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Weird power issue
05-11-2019, 11:51 AM (This post was last modified: 05-11-2019 11:52 AM by Tugdual.)
Post: #1
Weird power issue
I plugged the G2 to recharge its battery and all the sudden the screen started blinking frantically with a very bright white screen (I didn't think it could be so bright, almost like a phone flash led!). I unplugged it immediately and the charge was 100% which didn't make sense. Left it as is for the night and found it back to normal today, like half loaded as expected. Put it back on charge and everything seems fine.
I really thought it was toasted and now I'm scared it might have some defect. Anybody ever witnessed something similar?
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05-11-2019, 12:12 PM
Post: #2
RE: Weird power issue
Nope. New to me...

TW

Although I work for the HP calculator group, the views and opinions I post here are my own.
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05-11-2019, 12:50 PM (This post was last modified: 05-11-2019 12:54 PM by DrD.)
Post: #3
RE: Weird power issue
You might check for ac ripple current from the G2 power supply source. So called, "hum" which could cause this effect. (Any variation in the DC output from the power supply).

This might be a little tricky to detect, without measurement equipment. However, if you have an alternate power supply source, you could see if that one makes any difference in the blinking intensity, etc., between the two sources.

-Dale-
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05-11-2019, 09:32 PM
Post: #4
RE: Weird power issue
I must mention that when the issue happenned I was trying to reload with my phone fast Samsung charger. Back home I am using a less powerful Apple charger. Could this be the issue?
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05-11-2019, 10:04 PM
Post: #5
RE: Weird power issue
(05-11-2019 09:32 PM)Tugdual Wrote:  I must mention that when the issue happenned I was trying to reload with my phone fast Samsung charger. Back home I am using a less powerful Apple charger. Could this be the issue?

It could be. I would stick with the Power Adapter that came with your Prime. All power adapters with the same connector type are NOT created equal, and just because it fits, does not mean it's OK to use.

--Bob Prosperi
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05-11-2019, 10:50 PM
Post: #6
RE: Weird power issue
(05-11-2019 10:04 PM)rprosperi Wrote:  It could be. I would stick with the Power Adapter that came with your Prime. All power adapters with the same connector type are NOT created equal, and just because it fits, does not mean it's OK to use.
Well, this is wise but Hp doesn’t package any adapter with the G2, only a 1 USB cable.
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05-12-2019, 12:04 AM (This post was last modified: 05-12-2019 12:05 AM by rprosperi.)
Post: #7
RE: Weird power issue
(05-11-2019 10:50 PM)Tugdual Wrote:  
(05-11-2019 10:04 PM)rprosperi Wrote:  It could be. I would stick with the Power Adapter that came with your Prime. All power adapters with the same connector type are NOT created equal, and just because it fits, does not mean it's OK to use.
Well, this is wise but Hp doesn’t package any adapter with the G2, only a 1 USB cable.

What!?!? Off with their heads!!

Does the pkg. say what adapter power is recommended (i.e. Current range, something like 0.5-1.0A or similar)?

And I noticed the price was not reduced as a result of removing the adapter!

Jose is right, things are getting worse all over... Sad

Sorry for inappropriate advice.

--Bob Prosperi
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05-12-2019, 12:45 AM
Post: #8
RE: Weird power issue
(05-11-2019 09:32 PM)Tugdual Wrote:  I must mention that when the issue happenned I was trying to reload with my phone fast Samsung charger. Back home I am using a less powerful Apple charger. Could this be the issue?

My Samsung tablet charger says the output is 5.3V @ 2.0A so yeah, that might be it! Check your label...

Who decides?
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05-12-2019, 06:37 AM (This post was last modified: 05-12-2019 06:47 AM by jebem.)
Post: #9
RE: Weird power issue
(05-11-2019 10:50 PM)Tugdual Wrote:  
(05-11-2019 10:04 PM)rprosperi Wrote:  It could be. I would stick with the Power Adapter that came with your Prime. All power adapters with the same connector type are NOT created equal, and just because it fits, does not mean it's OK to use.
Well, this is wise but Hp doesn’t package any adapter with the G2, only a 1 USB cable.

There is a logical explanation for that Prime behavior.

Fast chargers are able to supply in excess of 5 amperes depending on the smartphone device being able to consume that current.
But that large current ability is not the primary reason for that Prime behavior.

What those fast chargers do is to supply up to 20 Volt in riple mode to force more current into the device being charged. This is well above the standard 5 Volt expected by the Prime, i would say.

We all know the Ohm's law, so roughly the current passing on the device depends on the source voltage divided by the device's impedance.
Therefore a chager able to supply in excess of 2 Ampere is not the issue because the device will only consume what it needs.
However if you feed well above the standard 5 Volt as used in regular chargers compatible with USB 1 or 2 or 3.0 protocol, then the device may be forced to pass higher current than needed.

Whether the Prime is able to cope with these modern USB 3.1 fast chargers is dependent on the incorporated hardware and firmware to handle that, and only the manufacturer is able to tell.

Jose Mesquita
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05-12-2019, 06:50 AM
Post: #10
RE: Weird power issue
(05-12-2019 12:45 AM)mfleming Wrote:  My Samsung tablet charger says the output is 5.3V @ 2.0A so yeah, that might be it! Check your label...

