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I'm having problems with kaiser charging when using HSDPA and even slow connections like 3G and EDGE.
Problem is that it charges for about 20-30 minutes (connected to a powered 1Amp USB hub or even with AC charger), then charging light goes off and battery power starts to drop by about 5% every 20-30 minutes.
Have anyone tried 2Amp chargers? It seems like it may be the problem with kaiser itself, since it charges itself but then just stops and will not charge itself until I soft-reset it.
PS: it gets kinda warm, but I wouldn't call it hot. Dunno if its related to temperature.
Any ideas?
Am I the only one with this problem? If so, maybe I should return the phone and exchange it for a working unit?
No, I have the same problem here.
When I use my kaiser in the car (usually navigating) the orange charge light initially lights up, but after a short period goes out. When I disconect and connect the USB-cable, the light temporarily comes on again.
I am using a 1A car charger. I do notice the charger feels a bit hot when in use, so maybe the kaiser is drawing more power than allowed? I can imagine the charger overheating which causes the voltage to drop. Which probably causes the kaiser to stop using USB power. But this is all speculation.
I am planning to use a 5A voltage regulator to 'upgrade' the USB charger, and see if this solves the problem.
--After a bit more reading, I found some info about the kaiser detecting if it is connected to a charger or a USB host device, and regulating it's maximum charge power accordingly. So I will try a modified USB cable to let the kaiser know it can get 1000mA from the car charger.
It's not the USB charger. I have 2A and 3A Olympus Camera chargers that I modified to use as a USB charger. Also cheaper 1A AC chargers. I thought the Olympus chargers would be perfect, because they were high amperage, and built solidly. I had the same charge problems with the TyTn II, and an iPod Nano. They would either charge partially and then stop, or not charge right away, but the charge light would come on after awhile. But still only partially charge.
My guess is that the chargers that work may have a load added in, so that the switching regulator will turn on with any additional load from the device, and stay on. I never found any information on this, though.
What does work: The USB chargers made for any PDA phone. Apple iPod chargers. I bought an 800ma iPod charger (probably a clone). It's a small white cube, with a USB outlet, and interchangeable AC plugs. It charges the Nano, and the TyTn II OK. The Nano last for a week now, instead of 2 days. The TyTn II starts charging right away, and stays charging. So whatever the Apple USB chargers do, they do work.
A thought for the car is to get a car charger made for the iPod, and see if that may work.
To be more accurate, the iPod charger starts charging the TyTn II right away, and the charge light stays lit. I've not actually done a controlled test on it. Just charged for awhile, and verified that the charge light comes on right away, and stays on. Everything looks normal, though. I will try a more controlled test, and post the resutls.
please keep us posted. I've also contaced HTC support about this, I'm waiting the response. Once I found out I will post here.
Hopefully iys not a ksier limitation.
Test results.
Battery at
- 61%, Display off while charging
- 83% - after 70 mins of charging. Then stopped, as was going out.
Started again at:
- 88%, Display off
- 100% - after 60 mins. A little shorter, probably, as I missed when the charge light went green.
I believe the PDA will fast charge up to around 80%, and then slow charge for the remainder. That would explain why it takes 60 mins to charge from 88% to 100%.
So, the iPod charger works great for a PDA, and will start charging right away when it is connected, and it will charge to 100% full charge. It is not the PDA that is stopping the charging. It just has special requirements that only some chargers can handle, so you have to get either a charger built for a PDA, or something like the iPod charger.
So it works quite well as a general purpose charger for iPods, and for the TyTn II, and probably anything that uses a USB charger. It is small, with interchangeable AC plugs. A good travel/general purpose charger. I can bring just this, and different cables for different devices. Phone, MP3, etc.
It is labeled Input:100-240V, Output 5V 1A
Looks like:
Apple MA592LL/A iPod USB Power Adapter
Just as an aside, I have a lithium battery pack 2 7/8" x 2 1/8" x 1/2" thick. It is rated at 2400mAh, input 5V, through a built in retractable USB plug. Output is 5V 450mAh through a female USB plug. Just extend the USB male plug and plug into any USB source to charge it. It works quite well as a small portable battery pack to power/charge a PDA if using GPS steadily. It's flat, and easy to carry.
And it is quite cheap.
ttt123, thanks for your info. I guess I need to get an iPod charger then.
What exactly is the scoop on this? Is it that they overpower the charging circuit (everyone says they charge the phones faster)? Is there a way to tell you're about to do damage?
I don't use the car charger that came with my Kaiser, I have several generic chargers which all work just fine. However I noticed that when running GPS, although the charge light was on, the battery wouldn't really charge. It wouldn't discharge either, I put it up to the extra drain on the phone's power system.
