Trying to understand the current draw of a Samsung Galaxy S3

[(PeteCresswell)]

Per Danny D.:

I realized the
constant "GPS signal lost" audible warnings
were actually due to the fact the battery was
at 17%.

Worse yet, apparently 17% is the critical point
in the curve where the phone can't keep up with
the GPS and the GPS keeps shutting off (rendering
it useless)....

I rooted my N7000 Note and removed everything that I could think of that
was not there for *me*.

I think it helped a little on battery consumption and I could usually
make it through a day without getting below 30%.

But every so often, this phone will draw an unexpected and unexplained
amount and the battery's charge will drop a *lot* in a few hours.

That being the case, I opted for a double-capacity battery from Mugen
and it seems to have reduced my chances of running dry during a day's
use to zero.

If ZeroLemon made one of their triple-capacity batteries for the N7000,
I would have bought one. They do make one for the S3:
http://www.youtube.com/watch?v=x7NTukwTDOM
--
Pete Cresswell

 

[Jon Elson]

Danny D. wrote:

Why would a 2.1 Amp charger not be enough to both charge
and run the phone, and why would it lose charge when the
battery is at 17% yet it maintains charge when the battery
is at 65%?

Most likely the electrical connection between the phone
and the car's noisy electrical system was trashing the
GPS receiver. If you know how TINY the GPS signal was at
the ground, you'd marvel that ANY GPS works at all. There is
a 50 W transmitter feeding an omni-directional antenna on
a satellite 400 miles up, that blankets a wide spot on
earth, several thousand miles wide with signal. That leaves
VERY little signal for the receiver to pick up. Any interference
will trash it and it can't get a valid fix.

Jon

 

[TJ]

On 01/31/2014 12:17 PM, Danny D. wrote:

On Fri, 31 Jan 2014 07:01:29 -0800, dave wrote:

Turn off GPS.
Turn off mobile data
Voice and Text are not on Mobile Data.

Luckily, I don't even have mobile data.
I do use GPS navigation all the time in the car though.
That's the whole point!

If the phone can't keep up with the GPS while
on the car charger, um, what good is GPS?

Note: I have gone on long trips (4 hours), and
if the battery is charged (say, >50%) it stays
at about that level; but if the battery is low
(say <20%), then the battery steadily depletes.

That's the enigma I'm trying to understand.

Perhaps your best solution would be to use the phone as a phone, and
purchase a separate GPS unit to use for navigation.

TJ

 

[Neil Gould]

Danny D. wrote:

On Fri, 31 Jan 2014 17:23:56 +0000, Danny D. wrote:

The enigma is that, if the charger is actually putting
out 2.1 Amps, then, why isn't 2.1 Amps enough to run the S3?

I should note that I *do* realize the charger doesn't
"put out" current (as it does voltage); what I meant,
clarified, is:

The enigma is that, if the charger is capable of
sourcing 2.1 Amps, then, why isn't that enough to
run the Samsung Galaxy S3 with operative GPS?

Have you verified that the charger is delivering even 1 Amp (that would be
more than adequate, since that is above what the phone requires)? Testing it
isn't all that difficult, but it does require some knowledge of electronics.

The charging circuit in the phone determines how much power is used to
operate the phone and other functions such as GPS vs. recharging the
battery. It is possible that the design of that circuit will not supply
adequate power to other functions when the battery is down to 17%.
--
best regards,

Neil

 

[Danny D'Amico]

On Fri, 31 Jan 2014 17:42:44 -0500, TJ wrote:

Perhaps your best solution would be to use the phone as a phone, and
purchase a separate GPS unit to use for navigation.

Yeah. Maybe. I get your point.
But, I think that there is something *wrong* that I can diagnose and fix.

1. It could be rogue apps sucking power.
2. The battery tests good - but it could be the battery.
3. The charger needs to be tested to see what current it supplies.
4. It could be a design flaw

I'm sure there are lots of potential reasons, but, what I'm going
to do is try to measure the actual current in the USB cable.

For that, I plan to sacrifice a cable and hook up some test leads.

 

[Danny D'Amico]

On Fri, 31 Jan 2014 18:25:42 -0500, Neil Gould wrote:

> Have you verified that the charger is delivering even 1 Amp

Nope. All I know is what is printed on the charger.
So, it *could* be simply that the charger isn't sourcing the
rated current.

