ and GND from the charger, and just short D- to D+ on the phone, and plug it into a computer with a strong +5V supply, it will genuinely double your charging speed or more. But it's a) completely breaking the USB spec, and b) the phone will only be charging as fast as it normally would with a normal phone charger with a normal cable.

Nevertheless, I have a cable just like this at home, my computer can take it and it's more convenient and power-efficient that using a dedicated charger. The important thing is, though, that (perhaps unlike the backers on this campaign,) I understand that it's no faster than just using a proper charger. 

[Wilksey]

Essentially it states just that, that it supplies 1A rather than 0.5A, so they got awarded nearly €60k for a resistor or two 

Though, you can't guarantee that a USB port will be capable of supplying 1A, it might damage some as it is outside of the USB specification, bit like buying a 100mA regulator and expecting it to be OK when you try and draw 500mA from it, chances are it will survive, but if it's not rated for such power what is it doing inside.

Meh, just a thought on these "fast" USB chargers, it's ok if you are plugging into a USB plug pack capable of delivering over 1A, but a Laptop? Not convinced.

[Jeroen3]

Much like this thing.
http://www.delock.de/produkte/S_65241/merkmale.html
Which is around sine the iPad was first introduced.

[Halcyon]

Meh, just a thought on these "fast" USB chargers, it's ok if you are plugging into a USB plug pack capable of delivering over 1A, but a Laptop? Not convinced.

I'm pretty certain my HP supplies 1A output. Even if it didn't the USB controller will only supply the maximum it's capable of and warn you about it through the OS. Most decent laptops these days will have at least one "high power" or charging output which will supply power even when the system is powered off (through a BIOS setting).

[george graves]

I was under the impression that apple devise won't even try to take 1 amp if the D+ and D- lines are shorted.

[rs20]

I was under the impression that apple devise won't even try to take 1 amp if the D+ and D- lines are shorted.

Yeah, Apple devices use a combination of analog voltages on the D- and D+ lines, as opposed to the standardized shorting of the D-/D+ lines. The "chip" that is mentioned in the kickstarter in question is probably just one of these chips that figures out what the device wants: D-/D+ shorted, 2.7V on D- and 2V on D+, etc, etc.

EDIT: Specifically, the TPS2511 (datasheet link) or similar.

[Wilksey]

Yes, most modern devices do, 3G dongles use more than the 500mA power, some can use over 800mA, and they seem to work OK for most things, but it's not guaranteed.

I wasn't aware that high power USB charging was still a "hot topic", especially on places like KickStarter!

[suicidaleggroll]

Again?
https://www.eevblog.com/forum/crowd-funded-projects/magic-cable/

[tom66]

Maybe the next thing will be sticking a boost converter on the USB end to compensate for the cable voltage drop.
 

[XOIIO]

Again?
https://www.eevblog.com/forum/crowd-funded-projects/magic-cable/

Yeah that's the one.