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Charging Issue

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gulfv|Post time:8-30-2016 06:23:27 View:5802|Reply:40

ramon2000| Post time 7-31-2016 23:25:49 | Show all posts
Since it seems you have a "USB Voltage/Current detector" I would test other usb cables (shorter and/or thicker) and probably the current / wattage will be higher.

Before using a USB voltage/current device I wasn't aware how much a usb cable can influence in the maximum current used in charging a device.
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marcoesse_Italy| Post time 8-1-2016 01:06:51 | Show all posts
Edited by marcoesse_Italy at 8-1-2016 10:23

more and more convinced he made the right choice
utilized immediately good quality chargerfor our Chuwi Hi12 ... 0_s00?ie=UTF8&psc=1
I already had as a spare for my Surface3
with this charger never Hi12 no problem
we use it while charging
leave download also battery up 8%
and then we load at night
never any trouble
Chuwi Hi12 uses my wife

my Chuwi Hi12 - my Surface3 - my FujitsuT901 -  my 950XL WM10 - my XIAOMI RedMiNote4 (4/64)
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LMCH| Post time 8-28-2016 15:33:51 | Show all posts
Edited by LMCH at 8-29-2016 00:35
deejay1963 replied at 8-1-2016 07:55
Also tablet not charging after 95% is windows issue not tablet hardware issue. Windows cannot correctly identify the battery hence to protect it from overcharging it shuts off the charging process after 95%, actually after windows detects a battery  voltage of 4.15 V approx.

My CHuwi hi12 don't boot up anymore after I left it connected to the charger , with no constant led light nor blinking light.

But connecting USB devices like a led light and a mouse I can verify that with a long press of the power button shuts it down
(or at least no power is available to USB devices) and with a short press it turn on again in what seems a bootstrap loader loop.

Reading other threads I guessed it was a battery problem, so I unscrewed the four T5 screws and with a plastic tool I detached
the alluminium chassis to check the battery.

Using my analog multimeter I could read  a 4.1 ... 4.2V voltage from the battery terminals
(the black and red wires connecting the battery to the mainboard).

Before leaving it to reacharge I was using Android, so it's not Windows, it  must be a firmware setting checked by the boot loader in firmware.

I've left the mouse and other USB devices that drained power connected to the tablet to see if they will drain the battery
enough to lower the detected voltage and let the tablet boot.
But so far it's 4 hours and no signs of life.

With no charger connected it should boot (or at least turn on the screen and display a message)
exactly to help discharge the battery instead of leaving it stuck in overvoltage protection loop
or at least stay in boot loop but using a peculiar led blinking sequence   (for example: short blinks and long blinks)
so it is possible to understand what's actually going on.

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technisol| Post time 8-29-2016 01:01:57 | Show all posts
Sounds to me like if it is turning on to the point where it supplies power to USB and then turning off on a power button long press that you may have a BIOS issue or an LCD screen or cable problem.  Have you tried connecting the HDMI output to a monitor or HDTV and seeing if it's an LCD or cable problem?

OTOH, I had a similar issue where I couldn't get it to show a solid or blinking charge LED with a known good charger tested with a phone.  I spent nearly 45 minutes with the charger connected trying combinations of long holding the button for 30 seconds, then holding for 6-7 to see if the screen lit with the Chuwi logo.  You may want to try the 10 seconds off then three quick presses of the power button, etc.  I finally got mine to boot and have had no issues since, but in my case the battery was at 0% so perhaps it was discharged so low it couldn't start up even with the adapter connected.  No idea how it discharged to that level unless it didn't shut off properly the night before and was either set to stay on or got stuck.  It shuts down fine now, sleeps, wakes, etc.
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LMCH| Post time 8-29-2016 05:29:36 | Show all posts
I excluded the LCD or cable issue booting from Android because it would still connect to my notebook when connected to the microUSB port, but you are right, I didn't fully tested that, I will try with an HDMI cable and a monitor in case it's booting to Windows.