The other day though, my phone... stopped charging? I was driving (GPS) and the phone suddenly beeped a critical battery warning, the charge light was off... but the power was plugged in and the charger's power light in the cigarette socket was on. It WAS making a connection to the phone: if I unplugged it the screen would go dimmer, if I plugged it back in it would get brighter. But it still seemed to be running off the battery, which was draining regardless. The moment I got to my destination, it all powered off. Is this a forewarning of darker circumstances to come?
from what I've read you should not be using generic chargers. The amperage could differ. Therefore, if the electricity in your vehicle spikes you could be riding with a paper weight.
In addition, it is common that your device will not charge (nor discharge) while running your gps application. I play monopoly often while my phone is in the charger and my device usually doesn't charge while I am playing.
Also, I think the pinout on generic USB chargers are different. The ones that are for Moto Razr / Blackberry phones dont work to charge the phones ( as I have a work blackberry and tried it) It didnt hurt my phone, however it just didnt charge. I have heard of others damaging but if its not made for the kaiser, I wouldn't try it.
I've never had access to Moto Razr / Blackberry chargers. While I can't speak for those, I know generic USB chargers would have exactly the same pinout as the stock Kaiser charger. The amperage supplied may indeed differ, I think that might have explained my issue above. It was almost like the charge circuit 'gave up' since the phone was demanding as much/more power as it was getting.
CrArc said:
I've never had access to Moto Razr / Blackberry chargers. While I can't speak for those, I know generic USB chargers would have exactly the same pinout as the stock Kaiser charger. The amperage supplied may indeed differ, I think that might have explained my issue above. It was almost like the charge circuit 'gave up' since the phone was demanding as much/more power as it was getting.
Click to expand...
Click to collapse
My razr charger works perfect with my tilt.. (MOTOROLLA branded - not generic)
Ditto on the motorola razr charger;Have an old razr charger I use it for travelling instead of unplugging my original;works fine!!
+2 on the Motorola branded car charger...charges my Tilt just fine. Now I'm paranoid, though...
CrArc said:
What exactly is the scoop on this? Is it that they overpower the charging circuit (everyone says they charge the phones faster)? Is there a way to tell you're about to do damage?
I don't use the car charger that came with my Kaiser, I have several generic chargers which all work just fine. However I noticed that when running GPS, although the charge light was on, the battery wouldn't really charge. It wouldn't discharge either, I put it up to the extra drain on the phone's power system.
The other day though, my phone... stopped charging? I was driving (GPS) and the phone suddenly beeped a critical battery warning, the charge light was off... but the power was plugged in and the charger's power light in the cigarette socket was on. It WAS making a connection to the phone: if I unplugged it the screen would go dimmer, if I plugged it back in it would get brighter. But it still seemed to be running off the battery, which was draining regardless. The moment I got to my destination, it all powered off. Is this a forewarning of darker circumstances to come?
Click to expand...
Click to collapse
That is the exact same thing I am experiencing with my Tilt.
Tilt is charging from a generic car-to-USB and USB cable.
I start TomTom.
Charging works fine for a while.
Then suddenly the charging stops and the battery is drained.
I found only two ways to get it to charge again:
1. Turn off device with TomTom charging; hold Tilt against cool air flowing from AC; plug into charger (while still off) ... then the phone turns on and charges.
2. Take out the battery; put it back in ... start phone.
It does seem that either the phone can draw power faster than a USB charger can supply it or the use of wifi and gps whilst charging overheats it. I particularly see this behavior when I'm running tomtom and navizon. The phone seems to remain charging longer in cooler weather or if I point an air vent at it. My current no wifi woes started after an occurrence of just this behaviour the other day.
RAZR chargers don't have enough current and it doesn't keep a positive charge when using the GPS. It says it's charging but ultimately it goes down. Sometimes it stops charging and I had to unplug it and plug it back in. Use a charger made for the Kaiser. The charger from my brother's bluetooth GPS works fine though.
I have a generic USB cigar lighter adapter which I have been using to power mine with no problem. The only way I can see a charger frying a phone is if there is a voltage spike that isn't regulated.
The charger needs to be rated with an output of 5v 2amps which is what the electric charger is rated at. Bought one off ebay for $6. Most car chargers are rated quite a bit lower (400ma).
As the previous post states, some chargers are rated at under 500ma. This is not enough to change the Kaiser... I find that the Blackberry charger works fine, but sometimes takes a very long time to charge as the current isn't quite enough. I have a generic one at about 1000ma and that works fine.
USB from a PC is normally 500ma sustained.
