Can I charge my K3 using iPad's AC/USB adapter?

Over · 03-18-2011, 03:08 PM

My iPad, besides the usb/ipad cable, came with an AC/USB adapter, so I plug the USB cable there and it will charge faster than if I plug it to my PC.

I'm wondering if I could do the same with the Kindle 3 without damaging the batteries. Anyone knows?

Sylver · 03-18-2011, 03:26 PM

not a good idea. A normal USB wall charger does not work well with iPad, so you would think the iPad specific usb charger is much more powerful than standard usb charger, hence be harmful to your k3.

HarryT · 03-18-2011, 03:39 PM

Quote:

Originally Posted by Sylver

not a good idea. A normal USB wall charger does not work well with iPad, so you would think the iPad specific usb charger is much more powerful than standard usb charger, hence be harmful to your k3.

It will work just fine. The iPad charger is capable of supplying more current than a standard USB charger, yes, but it's the device being charged that determines how much current it wishes to draw. Charging something with a lower current draw on a charger that's capable of supplying more current is absolutely fine.

Over · 03-18-2011, 03:56 PM

Harry, I can see that you have both the K3 and iPad/iPhone. Have you ever tried that?

Dava · 03-18-2011, 04:07 PM

I tried to charge my K3 with the charger from my Samsung Galaxy. Despite charging all night the K3 only had about 90% charge after 8 hours... Is that normal?

The galaxy and the K3 has the same size of battery..

JMikeD · 03-18-2011, 04:16 PM

I routinely charge just about everything with an iPad charger. No problems. As HarryT said, the devices will only draw the power they need, they aren’t being "force-fed" a charge.

oggelbe2007 · 03-18-2011, 04:37 PM

USB is a well established standard serial interface with only 4 pins. Pin 1 is +5VDC and pin 4 is ground. Anything with a 'Standard' USB port will be able to charge from a USB cable connection.

HarryT · 03-18-2011, 06:15 PM

Quote:

Originally Posted by Over

Harry, I can see that you have both the K3 and iPad/iPhone. Have you ever tried that?

Yes. It works fine.

desertblues · 03-18-2011, 06:26 PM

Quote:

Originally Posted by HarryT

Yes. It works fine.

Ditto; do it all the time.

Over · 03-19-2011, 06:45 AM

Thanks guys. Very useful to know for sure.

dwig · 03-19-2011, 09:20 AM

Quote:

Originally Posted by JMikeD

I routinely charge just about everything with an iPad charger. No problems. As HarryT said, the devices will only draw the power they need, they aren’t being "force-fed" a charge.

The current (amps or milliamps) is something the load (read: device being charged) draws or pulls from the power source (charger). So in terms of the current, its true that the device is not being "force-fed". It draws only what it needs. If the charger can't supply the current that the device demands one of two things will happen; either the charger will be damaged by the excessive demand (not likely with modern current limiting circuits in chargers) or the device will have to live with the lower current (result: slower charging).

Voltage is different. It is the electrical analog of water pressure. In terms of voltage, the device is being "force-fed". Most modern electronic devices use circuits to regulate their input voltage. If the input voltage exceeds the maximum these circuits can handle, though, the device will be damaged.

jocampo · 03-19-2011, 09:36 AM

I think I asked a similar question months ago.

https://www.mobileread.com/forums/sho...d.php?t=115739

As long as Voltage is the same and current same or a bit higher, it should be fine, assuming the battery is not defective or gets too hot

speedlever · 04-11-2011, 10:01 AM

I've always found this confusing.

Just to summarize, it doesn't matter what the power source is, the device will take the charge at its own rate, up to the limit the power source can supply.

So I can charge my K3 from my computer USB ports, the Kindle charger, or my iPad charger... just using the USB charging cable that came with the Kindle charger.

And I can charge my iPad from the computer USB ports, the Kindle charger, or the iPad charger... just using the USB charging cable that came with the iPad charger.

I'll get about the same Kindle charging time and rate from the Kindle charger (0.85A) or the iPad charger (2.1A), and a slower charge from the computer USB ports (0.1A) since the K3 charger only shows 5v/0.85A which is equal to or less than the output of the K3 charger and the iPad charger but more than the output of the computer USB port.

I'll get the fastest iPad charge time and rate from the iPad charger, the next fastest from the K3 charger, and the slowest from the computer USB port.

And all this can be accomplished safely because the device draws the power it needs to recharge, it is not force fed from the power supply. Basically, anything with a USB connection can be safely charged from any USB power source, but the charge time will vary considerably.

Do I have this right?

Edit: source: http://en.wikipedia.org/wiki/Usb#Power
A unit load is defined as 100 mA in USB 2.0
A maximum of 5 unit loads (500 mA) can be drawn from a port in USB 2.0

FF2 · 04-11-2011, 10:52 AM

I just purchased one of those thingies that increase the number of sockets in a standard wall socket from two to three and it included two usb sockets so I thought it might be a nice addition to my collection (Meridian item #21602).

According to its packaging the usb is dc5v 350mA.

My Blackberry does not even notice it - no charging icon on the BB. I tried it on my k3. The yellow/orange light did come on but hours later the battery icon showed no change in power.

It does have an applied added label "Not compatible with all apple products."

ywen · 04-11-2011, 11:03 AM

the supplied AC -> USB adapter is 0.85A.. Does the K3 charge faster with an adapter that supplies more amps?