I plan on sacrificing a USB cable to that I can hook an
ammeter in series to test the actual current flowing.

It is possible that the design of that circuit will not supply
adequate power to other functions when the battery is down to 17%.

I hope not, but I certainly understand what you're saying.
That's why I'm asking here - which is to see if others have similar
issues - or if it's just me.

 

[Chris Uppal]

Danny D'Amico wrote:

OPEN QUESTIONS:
- I still don't know how to tell how much current is actually drawn.

I've mentioned, in a recent thread, that you can buy in-line USB ammeters; the
one I use is from portapow.co.uk/ (who also sell power-only cables and other
goodies). Available on Amazon.

(BTW, there was some discussion in that thread of whether data could flow
through the meter -- it seems to be OK through the portapower gadget, though I
won't want to trust it for important data)

- None of the Android battery apps I tried gave current draw in amps.
- Instead, they listed charge in cryptic terms such as "12%/h".

"CurrentWidget" will display amps if the data is available, but the output
isn't consistant with (always much lower than) the portapower gadget's reports.
Presumably they are reporting different things.

And, reverting to your earlier puzzlement, maybe the reason why your phone
discharges faster when < ~17% full is that below that limit it is firing up
bluetooth to warn you that power is low. Above that limit it doesn't bother so
its overall power consumption is lower, thus allowing it to charge (or at
least, not discharge) on nett.

-- chris

 

[Capt Rick]

On Sat, 1 Feb 2014 07:08:11 +0000 (UTC), Danny D'Amico
<danny@is.invalid> wrote in part:

I plan on sacrificing a USB cable to that I can hook an
ammeter in series to test the actual current flowing.

No need to sacrifice a USB cable. Measure the current going into the
cigarette lighter adapter. Measure without the Galaxy plugged in for
any idle current. Plug in the Galaxy. Subtract idle current then
multiply by 2.52 for a rough figure - 12.6V / 5V = 2.52. For more
accuracy measure the actual 12V Voltage and the actual 5V Voltage of
the USB output.

The current will be less on the 12V end because it is a step down
circuit. Just for example, if 1A on the 12V side, 12.6V X 1A = 12.6
Watts / 5V X 2.52A = 12.6 Watts.

Rick

 

[Gordon Levi]

Danny D'Amico <danny@is.invalid> wrote:

On Fri, 31 Jan 2014 17:42:44 -0500, TJ wrote:

Perhaps your best solution would be to use the phone as a phone, and
purchase a separate GPS unit to use for navigation.

Yeah. Maybe. I get your point.
But, I think that there is something *wrong* that I can diagnose and fix.

1. It could be rogue apps sucking power.
2. The battery tests good - but it could be the battery.
3. The charger needs to be tested to see what current it supplies.
4. It could be a design flaw

I'm sure there are lots of potential reasons, but, what I'm going
to do is try to measure the actual current in the USB cable.

For that, I plan to sacrifice a cable and hook up some test leads.

For five dollars with free shipping you may prefer this
<http://tinyurl.com/maqfv9r>. I don't own anything similar so I can't
provide a recommendation. As I understand it, the cheap ones like this
can't pass through the data.

 

[TJ]

On 02/01/2014 02:05 AM, Danny D'Amico wrote:

On Fri, 31 Jan 2014 17:42:44 -0500, TJ wrote:

Perhaps your best solution would be to use the phone as a phone, and
purchase a separate GPS unit to use for navigation.

Yeah. Maybe. I get your point.
But, I think that there is something *wrong* that I can diagnose and fix.

1. It could be rogue apps sucking power.
2. The battery tests good - but it could be the battery.
3. The charger needs to be tested to see what current it supplies.
4. It could be a design flaw

I'm sure there are lots of potential reasons, but, what I'm going
to do is try to measure the actual current in the USB cable.

For that, I plan to sacrifice a cable and hook up some test leads.

I'd discount 4. Too many of those units around. A design flaw would have
surfaced by now. That's not to say your particular phone isn't
malfunctioning, though. A couple of years ago I purchased a
factory-authorized reconditioned Samsung 23" LCD monitor. It worked
great - for a year - before it succumbed to the infamous
bad-capacitor-in-the-power-supply syndrome. But things worked out,
because I replaced it with a new AOC LED-backlit monitor which draws
less power, has an easily-replaceable external power supply, and works
even better than the Samsung. Even so, it taught me that buying Samsung
is not necessarily a guarantee of long service.