I think there's another thread or 2 about this somewhere. I've been having the same problem with the Kaiser not charging via generic and razr car chargers.
After seeing the other thread I bought an HTC charger from ebay - at least it looks like one and is advertised as one! The sticker on the 'real' HTC charger only says 0.5 amp (same as the others are rated), but charges no problem with TomTom going.
I tried measuring the current using different chargers and PowerGuard and I think there is a definite difference (although not an easy thing to interpret). I notice the cable is significantly heavier on the real HTC charger (also coiled and tends to drag the phone from where I mount it a little). Others have said the pinouts are different too.
I looked for a 2amp charger but couldn't find one (if anyone knows a source?).
It's an intriguing problem but a 'real' HTC charger seems to fix it.
The other thread: http://forum.xda-developers.com/showthread.php?t=406771
There were a range of brodit car mounts with built-in chargers that bricked the kaiser. I bought one and it instantly blew it's fuse. I replace the fuse and it blew my kaiser up instead.
Assuming it was the kaiser I had it replaced, only for the charger to blow it up again.
Since then I contacted dsldevelopments (UK Distributor) who replaced it with an updated model. I have not had any issues after that.
I had this problem (Kaiser not charging in the car when GPS is on) and resolved it totally by getting the offical HTC car charger. Although output is 0.5A it is rated to 2A - my previous generic car charger was only rated to one amp and that would work fine as long I wasn't using GPS but once I ran GPS it just couldn't cope. Definately resolved this problem with the official HTC car charger (got mine of flea bay for £8)
cheers
Barney
I've had no problem with designed-for-Moto chargers and ones specifically designed to charge over USB from a dumb charger.
The problem is that drawing more than 100 mA without negotiating a connection with a PC violates the USB specification. Many manufacturers have gotten around this by finding other ways to signal the presence of a "dumb" charger, telling the phone it can draw more than 100 mA.
In the case of Mini-USB devices like the Motos, Blackberries, and HTC devices, the Mini-USB connector has a fifth pin that is normally not connected. If the charger plug grounds this pin, it signals to the device that it is permitted to draw more than 100 mA without a PC connection.
If you get a charger that does not ground this pin, an HTC device will not charge rapidly, if at all. (Typically only charges slowly when screen is off). This is why you get two cables when you order a single MiniSync from BoxWave, for example. They give you one "Sync and charge from PC" cable (no pin grounded) and one "Charge only" cable (pin grounded for dumb chargers). (If the pin is grounded it interferes with data communications for most devices.)
I use a motorola charger, which is fine if you do not use GPS.
when I use the GPS after some time the battery is very hot and stops load, but if I put the cell in front of the AC, just cools again to load.
I think the problem is due to protection from overheating battery
Belkin Charger
I grabbed a Belkin charger for my KRAZR/RAZR phones and it seems to work just fine, even with GPS running. My official Moto one also works fine with the tilt in GPS mode.
I do notice, though, that no matter what I'm using to charge it with, with GPS it gets hot. Since Li-Ion batteries are supposed to stop charging at a certain temp, it's possible that the combination of a lower grade charger and the heat generated by using GPS/WiFi/Cell at the same time (or any combo of the three), might be the issue.
I think this is pretty unique
http://tinyurl.com/yztqtrq
A mains charger with multiple plus adapters BUT...and here is the clever bit, the mains charger has a small lithium ion battery built in so that whilst you are charging your HD2...it's also charging the internal battery. That means if you are away from a power source, you can still charge your HD2 by flicking the switch on the side of the mains unit and it then charges your HD2.
I haven't had it long enough yet to see how many charges it'll do, but it seems like a good bit of kit and the only charging kit I'll ever need. Heck, it even comes with two USB ports in the top, (you can actually charge TWO devices at the same time) plus a USB charge cable and a car charger plug too.
Nice, but what's the battery capacity there? It looks a bit smallish.
Batrtery capacity
Looking at the battery it's a 3.7v, 1000mAh ... 'BL-5C' which I think is battery for some Nokia phones.
..you don't use the smaller 'emergency' battery actually in your HD2, you just plug your HD2 into the charger as normal, flick a switch on the charger and it uses the juice in the emergency battery to charge your HD2. So this means that even if you are away from mains power, you can still charge your device
simples...
1000 mAH is too little, alas. Otherwise I'd get a couple of those.
Too little...?
Hiya
Electricity isn't my strong point....but I don't get why you say 'it's too little'. I've been charging my HD2 using the device and it seems OK. Did I confuse you? The 1000 doesn't go *IN* the HD2...it stays in the charging unit and charges it form there...
stevep said:
I think this is pretty unique
http://tinyurl.com/yztqtrq
A mains charger with multiple plus adapters BUT...and here is the clever bit, the mains charger has a small lithium ion battery built in so that whilst you are charging your HD2...it's also charging the internal battery. That means if you are away from a power source, you can still charge your HD2 by flicking the switch on the side of the mains unit and it then charges your HD2.
