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I bought a couple car chargers, one is 5.25 volts (labeled) (and 1amp), and the other I tested with a DMM and it is 5.38v output and 2amps max.
I have not been able to test the charger that came with the unit because it wont plug into an American electric outlet.
when you test with a multimeter you get too high results, as there is no load on the dc-dc regulator. anyway all usb devices have voltage regulators inside, so should all be safe.
im not a pro at electronics but isnt it possible to solder a charging plug to a usb cable?
to achieve usb charging?
did it for a homemade IR headtracking unit
SmokeMasta said:
im not a pro at electronics but isnt it possible to solder a charging plug to a usb cable?
to achieve usb charging?
did it for a IR headtracking unit
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I still don't think people understand. This devices needs more output then a usb plug can produce. Think about it this way, would you charge your laptop computer off your desktop usb port? The XOOM requires a 12v charge, just like your laptop.
bwcorvus said:
I still don't think people understand. This devices needs more output then a usb plug can produce. Think about it this way, would you charge your laptop computer off your desktop usb port? The XOOM requires a 12v charge, just like your laptop.
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wont it be able to trickle charge... when in a pinch some charge is better then none at all
What don't people understand about this. A USB plug in a computer might only be able to produce 500ma, but you can plug that SAME USB cable into a wall charger that uses USB and it will charge fast as hell. The iPad does this. All Android phones do this. It makes it so you only have to carry one cable and maybe a small wall plug.
deleted this
bwcorvus said:
The usb port is not connected to the battery for charging anyway.
https://motorola-global-portal.cust...sion/L3RpbWUvMTI5ODgyOTM5NS9zaWQvdnpSbGhIbms=
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guess you missed prev poster point ... if you solder on a charging plug it doesnt mean you need to remove the other plug have 2 plugs on one side
SmokeMasta said:
guess you missed prev poster point ... if you solder on a charging plug it doesnt mean you need to remove the other plug have 2 plugs on one side
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You are right i miss read it
after some reading usb 3.0 delivers 900ma
and it looks those usb charger blocks deliver upto 9w at 1.8a
It is hard to say if it will work. Since I don't have my Xoom yet, I can looking at the output rating of the wall charger. Maybe someone can look at their wall charger and see how much output voltage and current it produces. If it's higher than 5V, the USB might not be able to charge it. If it could charge it, it would be better to have a USB cable that has one end split into two connectors, one with the circular connector, and one with the micro USB end.
ggoldfingerd said:
It is hard to say if it will work. Since I don't have my Xoom yet, I can looking at the output rating of the wall charger. Maybe someone can look at their wall charger and see how much output voltage and current it produces. If it's higher than 5V, the USB might not be able to charge it. If it could charge it, it would be better to have a USB cable that has one end split into two connectors, one with the circular connector, and one with the micro USB end.
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Here you go.
looks like my usb 1.0 charger (from htc (ancient thing)) delivers 5v at 1amp
wondering if newer chargers deliver more. spec sheet of USB 3.0 says it can deliver 9 volt at 1.8 amp
hopefully the EU classifies the moto tablet as a telephone then its obligated by law to have usb charging ability
The iPad charger delivers 5v at 2 amps over a USB to 30pin cable.
bwcorvus said:
Here you go.
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Thanks. I just decided to glance at the Xoom teardown. From what I saw with the hardware, I don't think it will be possible to use USB to charge it. The battery alone is 7.4V, so there is no way to charge it with 5V unless the Xoom had a DC step-up convert. The teardown only lists a step-down converter which probably steps the battery voltage down for all of the components in the Xoom and has nothing to do with battery charging.
ggoldfingerd said:
Thanks. I just decided to glance at the Xoom teardown. From what I saw with the hardware, I don't think it will be possible to use USB to charge it. The battery alone is 7.4V, so there is no way to charge it with 5V unless the Xoom had a DC step-up convert. The teardown only lists a step-down converter which probably steps the battery voltage down for all of the components in the Xoom and has nothing to do with battery charging.
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Does it require the same voltage to do a trickle charge? From the research XDA members have done so far, the Xoom charger requires 1.5A, USB puts out .5A, that's not too far off if we just want trickle charging.
The battery is 7.4V but 5V isn't too far off either.
Does the market app SPARE PARTS work on the Xoom, or some other charging monitor app?
