Very slow battery charging

Very slow battery charging

TechTablets Forums Cube Forums Cube iWork10 Ultimate Very slow battery charging

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This topic contains 13 replies, has 7 voices, and was last updated by  Martin Gorbush 2 years, 8 months ago.

Viewing 14 posts - 1 through 14 (of 14 total)
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  • #48098

    Matoz
    Participant
    • Posts: 9

    hello 

    I have very up normal problem the battery charg very slow from 20% to 100% in 10 h as android say

    So I tired ever thing I change the USB cable and the charger without any success

    Anybody have the same problem ? Or solution?

    #48103

    Hans Sprungfeld
    Participant
    • Posts: 199

    Buy an usb power meter like this for example

    http://www.ebay.de/itm/252324179649?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

    to test how much ampere you get.

    #48130

    Matoz
    Participant
    • Posts: 9

    Good idea thanks

    #48182

    fjen
    Participant
    • Posts: 8

    Mine takes ~5h to fully charge. It draws ~1.78A using a xiaomi 2A 5V charger. Using an other usb-c cable makes no difference.

    Doing the math:
    Battery: 3.7 V * 7.5 Ah = 27.75 Wh
    Charging: 5V * 1.78 A = 8.9 W
    27.75 Wh / 8.9 W = 3.11 hours

    Thats the minimum duration assuming 100% efficiency and no idle draw.

    #48267

    Hans Sprungfeld
    Participant
    • Posts: 199

    Yes, same here. 1.8A is the max this tablet can be charged with. So all people saying go for a 2.4A charger have no idea what they are talking about. I have noticed the followig:

    the default cable which came with my iwork10 is really bad. I have the above USB power tester, and if I bend/move the cable juuust a tiny little bit, like just really tip with my finger against the connector, the charge will go down from 1.8A to 0.5A!

    This could explain your terrible charging speeds. So the best bed is to buy a usb power tester or/and a better cable too.

    #48281

    Matoz
    Participant
    • Posts: 9

    I never used the cable came with the device ,as I remember the max time to full charge is about 5 h ,even with i tried to use different cable without any change in the result.

    I will buy the test and see

    #48299

    Dmitriy
    Participant
    • Posts: 3

    Just got my new iwork10 from banggood.
    I have 5v 1.8A with stock thick type-c cable and cheap smelly adapter 5v 2A.
    Adapter was broken after 2 hours of usage. Keep using another my old chinese 5v 2A adapter.

    Also i have bought separate cable http://www.banggood.com/1M3_3FT-USB-3_1-Type-C-Male-To-USB-2_0-A-Male-Data-Charger-Cable-for-Tablet-p-1026350.html
    With this cable i have only 5v 1A which is very bad.

    Also i have bought separate good quality Blitzwolf adapter with 2.4A and QC3.0 http://www.banggood.com/Qualcomm-Certified-BlitzWolf-BW-S6-QC3_0-2_4A-30W-Dual-USB-EU-Adapter-Charger-With-Power3S-Tech-p-1047935.html
    With good thick cable and this not cheap adapter i only have 5v 1.4A

    I am totally dissapointed. I should not buy all this accesories.
    What a big shit charge controller installed in our tablet pc!

    #48312

    Andrew W
    Participant
    • Posts: 95

    I wonder if it is hard circuitry or if it can be somehow controlled by the Kernel.

    As far as I know at least on ARM based devices charging current is controlled by the Kernel.

    I’m no linux expert to suggestr how to mod. But just because your charger *can* output 2.4 A doesn’t mean the device will accept 2.4 A letalone 2A.

    I’m sorry for your suffering but this really confirms my choice with the Cube i7 Book

    It has a dedicated 12V charging pin.

    I haven’t seen an Atom based device have a dedicated charging pin since a 3730 based Cube iWork8.

    The Cube i7 Book can also charge over USB type-C 3.1. Supporting USB PD.

    Unfortunatly the iWork10 and other USB Type C based atom devices AREN’T USB 3 nor do they support USB-PD (the standard as far as I know)

    I break so so many USB cables and I’ve broken USB connectors. So a dedicated pin is almost essential.

     

    #48313

    J
    Participant
    • Posts: 49

    If charging was controlled by the kernel then what controls charging when it is turned off

    #48317

    Andrew W
    Participant
    • Posts: 95

    That is an EXCELLENT question.

    All I know is that a lot of phones – take Galaxy Note 2 for example. You are supplied with a 2.1 A charger.

    Stock Kernel does not charge at 2.1 A…. Around release it was only ~1A. Really annoying if using video-out (mhl-HDMI) bluetooth, wifi/3g, all at the same time… Watch the battery drain.

