Advice sought on why 6.8A USB charger melted USB cable today

it's been explained several times.

then you should be aware that there cannot be smarts in the charger. it's a +5vdc power source.

no.

no it won't. it has a dedicated 'superport' with 2a and the rest are 1a.

nope.

stop twisting and lying. it's really obnoxious.

nope. the specs said there's one superport.

two will get 1a.

regardless, there are no smarts in the charger for eoc detection. it just supplies power. the smarts and eoc detection are in the device and/or battery.

Reply to
nospam
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not really and it doesn't work the way you think it does either.

yep.

a smart charger means it intelligently charges a battery by constantly monitoring its state of charge and changing the charge strategy as needed. usb chargers do *not* do that.

Reply to
nospam

Yep. The real question here is ... is this a good idea ? :) Car makers say yes (cos you can't service them yourself without some serious diagnostic kit).

The more things included, the higher the risk that something breaks. Personally, I hate air con in cars ... but the number *without* this "feature" is now vanishingly small.

Reply to
Bruce Sinclair

nospam wrote, on Mon, 07 Dec 2015 19:12:07 -0500:

There are two so-called 'superports'. And they float to any two ports. Why can't you see this?

You are right though, that the eoc isn't detected by the charger.

The sink current is detected, and that floats the two superports. That's the smart part.

It doesn't detect EOC. That's the dumb part.

Reply to
Danny D.

You are wrong.

The 'reroute' power is the 'smart' part of the charger. Most USB chargers only supply 1amp to the USB port. Some chargers supply 2.1 amps. However, supplying 2.1amps to 6 ports is a LOT of power, so most chargers will designate one or two 2.1Amp ports.

This charger (and a lot of newer chargers) have some smarts that allow them to route those two amps to whichever ports need them. In this case, up to three ports.

This rerouting of which ports can provide 2amps has nothing to do with the complicated software on the devices and batteries.

Reply to
Lewis

Lewis wrote, on Tue, 08 Dec 2015 13:57:35 +0000:

I do understand that the "smarts" in the charger is simply for re-routing the "superport" to up to three ports.

The "dumb" part of the charger is that it does not sense the EOC of the battery. Those smarts are in the device/battery circuitry itself.

Reply to
Danny D.

that's minor.

there's no way for that to happen with a usb charger.

Reply to
nospam

Yes, of course. We've all been using (relatively) dumb chargers for years so it's pretty obvious that a wall-wart doesn't *need* to have the smarts of a 128k Mac!

The point was being made (by Bruce Sinclair, to whom I was replying) that modern chargers do have some smarts, and I thought it might be interesting to give an example (as I'd just come across it recently and had the link to hand) of a charger with a very great deal more smarts than one might imagine.

It *is* slightly boggling just how smart a charger can be, while remaining roughly plug-sized.

Indeed, but threads drift ... it would be a dull world if they didn't.

Reply to
Daniel James

it doesn't.

some do, but not for charging strategies.

the magsafe adapter example you cited is for magsafe communication so that the laptop knows how much power is available.

for usb chargers, that's done over usb.

it doesn't communicate soc or eoc. that's in the device itself and/or the battery.

not really. there are much smaller products that are quite a bit smarter than any charger.

Reply to
nospam

nonsense. 1 amp through a coiled usb cable is not going to heat up. they even make coiled usb cables.

Reply to
nospam

Correction - I never made that point. :) (snip)

Reply to
Bruce Sinclair

Yep. If you don't know this, you work it out when you plug in a coiled cable for a while and it gets hot. :) Power cables on rolls have always come with the 'completely unroll before using' (or similar) instructions. :)

Reply to
Bruce Sinclair

Not in this case. Read the Amazon wording carefully - "Sold by Brand Sale USA and Fulfilled by Amazon."

The phrase "fulfilled by" means that in law, Amazon is not the seller. Amazon handles the logistics, that's all. In Europe it's a popular way of getting round all kinds of legalities, in particular VAT and warranty claims.

Reply to
Tom P

No, I don't think it necessarily is, it just rather vaguely says "Maximum power: 40W" on a separate line without any real clue as to what it refers to.

In my experience many Chinese manufacturers wouldn't care about the legality of giving a slightly wrong number. Many lie outright about meeting safety standards.

Reply to
Brian Gregory

They could give specify VA, watts or both. Whatever they felt like putting in the spec. The VA figure can be higher than the wattage if the current draw in from the mains supply isn't in phase with the voltage.

Reply to
Brian Gregory

But this isn't really a battery charger. That's just what you use it for

- it's actually a power supply with USB output connectors. It just has to give out 5V at as much current as what ever is connected wants. Ideally it needs the ability to tell what you connect to it how much current is available so that devices can decide to fast charge if they want to without fear of overloading it. It's up to the device to protect it's battery from over charging.

Reply to
Brian Gregory

The who gives a flying f*** about a slightly wrong largely irrelevant largely unexplained figure in a technical specification department of the FBI?

Reply to
Brian Gregory

But they don't really even tell you what it is.

It doesn't say "Maximum output wattage".

Reply to
Brian Gregory

It could be the input power.

VA is if you measure the RMS input voltage and then separately measure the RMS input current and multiply them.

But depending on what is inside the charger the voltage and current may not be in phase so the power, in watts, drawn from the mains might be less than the VA value.

Reply to
Brian Gregory

So typical of the Chinese not to pay for their copy for Fineprint pdffactory!

You think they'd care about making sure every figure in the spec is exactly right?

No.

Reply to
Brian Gregory

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