I haven't had it long enough yet to see how many charges it'll do, but it seems like a good bit of kit and the only charging kit I'll ever need. Heck, it even comes with two USB ports in the top, (you can actually charge TWO devices at the same time) plus a USB charge cable and a car charger plug too.
Click to expand...
Click to collapse
Great find! The whole package is actually as cheap as a cheap non-OEM HD2 battery
stevep said:
The 1000 doesn't go *IN* the HD2...it stays in the charging unit and charges it form there...
Click to expand...
Click to collapse
Yeah but that doesn't matter - surely a 1000 mAh battery will not be able to fully charge the HD2's 1230 mAh battery?
In fact, it would probably be better if the secondary battery did go into the HD2 as you're sure to lose some of the power by way of heat etc during the charging.
I must say i like the car charging aspect. If you find yourself low in the morning, you can charge while you driving, and take it with into work (or anywhere without having to plug in) and finnish it off. Traveling time is not usually sufficient to give a decent charge.
You can then replenish the small battery on the way home. Makes sense.
I got one of these but am having some trouble using the sync & charge cable with a PC. Although the phone will charge when plugged in, t I'm not asked whether I want to connect via ActiveSync, disk drive, etc. and I get driver errors on the PC. Do I have to do something special to use the cable with a PC?
I think its a charging cable only and not a data transfer cable.
I got the 16GB Touchpad few days ago and since i got the one with an american charger i cant charge it yet (till i get the traveler kit).
My actual problem is that it doesn't charge through the USB port too. I left it for like 24-30 hours charging through the USB port (with the cable that came with the touchpad) and when i try to turn it on, it shows me an icon of an empty battery.
Is my usb cable problematic or it just that the touchpad cant charge through the usb port from a PC?
ps: every time i plug the usb it get a message telling "to reliably charge please use the charger and cable that came with this device"
I have the same issue with a 32 GB one. I received it brand new, factory sealed today and it is going back to HP. I called HP, the cable is fine, works with my HTC phone, it's the USB port on the Touchpad, it's loose and losses connection. HP is sending a box with prepaid shipping label and doing a warranty repair.
I really love the Touchpad and I am a bit disappointed with receiving a new device with a loose USB port. HP has great support and I can't wait until I get it back.
Sent from my HTC Sensation 4G using Tapatalk
Unfortunately thats not an option for me (returning it to touchpad), since i bought it from Ebay (thats the only way possible for me to buy a touchpad from my country).
You had the same issue with the charger plugged in the usb cable as well?
What sort of power source do you use, if not the charger.
I've tried to use a computer, but it does not look like it's charging, but data transfer work.
I tried with an iphone charger, that sort of work. It complains about not getting enough power (iphone charger is 5,0V while the hp charger is 5,2V)
Bottom line. Use the original charger, just buy an us adapter. It works great.
There is another thread here sonewere discussing chargers for non US owners.
Sent from my M9 using Tapatalk
Jon (aka nle) said:
What sort of power source do you use, if not the charger.
I've tried to use a computer, but it does not look like it's charging, but data transfer work.
I tried with an iphone charger, that sort of work. It complains about not getting enough power (iphone charger is 5,0V while the hp charger is 5,2V)
Bottom line. Use the original charger, just buy an us adapter. It works great.
There is another thread here sonewere discussing chargers for non US owners.
Sent from my M9 using Tapatalk
Click to expand...
Click to collapse
Im trying to charge it through my PC using the original cable that was in the box (tried it in a USB 2.0 port) and im getting the 'try a reliable recharging source like the USB cable and the charger that came with your touchpad'.
I also tried charging it with a 5.0V 200mA phone charger but it didnt work either.
Shouldnt it charge even a bit with the cable? im trying to charge it for 2 days now
Varemenos said:
Unfortunately thats not an option for me (returning it to touchpad), since i bought it from Ebay (thats the only way possible for me to buy a touchpad from my country).
You had the same issue with the charger plugged in the usb cable as well?
Click to expand...
Click to collapse
Yes, tried the wall charger, then pc, a different usb cable, all had the same result. When I plugged in I could feel the USB port loose in the Touchpad itself, it had a bit of play and if I played gently on it, it would begin to charge or connect to the pc. When i let go, it disconnected from my pc and then gave me the charging error message. I purchased mine from an e bay store and it has a warranty for 1 year.