Maybe someone who already has the Xoom and knows how to solder can frankenstein a USB charging adapter? Make one end fit into the charging port of the Xoom and the other end fit into a standard micro USB plug.
This way, you carry your normal USB cable for data transfer but if you need to charge, then you plug the USB plug into the adapter which plugs into the charging port.
BTW, can someone please clarify that the charging port IS THE ONLY WAY to charge the Xoom? Someone said on here that the docking device has a USB plug that will charge the Xoom thru the USB?
Neo3D said:
Does it require the same voltage to do a trickle charge? From the research XDA members have done so far, the Xoom charger requires 1.5A, USB puts out .5A, that's not too far off if we just want trickle charging.
The battery is 7.4V but 5V isn't too far off either.
Does the market app SPARE PARTS work on the Xoom, or some other charging monitor app?
Maybe someone who already has the Xoom and knows how to solder can frankenstein a USB charging adapter? Make one end fit into the charging port of the Xoom and the other end fit into a standard micro USB plug.
This way, you carry your normal USB cable for data transfer but if you need to charge, then you plug the USB plug into the adapter which plugs into the charging port.
BTW, can someone please clarify that the charging port IS THE ONLY WAY to charge the Xoom? Someone said on here that the docking device has a USB plug that will charge the Xoom thru the USB?
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Spare parts works fine, so does battery monitor widget. The dock uses the 2 metal pins between the hdmi and charging hole.
My HTC charger outputs from the AC adapter to microusb at 5V and 1.0A, which is as high as I've seen with other phones and chargers.
The Xoom charger appears to output 12V at 1.5A.
I'm no electrician but that does seem like a pretty big difference. 140% greater in and 50% greater respectively.
A lot of armchair electrical engineers in here. Tell me, what would you gain from creating your own proprietary usb charger? You'd still have only one of them and you couldn't use it on anything else.
Has anyone stopped to think that it's very highly likely that the usb charging pins aren't hooked up at all inside the xoom?
This forum is the biggest group of whiny people I've ever encountered, and I once accidentally walked into a GoP fundraiser.
Neo3D said:
Does it require the same voltage to do a trickle charge? From the research XDA members have done so far, the Xoom charger requires 1.5A, USB puts out .5A, that's not too far off if we just want trickle charging.
The battery is 7.4V but 5V isn't too far off either.
Does the market app SPARE PARTS work on the Xoom, or some other charging monitor app?
Maybe someone who already has the Xoom and knows how to solder can frankenstein a USB charging adapter? Make one end fit into the charging port of the Xoom and the other end fit into a standard micro USB plug.
This way, you carry your normal USB cable for data transfer but if you need to charge, then you plug the USB plug into the adapter which plugs into the charging port.
BTW, can someone please clarify that the charging port IS THE ONLY WAY to charge the Xoom? Someone said on here that the docking device has a USB plug that will charge the Xoom thru the USB?
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Well the current rating is only part of the equation. Think of the voltage as the pushing force for the current. The Xoom has two Li-Po packs (two batteries) with a nominal voltage of 7.4V. It really depends on the battery, but in general for Li-Po's, the minimum voltage for this battery will be something close to 6V. Li-Po's require specific ways of charge with min/max voltages and certain currents. The minimum battery voltage cannot be overcome by the 5V from USB, thus it will not charge the battery.
If anything, the 5V could power the device, but it wouldn't charge the battery. I would bet that this doesn't work. The power jack on the Xoom probably goes into a regulator that reduces the 12V into a lower voltage that charges the Xoom.
gbenj said:
My HTC charger outputs from the AC adapter to microusb at 5V and 1.0A, which is as high as I've seen with other phones and chargers.
The Xoom charger appears to output 12V at 1.5A.
I'm no electrician but that does seem like a pretty big difference. 140% greater in and 50% greater respectively.
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I don't see how you see it as whining, we're just figuring out how to get things we want ourselves instead of waiting for the manufacturer to do it for us
Most of XDA's reader probably have some kind of techincal/engineering/IT/industrial background. Nothing wrong with pooling our talents to solve manufacturers' shortcomings.
USB Charging
Just tried to charge it VIA USB and wall charger with USB port & this is the result.
Well, I'll need to ask this question: do any of you guys know if Acer is going to bless us with a USB to proprietary connector for our Iconias?