By the way, when I opened mine to do the voltage test with the multimeter, I've noticed that compared to the photos of Chuwi Hi12 internals there wasn't insulating tape covering the battery terminals on the board.
In some situations that may cause a short if the alluminium back is pressed a bit too much oer it; the thermal pad nearby should help prevent it but since it was open I put some insulating tape (just enough to protect the soldered pads) to avoid future problems.
Maybe that's what caused your discharge issue, too ?
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technisol| Post time 8-29-2016 09:36:15 | Show all posts
Edited by technisol at 8-29-2016 11:36

Hmmm, I suppose that's possible, but considering the current capacity of these batteries I'd expect to see a large black spot, probably right through to the outside of the case, a heat warped aluminum rear cover, and probably have felt a lot of heat and heard a loud POPPING noise as stuff blew up/melted if that happened...

No offense, but I greatly prefer the notion that mine just failed to shut down correctly when it happened to me and stayed on with the original Chuwi keypad connected and closed that one time.  I've had similar issues in past on my Lenovo X200T when I selected shut down and then folded the display closed too soon and had it boot abnormally then next time and require a long hard press of the power button to shut it down and then needed to restart it.

Fortunately, I never had a persistent failure to boot or completely discharged battery with the Lenovo...  Perhaps the 45 minutes of hell with the Chuwi was just that it hadn't yet recharged enough to boot properly, but that the charge indicator showed nothing the entire time was odd and more than a little off-putting...
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LMCH| Post time 8-29-2016 13:36:31 | Show all posts
I checked with an HDMI cable and a tv/monitor, no video output.
It really seems it's blocked into an initial boot stage or something like that.

About the batteries (there are two of them in parallel), they both have a short-circuit and  overvoltage/undervoltage protection (that's also why some guys "restarted" the batteries by directly connect a 5V USB charger to them)
exactly to avoid them to overhead and blow-up (not to mention that a possible contact with the alluminion back shell would be temporary).

What really gets me down is that this table/2-in-1 is almost perfect ... except for these strange battery issues (mostly because it's hard to identify what's going on and how to fix it).

I suspect it's because compared to ARM cpus, Intel x86/x86-64 have a too complex power management that's nice to have on bigger hardware like anotebook with big removable batteries etc.
but on "smaller" devices it causes more problems that those it's supposed to fix ... or the implicit "fix" was to do stuff like "disconnect and replace the battery" or "press the reset button and have a full restart"
that's not available on these devices).

Anyway, I've left it discarge all day and the connected mouse light don't light up anymore,  so it should have discarged, tomorrow I will check thevoltage again and then will leave it connected to its USB charger
to see if the battery slowsly recharges (and no, I don't want to try a direct kickstart of the battery, don't have the proper tools to be ceratin it's safe).
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technisol| Post time 8-29-2016 15:51:51 | Show all posts
Good luck.  I suspect it's more likely a lack of quality control or testing prior to mass production or inattention to a bug somewhere...  considering the relatively small size of the sample we all represent vs. the number of problems reported even accounting for the notion that those with problems are more likely to post in a forum.

Don't get me wrong, I'm very happy with the value for money exchanged -as long as the problems are far and few between.  So far all of the issues I've run into beyond the crappy trackpad on the keyboards have been temporary, so I guess it's still a bargain as far as I'm concerned.  The only other thing bugging me even a little is that when running Photoshop, and using the pen, input seems more erratic when one touches the screen with their hand.  It's almost like the touch screen rejection is not quite working to filter everything out in the last few versions of Win 10 I've run -it's just not as smooth as it was with the version it arrived with.  
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DigitalMD| Post time 8-30-2016 06:17:33 | Show all posts
Edited by DigitalMD at 8-30-2016 09:19
LMCH replied at 8-29-2016 16:36
I checked with an HDMI cable and a tv/monitor, no video output.
It really seems it's blocked into an ...

Try everything you can, but this sounds like a component failure in the power supply section. I"ve seen a few of these including one that I had to return to the seller for replacement.
Symptoms are:
1. you do not see a blinking charge light or a power on light
2. it charges at about a 400ma rate.
3. The USB power on the ports turns on and off with the power button
4. tablet will not boot into Windows, Android or BIOS
This is not user repairable if this is the case, you should return it to the seller.
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DigitalMD| Post time 8-30-2016 06:23:27 | Show all posts
With the Chuwi charger and a good cable, the tablet should charge at approx. 1.75 amps while in use. This is sufficient to power the tablet while on AND charge at the same time.
Using the wrong cable will cause very slow charge rates.  
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