I would be happy to help you with yours, if you want to ship it to the US, it has a warranty from the factory. Pm me if you'd like help. I am certain that shipping to and.from US could be costly but I am willing to help.
Sent from my HTC Sensation 4G using Tapatalk
Mine will only will charge from official HP chargers. This is much like my old iPhone 3g before all the generic manufacturers caught up. I suspect that the voltage and amp requirements are tighter than the USB specification, so it will be a crap shoot if you use non HP chargers.
With that said, HP has 30% off all touchpad accessories right now. Combine it with the cupon SAVE15HP
-W
Sent from my I897 using XDA App
wpp105 said:
With that said, HP has 30% off all touchpad accessories right now. Combine it with the cupon SAVE15HP
Click to expand...
Click to collapse
Ya unfortunatelly i could order anything since i dont live in the US/UK regions
Varemenos said:
Ya unfortunatelly i could order anything since i dont live in the US/UK regions
Click to expand...
Click to collapse
Don't worry over that, I can get what you need and ship it to you.
Also, in speaking to HP, any USB charger in the US works, they're considered universal.
Sent from my HTC Sensation 4G using Tapatalk
you cant charge the touchpad using a computers usb ports. it doesnt draw enough power. the voltage of the charger doesnt really matter, it needs at least 2 amps or it wont charge the touchpad. cell phone chargers usually only draw 1 amp or less and usb ports only .5 amps.
cachookaman said:
you cant charge the touchpad using a computers usb ports. it doesnt draw enough power. the voltage of the charger doesnt really matter, it needs at least 2 amps or it wont charge the touchpad. cell phone chargers usually only draw 1 amp or less and usb ports only .5 amps.
Click to expand...
Click to collapse
That is absolutely not the case.
I have only charged mine once with the AC-USB thing and I have been using it since I got it the first day of the sale. I use mine all day long and only charge it occasionally via USB to PC connection. I use the original cable from HP and another one from my Samsung Mythic (work and home).
The message that you get when you plug it in is misleading but normal on a stock TP. However there is a patch in PreWare that changes it to just default to charge and not bug you. Anyone who intends to use this thing at all with WebOS needs to get PreWare installed. In fact, some time spent at precentral.net would benefit any new owners. You will learn A LOT more about these little jewels. I spent a few hours reading stickies and interesting threads and learned a great deal.
If it is really plugged in (and you will know because your PC will tell you) and you get no charge, you have a problem. It should charge on or off while plugged in - mine does.
nunjabusiness said:
That is absolutely not the case.
I have only charged mine once with the AC-USB thing and I have been using it since I got it the first day of the sale. I use mine all day long and only charge it occasionally via USB to PC connection. I use the original cable from HP and another one from my Samsung Mythic (work and home).
The message that you get when you plug it in is misleading but normal on a stock TP. However there is a patch in PreWare that changes it to just default to charge and not bug you. Anyone who intends to use this thing at all with WebOS needs to get PreWare installed. In fact, some time spent at precentral.net would benefit any new owners. You will learn A LOT more about these little jewels. I spent a few hours reading stickies and interesting threads and learned a great deal.
If it is really plugged in (and you will know because your PC will tell you) and you get no charge, you have a problem. It should charge on or off while plugged in - mine does.
Click to expand...
Click to collapse
The problem is, its plugged, i get the warning but its not charging at all (while the touchpad is turned out cause its out of battery the past 2 days).
Varemenos said:
The problem is, its plugged, i get the warning but its not charging at all (while the touchpad is turned out cause its out of battery the past 2 days).
Click to expand...
Click to collapse
Now to be completely honest - the first charge I made out of the box was with the AC adapter and I left it in overnight like I had been told.
But since then I have never used the AC plug and I have let it get down to about 20% or so but no lower.
It very well may be that from a DEAD state, it requires the extra amps to jump start it, but as long as you have that initial charge it is covered by the lower amperage of the direct USB-to-PC connection. I'm guessing it came with a fair charge and you burned through it without ever plugging it in to the USB.
Bear in mind that not ALL USB ports on a PC are powered the same either. Older USB 1.0 and 1.1 are crap for power. Front or top-mount ones also may not have as much juice as the ones in the back directly off the motherboard. Look at portable hard drives, some come with a double-header cable to use two low-powered ports. I know my top-mount ones will not power my 1TB 2.5-inch drive, but the ones in the back do.
However, I am really surprised you can't pick up a standard plug in USB adapter for your country for a few dollars (equivalent) for wall. Jeez they sell them at the dollar stores here now. I don't know if a car adapter would output enough to do it but that is another idea. If you can get one, you should be able to bring it back easily enough. The 2 amp adapter does charge a lot faster.
