Ezpad 6 pro Battery problem

Ezpad 6 pro Battery problem

TechTablets Forums Jumper Discussion EZPad series Ezpad 6 pro Battery problem

This topic contains 6 replies, has 2 voices, and was last updated by  Aryan csz 3 months, 2 weeks ago.

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  • #176038

    Aryan csz
    Participant
    • Posts: 6

    My tablet is new it doesn’t power on with battery.. but only does with power cord.. since yesterday….

    I have removed the penal and check battery voltage across RED and black wire its 3.7Volts

    Is that correct rating ?

    And yellow and black wire has 6.5K ohms of resistance plz someone tell me if its correct

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    #179580

    Benjamin
    Participant
    • Posts: 42

    Connector

     ┌─────┐  
     │  v+ │ 
     │  v+ │
     │  nc │
     │  nc │  <-Cable plugs in from this side
     │ RES │
     │ GND │
     │ GND │
     └─────┘

    RES to GND is 10.01 kOhm at 24.0°C, so I guess thats an 10kOhm NTC.

    V+ to GND is when about 70% charged 7.94V

     

    Have you accedentaly measured resistance accross v+ and gnd? Because that voltage (3.7V) would be about what you should expect from a single lithium cell when depleted, not two cells in series. Since the two cells are in series to get to the 8V, you might be able to carefully lift the tape accross the battery terminals and meassure voltage of the individual cells and check if one is dead.

    Just one note: my battery connector cable has a white cable instead of an yellow one, so they might not be the same.

     

    If you plan to replace your battery i would recommend that you check out the data sheet of the charge controller which should be an MAX 17205.

    https://datasheets.maximintegrated.com/en/ds/MAX17201-MAX17215.pdf

    According to the datasheet this chip should be able to do cell balancing when the protection circuit is on the hight side of the cell (see page 29). Maybe jumper designed for that because there are more traces to the battery connector.

    If you have any news on this toppic please let me know because replacing the lithium battery is something that has to done to every tablet eventually.

    Greetings

    appswert

    #180080

    Aryan csz
    Participant
    • Posts: 6

    Thank you… 😊

    Yeah the connector is same as you shown above… and the readings as I mentioned before  its showing 3.7volts with both RED to Black Wire on multimeter…. and 6.7k of resistance block and yellow wires….

     

    As you said I’m ready to diagnose it… by removing the battery tape and measure the voltage of each battery….

     

    And I used to plug it for charging when the windows in ON (I mean booted up) and  charge it to 70 to 90%  and remove cord then shutdown it….

    Reason why I did it was if I plug charge when the system is off… the it would never turn on again…

    Somehow last time by holding power button when it was charging it booted up on battry. Latter my friend had charged it when it was OFF since then it’s not starting on battry….

     

    NoTe: my jumper Ezpad 6s pro came with 128GB of SSD and NO EMMc there is no onboard EMMc storage… I dont know may be this is reason of some Bios settings.

    Plz do assist you points 😊

    #181108

    Benjamin
    Participant
    • Posts: 42

    Hi Aryan,

    Reason why I did it was if I plug charge when the system is off… the it would never turn on again…

    I’m not realy sure what you mean. I tested how the tablet behaves with unplugged battery:

    After unplugging the internal battery and connecting the charger the orange charging led went on even though there was no battery connected/nothing to charge. So think of it more as an “external 12v supply connected” LED.  When pressing the power button in this state the tablet tries to boot three times and fails at the first two with a black screen, but does reboot automatically and after the third try it eventually works and starts up the operating system.

    When connecting the battery back to the tablet without the external powersupply the first two starups fail in the same manner as after disconnecting the battery. But after the third attemt it will sucessfully boot.

    Be careful when you do an attempt a battery replacement, an exploding lithium battery is the last thing you want, and it’s easy to accidentaly short some leads while you solder the wires.

    NoTe: my jumper Ezpad 6s pro came with 128GB of SSD and NO EMMc there is no onboard EMMc storage… I dont know may be this is reason of some Bios settings.

    Hm, they might have saved the expense of soldering a emmc chip on the board, the ssd will be faster anyway, so you won’t miss out on anything.

    Greeting

    Benjamin

    #181124

    Aryan csz
    Participant
    • Posts: 6

    I have tested cell cell they are working fine.. both batteries…. but there is problem with the protection circuit…. I don’t know how to troubleshoot it.

    #181176

    Aryan csz
    Participant
    • Posts: 6

    Guys I request someone to disconnect the battery (from board) measure the black to red voltage across connector note the voltage

    And Black to Yellow (Res) note the resistance and send me…

     

    Recommend to test it when battry is below 10%  please do send me awaiting

    #181282

    Aryan csz
    Participant
    • Posts: 6

    Probably I should only reply for this…

    After going through lot of circuit analysis

    I connected 12V bulb to discharge battery to recharge it.  Balancing circuit had a issue of mischarged…. so after draining battry 12v bulb for 3 to 4min I removed it and checked via multimeter

    Whaola… its reset to zero now the voltage is 8.4 volts  which drives tablet….

    People try on your own risk batteries may explode due to shorts be cautious…

    Thank you…. 😊

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