In article , Daniel James
wrote:

the smartness in that charger is for communicating with the laptop
about the adapter's capabilities, not charging strategies, which is
handled by the macbook based on the reported capabilities.

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!

it doesn't.

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.

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.

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

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

In article , Daniel James
wrote:
In article , Nospam wrote:

in any event, the thread is about a usb charger which doesn't do
any of that.

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

I missed the start of this topic, but I don't know if anyone suggested
the cause of the cable meltdown as being the possibility that the cable
was coiled / bundled. Coiled / bundled cables can potentially over
heat, whether it's a USB charger cable or a wall power cable. The
cables should always be a spread out as possible.

In article , Your Name
wrote:

I missed the start of this topic, but I don't know if anyone suggested
the cause of the cable meltdown as being the possibility that the cable
was coiled / bundled. Coiled / bundled cables can potentially over
heat, whether it's a USB charger cable or a wall power cable. The
cables should always be a spread out as possible.

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

In article , Daniel James wrote:
In article , Nospam wrote:
the smartness in that charger is for communicating with the laptop
about the adapter's capabilities, not charging strategies, which is
handled by the macbook based on the reported capabilities.

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,

Correction - I never made that point.
(snip)

In article , Your Name wrote:
In article , Daniel James
wrote:
In article , Nospam wrote:

in any event, the thread is about a usb charger which doesn't do
any of that.

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

I missed the start of this topic, but I don't know if anyone suggested
the cause of the cable meltdown as being the possibility that the cable
was coiled / bundled. Coiled / bundled cables can potentially over
heat, whether it's a USB charger cable or a wall power cable. The
cables should always be a spread out as possible.

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.

On 12/02/2015 11:32 AM, wrote:
nospam wrote:
but the odds are much better that you will get a safe, quality product.
The off-brand products tend to be made in little sweatshops, people's
kitchens, wherever, without the benefit of engineering knowledge or QC.

not only that, but with a name brand, you get a company to go to if
something does go wrong.

with a noname brand, you're screwed, and the magnitude of the problems
are bigger. see my other post for just how ****ty a noname charger can
actually be.

In the UK (and Europe in the main) your claim if something doesn't
work or isn't to specification is against the seller. You have no
rights against the manufacturer unless you bought it direct from them
(though in some cases they *may* offer service). Thus it doesn't
matter at all if something is branded or not, you still have a claim
against the seller.


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.

On 30/11/2015 17:55, Danny D. wrote:
Scott Lurndal wrote, on Mon, 30 Nov 2015 17:38:04 +0000:

Q1: Since 6.8A times 5VDC is only 34Watts (not 40 Watts), how
can they very clearly label it as a 40Watt device?

http://www.powerstream.com/VA-Watts.htm

Here is a better (bigger) picture of the unit:
https://i.imgur.com/8bl7ypU.jpg
And a better (bigger) picture of the package:
https://i.imgur.com/30qxupn.jpg

I thank you for the reference, but, after reading it, I don't
see how that article helps explain the *output* wattage
descrepancy between 6.8A x 5VDC and the stated output spec
of 40Watts.

That article explains how to convert Volt-Amps to Watts.
"How to convert VA to Watts and KVA to Kilowatts"
http://www.powerstream.com/VA-Watts.htm

The input voltage is AC so roughly the input wattage is:
110VAC RMS times 800mA (max) which is roughly 88VA

But it's the OUTPUT wattage that is stated to be 40Watts.
6.8Amps x 5.0VDC is only 34 Watts

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.


Hence, a rather large 15% descrepancy (6 watts less than
40 watts).

I'm sure my math on the output wattage is wrong because
the package can't be wrong (that would be illegal), so,

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.


I don't see where my math went wrong yet though.

So, any advice is welcome and I will check it out.


--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

On 30/11/2015 19:46, Danny D. wrote:
Bob F wrote, on Mon, 30 Nov 2015 11:43:06 -0800:

It looks to me like it says "maximum power" 40 w.
It doess not say that is output power.

This is true that the package says "maximum power 40W"
which "could" be input power (but nobody cares about
input power - so why would they list it)?
https://i.imgur.com/30qxupn.jpg

The unit says the input is 100-240V at 800mA maximum,
but that doesn't calculate anywhere near 40 Watts.
https://i.imgur.com/8bl7ypU.jpg

100 volts (RMS) times 800mA is about 80 VA (aka Watts).

So, if the 40 Watts is input power, it's under reported
by 50% at 80 Watts actual.

If the 40 Watts is output power, it's over reported
by 15% at 34 Watts actual.

I don't think it's input wattage though, because that
would be reported in volt-amperes anyway (VA).


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.

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

On 01/12/2015 02:41, Tony Hwang wrote:
Danny D. wrote:
Tony Hwang wrote, on Mon, 30 Nov 2015 18:00:22 -0700:

We have couple iPADs kicking around in the house. I wouldn't use
quality unknown anything with iPAD for the danger of damaging the unit.
Look for UL, CSA,EU approval Logo on stuffs like that. I have O'scope
at least I'd check how clean output they produce EU standard is quite
higher than that of UL.

They print the UL approval on lighting cables?