---------- Post added at 11:15 PM ---------- Previous post was at 10:53 PM ----------
LOL, I am really in a rare mood as this question has bugged me a little. So I decided to find some straight poop. Here is the best description I have seen anywhere.
http://www.maxim-ic.com/app-notes/index.mvp/id/3241
If you don't want to read it, the gist (as I understand it) is:
At 5V, the USB ports in a PC have to be able to source (provide) at least 500 mA (.5 AMP). However, depending on how your motherboard is provisioned (MOSFETs and diodes) that is limited/controlled.
The spec though, does allow as much as 5A to be provided. In fact, 2A is not uncommon if the other ports are not loaded.
So you could try unplugging all your other USB stuff or try another computer's USB ports.
Varemenos said:
Im trying to charge it through my PC using the original cable that was in the box (tried it in a USB 2.0 port) and im getting the 'try a reliable recharging source like the USB cable and the charger that came with your touchpad'.
I also tried charging it with a 5.0V 200mA phone charger but it didnt work either.
Shouldnt it charge even a bit with the cable? im trying to charge it for 2 days now
Click to expand...
Click to collapse
Given that the HP charger has a 2A output, odds are that anything much below around 500mA isn't going to charge the device, or at least not at a rate that'll offset the drain while it's running.
The USB ports on laptops often won't supply enough current, particularly if there's other devices on the same bus. If you plug it into a powered USB hub then you should be in business as they should supply more like around 1A generally.
My Touchpad charges from my laptop USB port, however it is slow. I am getting about 8 - 10% charge per hour. The screen needs to be off though, otherwise there is no noticable charging happening.
Mine is not charging with USB laptop at all. Need to use wall charger
I have XRON VB2.8 on my two touchpads and both show battery charging symbol when they are connected to computer via USB and yes the they charge very slow.
FYI, can't remember if WebOS / Govnah tells you what the current amps being used is, but if you are on Android tools like Elixir 2 tell you how many amps you are either discharging (-) or charging (+). So depending on what you are using (wifi, bluetooth, # of widgets, running applications, screen brightness, overclocking, underclocking, etc.) YMMV on whether or not you can charge via usb connected to your computer.
So if you are discharging at a rate of -750 mA connecting to a usb port on your computer will still have you discharging at a rate of -250:
Code:
[COLOR="Red"]-750 mA[/COLOR] + 500 mA = [COLOR="Red"]-250 mA[/COLOR]
mine charges in the usb port, but only if I turn off the screen or turn off the touchpad completely. my ports only provide 500mA, and with the screen off, the touchpad draws about 50mA, so it can charge at about 450mA. With the screen on, it draws about 760mA, so even when it's plugged in the USB, it is discharging at a rate of about (760-500=260mA).
Background
Hi all, I, for a very short period of time was suffering from the problem of my phone DISCHARGING while it was charging. This made no logical sense to me until I did some research, which I will detail below.
How USB Power works (Roughly)
Firstly let's discuss USB power provisioning. Strictly speaking, the specifications say that any given USB port should provide a maximum of 500mA (or 0.5A) at 5 volts. *Don't shoot me electronics guys, I'm simplifying for ease of explanations sake*. Imagine that ampage as the actual force of the charger, how quickly it can ram power into your phone. Like the rate of flow on a pipe.
The beginning of the problem
This was all fine and dandy when all USB was really used for was Keyboards, Mice, Memory, etc, low current draw devices. Something else I should mention here is that the Ampage that a port CAN provide is not the Ampage it DOES provide - the device draws a certain Ampage and if the USB controller agrees it outputs said Ampage. Later, when USB was beginning to be used for more power hungry applications, ie External hard drives, these required more power than the port could (In theory) provide. However, most more modern motherboards/USB controllers were more than capable of supplying plenty more Ampage if it was requested. This was breaking the specification but not in any massively dangerous way so as such nothing bad happens.
This is where we get to the actual issue people are experiencing here. The Nexus 4 is a standards compliant device in the respect that it seems to only draw 500mA from any USB port no matter what it's potential, unless it's an AC Wall wart. If you're experiencing problems with wakelocks (see XDA) and other things, this causes your phone to draw more than 500mA which means your phone actually discharges while it's charging! Terrible!
This is quite easy to get around, but again I'm going into detail so let's explain how the phone tells the difference between a dumb wall wart and a USB controller. Easily! The USB controller obviously makes use of the data pins found within the USB cable, whereas a wallwart just (almost always) shorts them out. The Nexus 4 can detect this short, and as such draw more power *While still in quotation marks staying in spec*.
