Trying to understand the current draw of a Samsung Galaxy S3 under GPS & low battery
 

In sci.electronics.repair Danny D. 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

Trying to understand the current draw of a Samsung Galaxy S3 under GPS & low battery
 

Per Danny D.:
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/7412/1...c685ceab_o.gif

The app that I use to remove unwanted system apps is called App Master.

It allows apps to be put in it's "Recycle Bin" from which they can be
restored.

So I'm not all that hesitant about uninstalling something. If the
device starts getting weird, I just restore it. The trick being, of
course, not to uninstall anything that would prevent App Master from
doing it's Restore thing...
--
Pete Cresswell

Trying to understand the current draw of a Samsung Galaxy S3under GPS & low battery
 

(PeteCresswell) wrote:
Per Danny D.:
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/7412/1...c685ceab_o.gif

The app that I use to remove unwanted system apps is called App Master.

It allows apps to be put in it's "Recycle Bin" from which they can be
restored.

So I'm not all that hesitant about uninstalling something. If the
device starts getting weird, I just restore it. The trick being, of
course, not to uninstall anything that would prevent App Master from
doing it's Restore thing...

Combining both of your posts, is it possible that since Google knows about
all of the apps you bought from them and tracks them, will it attempt to
restore them if you delete them?

I don't know for sure but I have seen automatic updating of apps on my
android devices, and if I bought them (even for free), they try to
reinstall.

Geoff.

--
Geoffrey S. Mendelson, N3OWJ/4X1GM/KBUH7245/KBUW5379

Trying to understand the current draw of a Samsung Galaxy S3 under GPS & low battery
 

Per Geoffrey S. Mendelson:
Combining both of your posts, is it possible that since Google knows about all of the apps you bought from them and tracks them, will it attempt restore them if you delete them?

Good catch. I never considered that.

I'll start checking. Push comes to shove, I suspect I can uninstall
whatever does those automatic updates.
--
Pete Cresswell

Trying to understand the current draw of a Samsung Galaxy S3 under GPS & low battery
 

On Sun, 2 Feb 2014 05:48:18 +0000 (UTC), wrote:

... hook an ammeter across the fuse ...

You want the fuse and the ammeter to *share* the current being drawn?
Or you want to measure the current being drawn *through* the fuse?
If the latter, put the ammeter *in series* with the fuse (not across it).

HTH. Cheers, -- tlvp
--
Avant de repondre, jeter la poubelle, SVP.

Trying to understand the current draw of a Samsung Galaxy S3 under GPS & low battery
 

On 2/02/2014, (PeteCresswell) posted:
Per Geoffrey S. Mendelson:
Combining both of your posts, is it possible that since Google knows
about all of the apps you bought from them and tracks them, will it
attempt restore them if you delete them?

Good catch. I never considered that.

I'll start checking. Push comes to shove, I suspect I can uninstall
whatever does those automatic updates.

Google has never tried to restore any app that I have deleted.

Of course, some Google or phone makers' apps can't be deleted. OTOH,
some of those can be disabled; I've never had a disabled app reenabled.

--
Gene E. Bloch (Stumbling Bloch)

Trying to understand the current draw of a Samsung Galaxy S3 under GPS & low battery
 

On 2/02/2014, tlvp posted:
On Sun, 2 Feb 2014 05:48:18 +0000 (UTC), wrote:

... hook an ammeter across the fuse ...

You want the fuse and the ammeter to *share* the current being drawn?
Or you want to measure the current being drawn *through* the fuse?
If the latter, put the ammeter *in series* with the fuse (not across
it).

HTH. Cheers, -- tlvp

No: *replace* the fuse with the ammeter. Pull the fuse & plug the
ammeter's leads where the fuse's leads went (it's not easy!). Try
soldering wires to the leads of a blown fuse (that's not so easy
either).

Of course, if you knew the exact resistance of the fuse and had a
sufficiently sensitive voltmeter you could measure the drop across the
fuse. Good luck with that!

--
Gene E. Bloch (Stumbling Bloch)

Trying to understand the current draw of a Samsung Galaxy S3under GPS & low battery
 

This article was pointed out to me by Jeff L. and it is interesting in that it
explained the Chinese standard, the EU standard, and the Apple standard of USB
charging circuits:
http://blog.curioussystem.com/2010/0...vice-charging/

Apple, being different, used voltages for their charging circuitry:
- low current: 2.8 volts across Data(+)
- high current: 2.0 volts across Data(-)

The EU used a 1/8W 200 ohm resistor, & the Chinese simply short the data pins.

The five 1/8 watt resistor "hybrid" circuit in that article nicely explains how
a USB charger can work *either* for Apple (voltage) or EU (resistance) or
Chinese (short) charge circuits; but not all three at the same time!

Trying to understand the current draw of a Samsung Galaxy S3under GPS & low battery
 

Another related article that Jeff L. pointed out today was this:
http://instructables.com/id/Modify-a...an-iPod-iPhone

That article nicely further explains the Apple charging standard:
a) 2.0 V on D+ & 2.0 V on D- tells the Apple device it's a 500 mA port
b) 2.0 V on D+ & 2.8 V on D- tells the Apple device it's a 1 A port

Trying to understand the current draw of a Samsung Galaxy S3 under GPS & low battery
 

Going back to original query.
Ignoring all of the technical jargon, it could be that the GPS is
using power faster than it can be replaced.
According to the battery utility app on my Samsung Note 10.1 it takes
a very low battery in excess of 2.5hrs to charge on a mains charger,
but with a full battery the GPS will only function for 1hr and
39minutes. So the GPS is using power faster than even a mains
connection can replace it, it would be even faster with a USB
connection.

Trying to understand the current draw of a Samsung Galaxy S3under GPS & low battery
 

Danny D. has written on 2/1/2014 10:45 PM:
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!

(If you hook it across the fuse, you won't get the current you want.
Remove the fuse and connect the ammeter to the fuse terminals.)

Trying to understand the current draw of a Samsung Galaxy S3 under GPS & low battery
 

"TJ" wrote in message
...
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.

I actually find that the iphone 5 does a much better job
as a GPS receiver than the TomTom 710 it replaces and
gets a lot more time on the internal battery with the
GPS turned on too, and is a lot more convenient to use
because it does everything and the TomTom doesnt.