Just because a charger says "2.0A" on it doesn't mean that it will ram 2 amperes down the throat of anything you plug it into. It means that it will supply up to 2 amperes if demanded.

The 5.3V is higher than usual and just outside the 4.4V-5.25V tolerance of a USB 2.0 port. Let's also not forget that there is no doubt a tolerance for the 5.3V written on the charger, so you could potentially be pumping even more than that into the Prime. Bad idea!

No fast charger will go into fast charge mode unless there has been a successful negotiation between it and the device wanting the fast charge. Your Samsung tablet knows how to ask the charger for more juice, the HP Prime doesn't, or certainly shouldn't!
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05-13-2019, 10:42 AM
Post: #11
RE: Weird power issue
(05-12-2019 12:04 AM)rprosperi Wrote:  Does the pkg. say what adapter power is recommended (i.e. Current range, something like 0.5-1.0A or similar)?
I double checked the whole original packaging and doc it only says "rechargeable" and that is it. There is also a picture where you see that you're supposed to plug the cable in a USB plug. That was helpful. But no gripe, all is well, I don't mean to offend some personal sentitivity on the forum.
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05-13-2019, 11:02 AM (This post was last modified: 05-13-2019 11:08 AM by Zaphod.)
Post: #12
RE: Weird power issue
(05-12-2019 06:37 AM)jebem Wrote:  Fast chargers are able to supply in excess of 5 amperes depending on the smartphone device being able to consume that current.

True, but this has no bearing cos the device will draw as much current as it needs, up to the maximum deliverable by the power supply. AT that point the power supply will current limit or shut down (or even reduce) current output.

Quote:What those fast chargers do is to supply up to 20 Volt in riple mode to force more current into the device being charged. This is well above the standard 5 Volt expected by the Prime, i would say.

Begging your pardon, unless there's something being lost in translation?, but this is nonsense!. USB is USB, it follows standards.
USB3/USBC allows a different charging voltage which can be 20VDC, but that's USB3/C
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05-13-2019, 05:15 PM
Post: #13
RE: Weird power issue
(05-13-2019 11:02 AM)Zaphod Wrote:  
(05-12-2019 06:37 AM)jebem Wrote:  Fast chargers are able to supply in excess of 5 amperes depending on the smartphone device being able to consume that current.

True, but this has no bearing cos the device will draw as much current as it needs, up to the maximum deliverable by the power supply. AT that point the power supply will current limit or shut down (or even reduce) current output.

Quote:What those fast chargers do is to supply up to 20 Volt in riple mode to force more current into the device being charged. This is well above the standard 5 Volt expected by the Prime, i would say.

Begging your pardon, unless there's something being lost in translation?, but this is nonsense!. USB is USB, it follows standards.
USB3/USBC allows a different charging voltage which can be 20VDC, but that's USB3/C
Considering the very low impedance of batteries, 20V would be an absolute killer! I checked my La Crosse battery charger and found that the max 1A is delivered with 1.5V that is only 0.3V above nominal battery voltage.
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05-13-2019, 05:27 PM
Post: #14
RE: Weird power issue
(05-13-2019 11:02 AM)Zaphod Wrote:  
(05-12-2019 06:37 AM)jebem Wrote:  Fast chargers are able to supply in excess of 5 amperes depending on the smartphone device being able to consume that current.

True, but this has no bearing cos the device will draw as much current as it needs, up to the maximum deliverable by the power supply. AT that point the power supply will current limit or shut down (or even reduce) current output.

Quote:What those fast chargers do is to supply up to 20 Volt in riple mode to force more current into the device being charged. This is well above the standard 5 Volt expected by the Prime, i would say.

Begging your pardon, unless there's something being lost in translation?, but this is nonsense!. USB is USB, it follows standards.
USB3/USBC allows a different charging voltage which can be 20VDC, but that's USB3/C

This. I charge mine with several Apple/Samsung USB bricks. They all work fine, as USB is designed to.

If you are using something that uses USB3/C or whatever, taht could be the issue. I have a couple of USB C devices whose bricks cannot be used with other devices.
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05-14-2019, 04:38 PM
Post: #15
RE: Weird power issue
(05-13-2019 11:02 AM)Zaphod Wrote:  
(05-12-2019 06:37 AM)jebem Wrote:  Fast chargers are able to supply in excess of 5 amperes depending on the smartphone device being able to consume that current.

True, but this has no bearing cos the device will draw as much current as it needs, up to the maximum deliverable by the power supply. AT that point the power supply will current limit or shut down (or even reduce) current output.

Quote:What those fast chargers do is to supply up to 20 Volt in riple mode to force more current into the device being charged. This is well above the standard 5 Volt expected by the Prime, i would say.

Begging your pardon, unless there's something being lost in translation?, but this is nonsense!. USB is USB, it follows standards.
USB3/USBC allows a different charging voltage which can be 20VDC, but that's USB3/C

There's also the Qualcomm fast-charging "standards" as used by e.g. Samsung, who ship dual 5V/9V mains adaptors with their phones & tablets, over a USB connection.

Cambridge, UK
41CL 12/15C DM15/16 71B 17B/BII/bII+ 28S 42S/DM42 48GX 50g 35s 30b/WP34S Prime G2
& Casios, Rockwell 18R :)
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