The root problem is not with how the N4 is charging, it's with the wakelock you're experiencing which is causing the phone to draw so much power while the screen is off. While the screen is off and the phone is in Deepsleep (A CPU state where it uses very little power) - it should draw no more than 50mA leaving 450mA for charging the battery, but you guys are probably experiencing a wakelock of some sort.
Solutions to the problem or How to break a specification for the good of mankind
The simple solution is to install this app: https://play.google.com/store/apps/details?id=com.rootuninstaller.batrsaver
This forces the device into a Deep sleep when the screen goes off by killing applications and turning off all internal chipsets that have wakelock capability, most commonly networking on the Nexus 4. This will allow your phone to charge (slowly) off USB without an issue. Another common wakelock is when the device is picked up by your desktop as a media device. The USB controller inside the Nexus 4 forces a wakelock which keeps it from charging. Stupid design, I know.
* A more hackish solution is to install Francos kernel, buy his app, and tick the Fast charging option in the kernel settings dialog. This will force the phone to think that everything is an AC adaptor and will force the phone to draw as much current as it can from the USB port (which on most modern motherboards is fine, and results in extremely quick charging).
* An even simpler solution than all this is to just use a 'USB Charging cable' - this is simply a cable that does not have the Data pins, and as such does exactly the same as what enabling USB fast charge above does. http://www.ebay.co.uk/itm/Micro-USB...487076?pt=PDA_Accessories&hash=item51a465d124
If you live near a Poundland store here in the UK they sell a 4 in one USB cable type thing which turns 1 USB port into Ipod sync connector, Nokia connector, MicroUSB and MiniUSB, and this doesn't have the data pins and as such is excellent.
One final point, an excellent app for monitoring whether your device is actually charging or not and how quickly is Current widget: https://play.google.com/store/apps/details?id=com.manor.currentwidget&hl=en
This widget will tell you how much Ampage is going into or leaving your battery. If the battery icon is green, then it's discharging, if it's black/white then it's charging. The bigger the number, the faster the discharge/charge. This is an extremely easy way to test speed of chargers too.
Recommendations
Another solution, just use an AC Wall wart - they're cheap as hell and the one supplied with the Nexus 4 is an extremely fast charging one. Shame I've gone and lost mine.
A way to roughly monitor charging current draw
I'd also recommend you install https://play.google.com/store/apps/details?id=com.manor.currentwidget&hl=en and monitor, if the battery is green while charging it's discharging and you need a more powerful charger/to figure out what's causing your phone to use so much power.
General good values in Current Widget
I generally saw a max draw of about 750mA for charging (not including draw for powering the device, the Nexus 4 can draw more power to charge and power the device) on my old Rev10 first generation Nexus 4. On my new Rev12 board I'm noticing this increase to about 850mA.
Are higher amperage chargers any benefit to anyone?
Yes and no. You will not notice faster charging unless you use your device while charging. Your nexus will draw as much power as it needs to power the phone while charging at the fastest rate. For example on the stock 1.2a charger
1200mA | 800mA goes to charging 400mA goes to powering the phone idling
Let's say you start a stability test. Your phone will obviously be using a lot more power so this will happen
1200mA | -600mA goes to charging and 1800mA goes to powering the phone stability testing
That minus value above may look strange! Let me explain. If the phone needs more power than the charger can supply, it will draw from the battery. That's the minus number.
If you have a higher ampage charger like for example a 2.5a charger
2500mA | 800mA goes to charging 400mA goes to powering the device
Stability testing
2500mA | 700mA goes to charging 1800mA goes to powering the device
Can you see the difference?
DISCLAIMER: I am not an electronics engineer nor do I claim to be, I am simply a hobbyist and this is what I've found to be the case. Please correct me if I've made any mistakes, I want to learn.
Thanks!
Thanks so much for this post. It's very helpful.
kn100 said:
Another common wakelock is when the device is picked up by your desktop as a media device. The USB controller inside the Nexus 4 forces a wakelock which keeps it from charging. Stupid design, I know.
Click to expand...
Click to collapse
This isn't true for everyone then as mine connects and charges just fine off of my laptop and desktop when connected as a media device. In fact its on my laptop right now charging, gone from 68% to 81% in about 30 minutes and it shows connected as a portable media player.
Great info! Thanks for writing this!
In certain use cases the Nexus4 discharges faster than it charges and this is a very useful guide.
I use my phone for navigation in my car and having the GPS on and the screen at high brightness
drains the battery faster than the 0.5A car chargers can supply. Car chargers rated for 2.0A work well.
I haven't tried a 'USB charging cable' with the data pins shorted, it may work as well.
-Mindroid- said:
Great info! Thanks for writing this!