Look, I've accepted the length of the power cord. One, it is what it is and two I can always go and buy an after market adapter which could be longer. Fine. What is unforgivable, to me, is that I need an AC plug and I can't use the myriad (at least three) AC to USB plugs that I have to charge my unit. Heck, I can even use my wife's iPad adapter to charge my EVO in a pinch.
It can be done as I assume that the docking station Acer sells can charge the unit. Besides if Sammy, Toshiba and Asus have similar things why can't Acer? If they come up with something like this they'll (to me) boost the value of my Iconia a bit: I can use USB and the other adapter to charge it.
C'mon Acer: get in gear!
I'm not 100% sure I understand the question, but I'll take a stab anyway.
It is impossible to charge through USB to the A500, either through the USB ports or the dock connector. USB only has a 5v signal on it, and I believe it's max current capacity is 500ma (per standard), whereas the A500 needs 12v and 1.5a of current.
Does that help?
USB 2.0 standard allows maximum output of 1.5 amperes, or 1.8 amps on a dedicated charge port with a special cable (e.g. cannot carry data but can only charge, I have never seen one by the way) at 5 volts. These 1.5 and 1.8 amps are for USB chargers by the way, computer USB 2 ports are all rated to a max. of 0.5 amps.
A500 needs 1.5 amps at 12 volts, which is roughly 2 times more current than the usb standard (Watts = Voltage x Amps), e.g. acer power brick supplies 18 watts vs a dedicated USB charger can only supply 9 watts at 1.5 amps. Most of the phone chargers that use USB cables are around 1 amp, making their max. output 5 watts vs 18 that acer needs.
In summary, it is not possible to charge A500 via USB.
No, no, no....
I think I explained myself poorly.
You guys know that the on the bottom of the Iconia there's a connector; a proprietary connector. I assume that the unit can be recharged through there. So what I was saying is that there should be a cable that ends in that proprietary connector on one side, and on the other on a standard USB connector so that it can be charged. Very much like the iPad or the Samsung Galaxy.
I should have mentioned the word 'proprietary'
citizenklaw said:
I think I explained myself poorly.
You guys know that the on the bottom of the Iconia there's a connector; a proprietary connector. I assume that the unit can be recharged through there. So what I was saying is that there should be a cable that ends in that proprietary connector on one side, and on the other on a standard USB connector so that it can be charged. Very much like the iPad or the Samsung Galaxy.
I should have mentioned the word 'proprietary'
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If I had read your original post carefully I would have noticed that
That would work if they made a 5 volt, 4 amp charger with removable usb cable on the charger end as you suggested, and we would be able to use that charger for everything else as well.
Well...
I'm keeping my fingers crossed.
Not to rain on your wishing parade, but it wouldn't work, even with the dock connector adapter. The batteries in these tablets are 7.3 volt Li-Po packs(I think thats the voltage at least) so they require at least 9 volts to charge them. Thats why the docks that Acer makes for these use the same power supply as the tablets themselves. Without high enough voltage, it wouldn't charge. I guess you could make a charger that would plug into the connector on the bottom, but you would end up having to use the same old power supply to get it to do anything. Conceivably you could make a double USB plug on the other end wired in series, that would bump it to 10 volts/500 ma and it would work as a trickle charger of sorts.
I tried swapping out the USB cable that came with my nexus 7 with a longer usb cable (still using the same charger though edit: by that, i mean the ASUS charger that came with the N7). It doesn't seem to be charging though, even though it says 'charging' on the screen. When i was using the nexus 7 while plugged in, i actually lost 1% charge after using it for like 30 or so minutes.
I think i grabbed this cable off Ebay. It had no trouble charging my phone. Are there different grades of USB cables or something?
By same charger do you mean the one it came with? The 2 amps charger. Sorry I had to clear that bit up. I think longer cables creates more resistence but I'm not sure if the cable length is significant enough stop charging. I have no idea about grades of USB cables though maybe someone can elaborate on that.
Summerfly said:
By same charger do you mean the one it came with? The 2 amps charger. Sorry I had to clear that bit up. I think longer cables creates more resistence but I'm not sure if the cable length is significant enough stop charging. I have no idea about grades of USB cables though maybe someone can elaborate on that.
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Yes, the ASUS charger it came with, i plugged in the 6 foot microusb cable i bought off ebay into it.