Good charger is not just putting out certain voltage. Ihas some smarts
and as charging progresses it tapers back the current. Regulating output
current. El Cheapo charger may charge a device but it can shorten
the lie of battery or damage the device. Spend some money and buy some
decent product.

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.

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

On 01/12/2015 01:01, Danny D. wrote:
Tony Hwang wrote, on Mon, 30 Nov 2015 17:52:11 -0700:

If you understand inductive or capacitive reactance in AC circuit.

I think the packaging is telling a lie about the 40Watts.

If you look at the device, you see the model of HC363-5U.
https://i.imgur.com/8bl7ypU.jpg

If you type "?HC363-5U" into the URL bar, you find the same device
under a different brand name, which lists it clearly as 35 watts!

amazon.com/Hausbell-35W-HC363-5U-Certified-Family-Sized/dp/B00NUREFMO

So, pretty much, I think it's a lie or a "misprint" that the unit
is 40Watts. It's more like 34Watts (35W is reasonably close).

"Hausbell 35W HC363-5U UL Certified (UL No:E310745)
Family-Sized USB Wall Charger Plug Smart Charger,
Single USB Output 2.4A Max,Output total 6.8A Max,
5P-USB Output for Apple and Android Smartphones,Tablets and More(White)"

Do you know which authorities to contact?


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

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

On 01/12/2015 09:32, Danny D. wrote:
Bruce Sinclair wrote, on Tue, 01 Dec 2015 03:38:14 +0000:

And the difference between 35 and 40 W is so small as to be irrelevant too I
suggest.

You've got to be kidding.
It's huge the difference.

15% is a huge lie on something so simple to calculate.


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

It doesn't say "Maximum output wattage".

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

On 01/12/2015 00:30, Danny D. wrote:
Danny D. wrote, on Tue, 01 Dec 2015 00:20:57 +0000:

The voltage and current fluctuate so, even if you pick the
RMS voltage and current of the one AC signal, if you try to
add it to another AC signal with a different phase, then
you have to factor in the power factor.

This article says the AC power factor plays a role whenever the
AC current and the AC voltage are not in phase:
https://en.wikipedia.org/wiki/Power_factor

I think the whole power factor thing is a red herring because
we're talking output power, which is DC, which has both the
current and voltage in phase.

Only if the 40W is for the input power would the AC power factor
matter, and, if that 40W was for the input, it wouldn't be called
Watts - it would be called VA (volt amperes) anyway.

So, I don't think the AC power factor applies in this question.


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.

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

On 05/12/2015 03:20, Danny D. wrote:
nospam wrote, on Fri, 04 Dec 2015 21:56:21 -0500:

1 super charger port rated up to 2.4a, leaving 4.4a for the remaining
four ports (if you assume the 6.8a is correct), except those four ports
are rated up to 1a (not 1.1a), for a total of 6.4a (not 6.8a), or 32w.

32 Watts is even worse then, for the 40 watt claims.

The UL test report doesn't look right though.
http://umbraco-ljprodukter.utv2.toxi...20UL%2060W.pdf



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.

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

On 07/12/2015 00:20, Bruce Sinclair wrote:
In article , "Danny D." wrote:
tlvp wrote, on Wed, 02 Dec 2015 01:30:49 -0500:

Bought any resistors or capacitors lately? Resistors are commonly sold
with nominal values +/- 20%; capacitors, with +100/-50%. +/-15% may not
be high precision, but it's better than common precision .

And anyway, 35 isn't a whole 15% less than 40, it's only 12.5% less, if
we're going to try for highest arithmetic precision here . No big deal.

If I bought a precision resistor, and it was off by 15%, I'd be upset.

Precision is what you pay for in a resistor. A lot.


1% tolerance resistors are dirt cheap nowadays.

The last 0.1% ones didn't cost that much either.

--

Brian Gregory (in the UK).
To email me please remove all the letter vee from my email address.

On Fri, 5 Feb 2016 01:39:54 +0000, Brian Gregory
wrote:

On 30/11/2015 17:55, Danny D. wrote:
Scott Lurndal wrote, on Mon, 30 Nov 2015 17:38:04 +0000:

Q1: Since 6.8A times 5VDC is only 34Watts (not 40 Watts), how
can they very clearly label it as a 40Watt device?

http://www.powerstream.com/VA-Watts.htm

Here is a better (bigger) picture of the unit:
https://i.imgur.com/8bl7ypU.jpg
And a better (bigger) picture of the package:
https://i.imgur.com/30qxupn.jpg

I thank you for the reference, but, after reading it, I don't
see how that article helps explain the *output* wattage
descrepancy between 6.8A x 5VDC and the stated output spec
of 40Watts.

That article explains how to convert Volt-Amps to Watts.
"How to convert VA to Watts and KVA to Kilowatts"
http://www.powerstream.com/VA-Watts.htm

The input voltage is AC so roughly the input wattage is:
110VAC RMS times 800mA (max) which is roughly 88VA

But it's the OUTPUT wattage that is stated to be 40Watts.
6.8Amps x 5.0VDC is only 34 Watts

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.


Hence, a rather large 15% descrepancy (6 watts less than
40 watts).

I'm sure my math on the output wattage is wrong because
the package can't be wrong (that would be illegal), so,

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.


I don't see where my math went wrong yet though.

So, any advice is welcome and I will check it out.

It's what you call (in)efficiency.