In certain use cases the Nexus4 discharges faster than it charges and this is a very useful guide.
I use my phone for navigation in my car and having the GPS on and the screen at high brightness
drains the battery faster than the 0.5A car chargers can supply. Car chargers rated for 2.0A work well.
I haven't tried a 'USB charging cable' with the data pins shorted, it may work as well.
Click to expand...
Click to collapse
was over in Nexus 7 forums and the 4.2.x kernel should have solved the problem at least for having to use shorted cables. have to wait and see if 4.2.2 brings any more changes.
http://forum.xda-developers.com/showthread.php?t=1984838
Section 6 in this link is about power supplied through USB
http://en.wikipedia.org/wiki/Universal_Serial_Bus
I can't tell if we have an updated kernel allowing faster usb charging as I'm limited by the power output of the usb port in my laptop. The output (5V at 500mA max) is controlled by the laptop (USB Standards) and it doesn't matter what the phone or cable is capable of as that's the max it will give out and that's about what I'm charging at. If I had a dedicated charging port in my laptop then it would be different and I could see if its able to draw more power. I have a 1.0 amp port in my car and it does charge at the higher amperage, I would assume it would do the same thing if I had a 2 amp usb port in the car. So I think the stock kernel has the fast usb charge built in it just depends upon if you have a usb port capable of providing a faster charger, it has nothing to do with the cable as I'm using a standard unmodified micro usb cable and its able to draw the max a usb device is able to put out.
thanks
thanks for a great detailed post!!!
I have the same trouble with my N4 when I was charging while using my phone...
I find it very slow... I guess I've been spoiled by my previous iPhone (which charges fairly fast)....
i might be stating the obvious but I find the phone charged "a lot" faster when it's OFF
if you are running low with your battery and need a quick 10 min charge, just do yourself a favour by turning off your phone...
the difference is quite significant!
kzoodroid said:
This isn't true for everyone then as mine connects and charges just fine off of my laptop and desktop when connected as a media device. In fact its on my laptop right now charging, gone from 68% to 81% in about 30 minutes and it shows connected as a portable media player.
Click to expand...
Click to collapse
Yup, me too. It only discharges while charging when I am playing like NFS most wanted.
Sent from my Nexus 4 using xda app-developers app
The issue with cables is with the LG usb wall charger as the one supplied isn't capable of getting the 5 volts at 1.2 amps that the charger is rated at, mine is getting around 300 - 400 mA. The micro usb cable I have in my car and use with my laptop (for charging and data transfer) is able to handle the higher amperage, it gets around 1 amp with the LG plug. There are no specs on these cables so I can't list a definitive difference and I would assume that the cable mod in the OP might help with the LG cable. It also might just be simpler to only buy those cables capable of handling higher amperage as obviously they are out there from my experience.
The cable I'm using is an RCA coiled charging/syncing cable model AH732CBR (has data pins). The maximum I'm getting from this is about 870 mA regardless of the amperage of the usb port, I've tried a 1.0, 1.2 and 2.1 and they are all around 870 mA on current widget. I would suppose if I could find a strictly charging cable I could get higher (link to ebay in OP is outdated) but this is still 2x that which I'm getting from the LG cable supplied with the phone which only puts out 300-400 mA. Our phone also has Qualcomm's quick charge which is supposed to improve battery charging times by 40%.
http://www.droid-life.com/2013/02/1...allows-your-device-to-charge-up-to-40-faster/
How do you measure how much mA the device draw from the charger?
Sent from my Nexus 4 using Tapatalk 2
omrij said:
How do you measure how much mA the device draw from the charger?
Sent from my Nexus 4 using Tapatalk 2
Click to expand...
Click to collapse
current widget, link is in the OP
kzoodroid said:
The cable I'm using is an RCA coiled charging/syncing cable model AH732CBR (has data pins). The maximum I'm getting from this is about 870 mA regardless of the amperage of the usb port, I've tried a 1.0, 1.2 and 2.1 and they are all around 870 mA on current widget. I would suppose if I could find a strictly charging cable I could get higher (link to ebay in OP is outdated) but this is still 2x that which I'm getting from the LG cable supplied with the phone which only puts out 300-400 mA. Our phone also has Qualcomm's quick charge which is supposed to improve battery charging times by 40%.
http://www.droid-life.com/2013/02/1...allows-your-device-to-charge-up-to-40-faster/
Click to expand...
Click to collapse
Bit of a late reply but please bear in mind the Nexus will NOT draw anything more than about 800mAh from the wall for charging alone. That is the absolute max and is a hardware limit - If the cable is transmitting that and it's showing in current widget you've got a good setup. See the added section in OP for more info on higher amperage chargers.