MFister said:
Yes, the ASUS charger it came with, i plugged in the 6 foot microusb cable i bought off ebay into it.
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Okay, 6 foot cable doesn't sound excessively long. I have to ask what were you doing on it while charging and what brightness setting was the screen at. Maybe you were draining more power than the charger can provide?
This is pretty common. The stock cable has larger conductors, as I assume other 2 amp chargers come with, and standard cables are sensed somehow and charging current is limited. Try finding a 22awg cable, I think it will work.
I use a USB extender since I don't have any outlets near my bed. I use a cable rated for USB 2.0 and haven't had any problems. I have had problems with cables that aren't. The Motorola USB cables are rated for 2.0 and they all work fine for me with no problems.
burpootus said:
This is pretty common. The stock cable has larger conductors, as I assume other 2 amp chargers come with, and standard cables are sensed somehow and charging current is limited. Try finding a 22awg cable, I think it will work.
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Thanks, i assume this cable that's 28/24 awg would work?
http://www.monoprice.com/products/p...=10303&cs_id=1030307&p_id=8643&seq=1&format=2
I use a cable extender, but I insert the original stock cable into the tablet (not the charger). It appears to recognise that and charge at the correct rate.
I've tried using a usb extender to charge with the asus charger and the Asus USB cable and checking with battery graph it charges much slower compared to using just the Asus cable.
People with eyesight better than mine will see that the micro USB socket has 5 pins and the Nexus looks at the 5th pin to decide what is connected and what the connected device is allowed to do. The pin can be grounded, not connected (floating) or can be connected to ground via I think 3 fixed resistances. Google for USB on the go. I think that is the standard adopted by Asus and the cable doesn't comply.
I'm using a nook 1/2 cable I got with a car charger for the nooktablet
It works and is longer then the stock cable it came with.
Sent from my Nexus 7 using Tapatalk 2
EE here. I just ran into this issue recently, so I'll share what I learned. Grab a multimeter and measure the resistance of the cable. Check all 4 pins just in case one of them is worse than another.
In my case, I had a really horrible USB extension cable. It measured about 4 Ohms. 4 Ohms is low enough for a multimeter to pass a continuity test, but do out the math:
V = I * R
V = 2A * 8 Ohms (4 Ohms on VCC, 4 Ohms back on GND)
V = 16V.
16 volts?? Where does 16V come from? Short answer: It doesn't. If 2A were actually flowing, the USB cable would have a 16V drop across it. It doesn't though, which tells us that 2A is not flowing. 1A is also not flowing, since that would still be 8V.
0.5 Ohms is a good estimate for a MAXIMUM resistance for a USB charging cable. That's a 1V drop at 2A, meaning the phone is only getting ~4V. That explains why the USB cable that comes with the Nexus 7 is so darn short - it comes in at around 0.1 Ohms (or perhaps less, that's about the limit of what I can accurately measure)
Wanted to get a longer USB cable that will work the Asus adapter, any links?
Thanks.
came across this thread while investigating a strange thing in charging my 4400mah extended battery of my s3.
I have a 5v 1A stock samsung charger with an extension cable i was always using to charge my old phones with a less capacity battery (mugen 3200mah)
This night i spent i wasnt ble to get a full charge from 5% to 100% in 8 hours and this sounds more than strange, but yet understandable.
i will try timings with the stock cable without extension and i'll come back...
Whats the deal here? Anyone find any other cables that work? If I use a monoprice premium cable with a 1 amp car charger with bluetooth and music going it won't charge. But if I use the same car charger and use the OEM LG cord that came with the phone the phone charges fine. Same thing in the house plugged in with the stock charger base. Its super slow unless you use the OEM cable.
There is a HUGE thread about this.
I think we've narrowed it down to the AWG thickness of the cable. The Stock Cable is really thick and able to carry the voltage properly. Using another cable with thinner wires, it can't provide enough juice.
But there is a huge thread on this already.
http://forum.xda-developers.com/showthread.php?t=2460881
GTvert90 said:
f I use a monoprice premium cable with a 1 amp car charger with bluetooth and music going it won't charge.
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The new chargers are 1.8A vs the old 1A charger. Less amperage = Less power, that is why it is slow charging. The width of a cable can limit the amount of amperage passed, so for 1A you can expect a thinner cable.