03-18-2011, 03:08 PM	#1
Over Wizard Posts: 1,462 Karma: 6061516 Join Date: May 2008 Location: Cascais, Portugal Device: Kindle PW, Samsung Galaxy Note Pro 12.2", OnePlus 6	Can I charge my K3 using iPad's AC/USB adapter? My iPad, besides the usb/ipad cable, came with an AC/USB adapter, so I plug the USB cable there and it will charge faster than if I plug it to my PC. I'm wondering if I could do the same with the Kindle 3 without damaging the batteries. Anyone knows?

03-18-2011, 04:37 PM	#7
oggelbe2007 Limited Warranty Posts: 89 Karma: 576 Join Date: Jul 2007 Location: North Georgia, USA Device: A sweet PRS-500, DXG	USB is a well established standard serial interface with only 4 pins. Pin 1 is +5VDC and pin 4 is ground. Anything with a 'Standard' USB port will be able to charge from a USB cable connection. Last edited by oggelbe2007; 03-18-2011 at 04:40 PM.

03-19-2011, 09:36 AM	#12
jocampo Layback feline Posts: 3,034 Karma: 6980745 Join Date: Nov 2010 Location: USA Device: Oasis 2nd gen, Sony DPTS1, iPad Pro 10.5"	I think I asked a similar question months ago. https://www.mobileread.com/forums/sho...d.php?t=115739 As long as Voltage is the same and current same or a bit higher, it should be fine, assuming the battery is not defective or gets too hot Last edited by jocampo; 03-19-2011 at 09:41 AM. Reason: Providing link to similar thread

04-11-2011, 10:01 AM	#13
speedlever Fanatic Posts: 592 Karma: 138200 Join Date: Nov 2010 Location: NC, USA Device: PW2014, PW2012, iPad Pro	I've always found this confusing. Just to summarize, it doesn't matter what the power source is, the device will take the charge at its own rate, up to the limit the power source can supply. So I can charge my K3 from my computer USB ports, the Kindle charger, or my iPad charger... just using the USB charging cable that came with the Kindle charger. And I can charge my iPad from the computer USB ports, the Kindle charger, or the iPad charger... just using the USB charging cable that came with the iPad charger. I'll get about the same Kindle charging time and rate from the Kindle charger (0.85A) or the iPad charger (2.1A), and a slower charge from the computer USB ports (0.1A) since the K3 charger only shows 5v/0.85A which is equal to or less than the output of the K3 charger and the iPad charger but more than the output of the computer USB port. I'll get the fastest iPad charge time and rate from the iPad charger, the next fastest from the K3 charger, and the slowest from the computer USB port. And all this can be accomplished safely because the device draws the power it needs to recharge, it is not force fed from the power supply. Basically, anything with a USB connection can be safely charged from any USB power source, but the charge time will vary considerably. Do I have this right? Edit: source: http://en.wikipedia.org/wiki/Usb#Power A unit load is defined as 100 mA in USB 2.0 A maximum of 5 unit loads (500 mA) can be drawn from a port in USB 2.0 Last edited by speedlever; 04-11-2011 at 10:04 AM.

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03-18-2011, 03:26 PM	#2
Sylver Addict Posts: 234 Karma: 40 Join Date: Apr 2010 Device: The Nook, iPad	not a good idea. A normal USB wall charger does not work well with iPad, so you would think the iPad specific usb charger is much more powerful than standard usb charger, hence be harmful to your k3.

03-18-2011, 03:56 PM	#4
Over Wizard Posts: 1,462 Karma: 6061516 Join Date: May 2008 Location: Cascais, Portugal Device: Kindle PW, Samsung Galaxy Note Pro 12.2", OnePlus 6	Harry, I can see that you have both the K3 and iPad/iPhone. Have you ever tried that?

03-18-2011, 04:07 PM	#5
Dava Enthusiast Posts: 25 Karma: 10 Join Date: Feb 2011 Location: Sweden Device: Samsung Galaxy I5700 Spica, Kindle 3	I tried to charge my K3 with the charger from my Samsung Galaxy. Despite charging all night the K3 only had about 90% charge after 8 hours... Is that normal? The galaxy and the K3 has the same size of battery..

03-18-2011, 04:16 PM	#6
JMikeD Evangelist Posts: 475 Karma: 15000 Join Date: Jul 2008 Device: Various and sundry	I routinely charge just about everything with an iPad charger. No problems. As HarryT said, the devices will only draw the power they need, they aren’t being "force-fed" a charge.

03-19-2011, 06:45 AM	#10
Over Wizard Posts: 1,462 Karma: 6061516 Join Date: May 2008 Location: Cascais, Portugal Device: Kindle PW, Samsung Galaxy Note Pro 12.2", OnePlus 6	Thanks guys. Very useful to know for sure.

04-11-2011, 10:52 AM	#14
FF2 Wizard Posts: 1,105 Karma: 1025784 Join Date: Oct 2010 Device: WiFi Kindle3	I just purchased one of those thingies that increase the number of sockets in a standard wall socket from two to three and it included two usb sockets so I thought it might be a nice addition to my collection (Meridian item #21602). According to its packaging the usb is dc5v 350mA. My Blackberry does not even notice it - no charging icon on the BB. I tried it on my k3. The yellow/orange light did come on but hours later the battery icon showed no change in power. It does have an applied added label "Not compatible with all apple products."

04-11-2011, 11:03 AM	#15
ywen Member Posts: 14 Karma: 126 Join Date: Apr 2011 Device: kindle 3 3g	the supplied AC -> USB adapter is 0.85A.. Does the K3 charge faster with an adapter that supplies more amps?

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