    ***

    This being said I seem to think that it doesn’t charge as fast when off.

    ***

    There is communication between Devices and chargers by putting a resistive value across the data lines D+ D- .

    Maybe there is something in the charging circuitry that does it while off. Certaily with Samsung ARM based devices the kernel can be modded. Which is kind of cool that it can change the resistive value on the USB data lines to tell the charger to allow more current to be drawn.

    Is there a STANDARD(or at least some manufacturers ignore it) as to what that value is.

    Apple have their own value for iPads to pull 2.4 A

    Samsung have their own values too.

    Other manufacturers? No idea.

    These are also used to signal other things like OTG or if the device is docked etc.

    The Dirty Truth about USB device Charging

    *****

    I wonder if you could mod a cable with shorted data lines (with the right resistor) to supply more current.?

    Could this be risky? Maybe… I mean fundamentally it won’t change the voltage right!

    For example you can power any 12V DC device from a car battery (which could supply 300 A).

    Current supplied should only match the load am I right?  I mean sticking a multimeter on the voltage lines to work out the current would be interesting if SOMEONE did it.

    (My theory here could do with some refinement) but shorting data lines isn’t a new thing. And there is someone doing it on another (Dell) Bay Trail devices for different reason http://forum.tabletpcreview.com/threads/asus-vivotab-note-8-charging-and-usb-otg-at-the-same-time.61085/

    Good Luck

    Of course I’m not responsible for you breaking devices BUT I will take credit for your device becoming awesome 8)

     

    #48326

    Martin Gorbush
    Participant
    • Posts: 63

    If charging was controlled by the kernel then what controls charging when it is turned off

    In this tablet (and many more on Charry Trail platform) charging is handled by AXP288 PMIC made by X-Power. It can be configured by system or BIOS (or rather UEFI) as well it has some default values and can operate without enabling OS.

    Strange thing with this tablet is that PMIC configuration is different for Android and Windows (mostly in ACPI). For example constant voltage (CV) charging mode on Android is used when battery voltage reaches 4.35V and under Windows it is only 4.2V. Notice that build in Li-on battery is only rated for 4.3V as maximum. It is a shame that one cannot configure same charging parameters from the system as an user.

    Edit: Wrong PMIC name.

    #48327

    Martin Gorbush
    Participant
    • Posts: 63

     I wonder if you could mod a cable with shorted data lines (with the right resistor) to supply more current.? Could this be risky? Maybe…

    You can short data pins if you want. It will not brake the USB port. Even so it will not give you faster charging times at least if your tablet can draw more than 500mA from the power source. It is so because these data lines are probed to determine what kind of USB port is supplying power for charging the tablet. It it is data port then it will not draw more than 0.5A. If there is constant resistance less than 250Ohm between D- and D+ pins then it is dedicated charging port (DCP) which can supply more than 0.5A and PMIC will try to use so much as it is configured to do. In this tablet around 1.8A (I don’t remember if there is difference between Windows and Adroid OS). Even so when USB supplied voltage get below ~5.05V current drawn from the source will get lower than 1.8A.

    #48328

    Andrew W
    Participant
    • Posts: 95

    If charging was controlled by the kernel then what controls charging when it is turned off

    In this tablet (and many more on Charry Trail platform) charging is handled by ACT8846 PMIC made by X-Power. It can be configured by system or BIOS (or rather UEFI) as well it has some default values and can operate without enabling OS. Strange thing with this tablet is that PMIC configuration is different for Android and Windows (mostly in ACPI). For example constant voltage (CV) charging mode on Android is used when battery voltage reaches 4.35V and under Windows it is only 4.2V. Notice that build in Li-on battery is only rated for 4.3V as maximum. It is a shame that one cannot configure same charging parameters from the system as an user.

    Even with root there is no way of changing the values?

    Would this require manufacturer’s source code or something?

    I guess the question is WHY can’t you change the values. Is it some binary blob that the settings simply can’t be adjusted in?

    Android system directories and files made so much more sense back in Gingerbread 2.3 – It looked so much like linux. Framebuffers and it all made a lot more sense. Maybe this is just idealistic thinking

    #48342

    Martin Gorbush
    Participant
    • Posts: 63

    It is a shame that one cannot configure same charging parameters from the system as an user.

    Even with root there is no way of changing the values? Would this require manufacturer’s source code or something?

    If I recall correctly parameters exposed by PMIC driver (code name “Dollar Cove”) are read-only even for root user (I will check that again when I will have opportunity to connect external keyboard to this tablet). Without kernel source code it is almost impossible to change that.

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