It sounds like you've run down your battery several times. That's not
good for them. From what I read, it shortens the life expectancy. If
it's been in service for a year or more, and you've run it in a
low-charge condition repeatedly, it would be my prime suspect.

The Chinese-made charger would be my second. My third would be that
you're trying to make the phone do more heavy-duty multitasking than
it's designed to handle.

TJ

 

[TJ]

On 02/01/2014 06:17 AM, Capt Rick wrote:

On Sat, 1 Feb 2014 07:08:11 +0000 (UTC), Danny D'Amico
danny@is.invalid> wrote in part:


I plan on sacrificing a USB cable to that I can hook an
ammeter in series to test the actual current flowing.

No need to sacrifice a USB cable. Measure the current going into the
cigarette lighter adapter. Measure without the Galaxy plugged in for
any idle current. Plug in the Galaxy. Subtract idle current then
multiply by 2.52 for a rough figure - 12.6V / 5V = 2.52. For more
accuracy measure the actual 12V Voltage and the actual 5V Voltage of
the USB output.

The current will be less on the 12V end because it is a step down
circuit. Just for example, if 1A on the 12V side, 12.6V X 1A = 12.6
Watts / 5V X 2.52A = 12.6 Watts.

Rick

Don't know about modern vehicles, but I believe that with older ones if
the vehicle is running, the alternator puts the voltage at more like
13.6V, especially if it's still charging the battery after starting the
engine. Could be higher with a high-output alternator. They cut back
once the battery is charged, but there is that period of time where it's
higher.

TJ

 

[(PeteCresswell)]

Per dave:
>Turn off GPS. It will drain your battery fast.

That's what I keep reading, but it does not match my experience with a
Samsung 10" Note.

I rooted the thing and cleaned out everything I could think of and it
holds a charge so well that I hardly ever turn it off.

With GPS on I can leave it with screen black for a day and it will lose
less than 5% of it's charge. OTOH, maybe GPS is not working when the
screen is black..... ??
--
Pete Cresswell

 

[(PeteCresswell)]

Per TJ:

Perhaps your best solution would be to use the phone as a phone, and
purchase a separate GPS unit to use for navigation.

I think he would be on the wrong side of history if he did that.

I gave my Garmin Nuvi away last year and have been using Sygic on my 5"
and 10" Notes ever since.

I'm not a heavy driver, but so far I would have to say that Sygic is
plenty good enough for me - in fact, it's turn advisories are somewhat
better than the Garmin.

Only place I'd fault it is announcements of route recomputation. Garmin
would right away say "Recomputing Route" as soon as I departed from it's
route. Sygic issues a couple of "Make A U-Turn" directives and then
just silently recomputes the route. I found that disconcerting and a
little confusing at first but now that I know what's coming I'm used to
it.
--
Pete Cresswell

 

[Danny D'Amico]

On Sat, 01 Feb 2014 11:16:06 +0000, Chris Uppal wrote:

maybe the reason why your phone discharges faster when < ~17%
full is that below that limit it is firing
up bluetooth to warn you that power is low.

I guess if I had a better understanding of how the GPS and
bluetooth consumed power, I'd be better off.

One thing about the bluetooth, since I have a bluetooth speaker
in the vehicle, it's always "talking" to the bluetooth for
phone calls and for GPS - although I don't know how much the
bluetooth needs to 'fire up' to say "GPS signal lost" and
"GPS signal reacquired'.

One thing that 'seems' to have made a difference in the
ensuing days is that I've installed a plethora of battery
monitor freeware on the S3.

A bunch of them were garbage, so I deleted them soon after
first using them, but, the ones still on my phone are:

a. Battery Doctor
b. Battery Monitor Widget
c. Elixr & Elixr2

And, in a different category:
a. Wakelock Detector (uZumm Apps)

I'm not sure what combination of things made the problem less
severe, but, using these programs, I was able to find the high
draining ones, and I uninstalled most of the culprits, I think.

I do like how, for example, Battery Doctor, kills twenty running
apps at a time, all of which I hadn't even realized were running.

For example, unbeknownst to me, the Chinese mapping program,
ZNavi, was apparently using the GPS all the time, even when GPS
was turned off on the phone. So I uninstalled it, and a few
other programs that kept waking up the phone, or running in
the background.

So, now I have the operating system being the main consumer
of power at 75% with all other programs only consuming in the
single digits of battery percentage.

I need to test on the road, but, I am hopeful that this
"optimization" (which had yielded surprising results)
will help somewhat.

 

[Danny D'Amico]

On Sat, 01 Feb 2014 11:16:06 +0000, Chris Uppal wrote:

> I've mentioned, in a recent thread, that you can buy in-line USB ammeters;

I'm going to consider that, although my "plan" was simply to cut
an existing usb cable in half, and wrapping the wires around a
bunch of brass screws sticking out of a piece of wood.

However, for convenience, and longer-term data, the inline
ammeters do seem to be useful, and not a lot of money.

 

[Danny D.]

On Sat, 01 Feb 2014 09:21:44 -0500, (PeteCresswell) wrote:

Only place I'd fault it is announcements of route recomputation. Garmin
would right away say "Recomputing Route" as soon as I departed from it's
route. Sygic issues a couple of "Make A U-Turn" directives and then
just silently recomputes the route. I found that disconcerting and a
little confusing at first but now that I know what's coming I'm used to
it.

I had the same experience with Sygic, only much worse.
I was on a well-known shortcut (highway 84 in Livermore)
between i680 and i580 and Sygic, for fifteen miles, kept
telling me to make a u-turn.

It wasn't until I was almost at i580 that Sygic finally
decided to recalculate.

In contrast, Navigator freeware recomputes within 100 or 200
feet of missing an intersection.

On the other hand, the Sygic 3D display is absolutely gorgeous,
and, even better than that of the Garmin nĂźvi!

 

[Danny D.]

On Sat, 01 Feb 2014 05:17:38 -0600, Capt Rick wrote:

No need to sacrifice a USB cable.
Measure the current going into the
cigarette lighter adapter.

Now why hadn't I thought of that!

I can just hook an ammeter across the fuse
for the cigarette lighter socket, which
will give me the current being consumed
with, and without the phone being charged!

 

[Danny D.]

On Sat, 01 Feb 2014 09:17:30 -0500, (PeteCresswell) wrote:

With GPS on I can leave it with screen black for a day and it will lose
less than 5% of it's charge. OTOH, maybe GPS is not working when the
screen is black..... ??

Wow. Today I removed the S3 from the wall charger,
and, within 5 hours, the battery was nearly dead.

When I looked to see what was consuming the power,
I found, much to my surprise, that "Google Play Services"
consumed more power than the Android operating system!

http://farm8.staticflickr.com/7412/12261909853_b6c685ceab_o.gif

 

[Danny D.]

On Fri, 31 Jan 2014 06:59:53 +0000, Andy Burns wrote:

Does the phone detect the charger as capable of
delivering high current? If so, it should display
"Charging A/C" instead of "Charging USB"

Testing for this, I found 4 different possible reports:
http://farm8.staticflickr.com/7369/12262187304_780eeb227a_o.gif

1. Charging (AC)

2. Charging (USB)

3. Charging

4. Full

 

In sci.electronics.repair Danny D. <dannyd@nowhere.invalid> wrote:

On Sat, 01 Feb 2014 05:17:38 -0600, Capt Rick wrote:

No need to sacrifice a USB cable. Measure the current going into the
cigarette lighter adapter.

I can just hook an ammeter across the fuse for the cigarette lighter
socket, which will give me the current being consumed with, and
without the phone being charged!

Check the current across the lighter fuse in three conditions:

1. Nothing plugged in to the lighter socket.

2. Charger plugged in to the lighter socket, but phone not plugged in
to the charger.

3. Charger plugged in to the lighter socket and phone plugged in to
the charger.

1 is because, on some cars, the "lighter" fuse also supplies a small
amount of current for other things, like keeping time in a clock, or
keeping the station memory in the radio - stuff like that. It might not
be weird to measure a few mA on that circuit even with nothing plugged
in to the cigarette lighter.

In newer cars, the trend is to have more fuses for individual circuits,
so this may not happen in your car. If your cigarette lighter switches
on and off with the ignition (a lot of Japanese cars do this), then this
may not happen in your car either.

Matt Roberds