Battery meter is off! Why?

[IsmaelPR1]

The battery meter on my Ramos W13 Pro is not reading the correct battery charge. I am using the latest Finless ROM. Any ideas why this is so?

[Finless]

More info please?

What was your stock ROM version?
Is yours V2 W13 Pro?

Again... not enough info here to help you.

Bob

[IsmaelPR1]

I no longer have the stock rom, i am using your 1.5 rom, i have the v2 w13 pro

[IsmaelPR1]

Not only that but my battery life is horrible, 2 hours maybe.

[IsmaelPR1]

Hi Bob, any ideas on this issue? Basically my battery meter stays at 100% not matter what, even when the battery is almost empty it still displays 100%. I have tried calibrating it but it does nothing to help.

Thanks.

[Finless]

Mine does not have the problem but mine is a V1 not a V2. My 1.5 ROM was made fromt he stock V2 ROM so it should work for V2. Did the stock ROM do this? I would flash back to the stock ROM and see. Then I can look into it "maybe" as again my V1 does not do this so it is hard for me to fix something I cannot recreate.

Bob

[IsmaelPR1]

The problem persists no matter what rom I install

[dkjab]

Battery Fix

The problem persists no matter what rom I install

I was running on Finless V1.4 just fine and then one day had a battery meter stuck on 100%. It was obviously almost out of power as the screen started flashing on and off until I plugged it in. Regardless of how much I charged it, the meter always said 100% and would not budge.

I found a fix that AmLogic posted on a Chinese board which worked for me.
You need to be rooted, and have a terminal session open OR running an ADB shell as root.
Run your tablet as near flat as you can, then plug it in to charge while you execute the following commands.

First:

echo B8 > /sys/devices/i2c-2/2-0034/axp20_reg

Then:

echo B820 > /sys/devices/i2c-2/2-0034/axp20_reg

After that, your battery meter will show 0%. Reboot your tablet and charge it up. After a while unplug the power, then plug it in again and the meter should show its true value. If not, power off and charge while off, then power on.

This is a PITA to do if you are not LINUX or UNIX savvy (I am - its my day job...) but it did the trick for me and several others I read about. As far as I can make out, the AXP20 is a programmable voltage regulator/charger IC and it is getting confused after flashing with alternative firmware. Apparently the Ainol Aurora II tablet using the same SoC has the same issue and the above also works.

As ever, the risk is yours, and your mileage may vary. However, it did work on my tablet on the first go, and battery life is again great. I am sticking with V1.4 for now as it works for me, but maybe one day I will bring it up to V1.5

[Finless]

Hmmm thanks for this tip. But a "factory reset" should erase everything in /data and /sys thus doing what your commands do. I wish I could repeat this issue myself to investigate a better solution. But in the mean time I do understand what this is doing.

THANK YOU for posting this info!

Bob

[dkjab]

Hmmm thanks for this tip. But a "factory reset" should erase everything in /data and /sys thus doing what your commands do. I wish I could repeat this issue myself to investigate a better solution. But in the mean time I do understand what this is doing.

THANK YOU for posting this info!

Bob

You are most welcome.

I also read a factory reset can do the same thing, but I read that this only works sometimes. Perhaps the default values in the updated ROMs are off for the battery in some tablets, which might explain the problems. In which case the 2 values sent to the i2c device clear it completely and it then starts to charge properly again. I also read that some of the chargers supplied with the Ramos tablets can be a bit variable, which may also play a part (just speculation) - mine is quite noisy on its output - the DC is not as smooth as it should be.

Also, I really didn't want to have to reload the tablet again as I have it just as I want it (or rather as my 6 year old son wants it ), and yes, I could install Titanium Backup but just never got round to it

Great ROM BTW - I did donate some time back, and I encourage others to do so as I appreciate the effort you have made.

If you are interested, the scripts send data Register #34H Charge Control 2 on the AXP202 charger chip. For all you geeks out there, check out page 36 of the data sheet

http://linux-sunxi.org/images/2/20/AXP202_Datasheet_v1.0_en.pdf

[Finless]

Cool info! Thanks for sharing that. I learned something

Bob

[IsmaelPR1]

Hi, I have done both factory reset and reverted back to stock rom but my issue remains, battery stuck at 100% and since I am not a linux user.... well i am stuck here.

But thank you both for all the great work and information.

[hudini]

Step 1. your tablet must be rooted: http://ainolstore.co...ic/346-rooting/

Step 2. get any Terminal command line apps from google play: https://play.google....droidterm&hl=en

Step 3. in the Terminal apps type "su"(without quote) and [Enter] change user to root, then type the following command :

echo B8 > /sys/devices/i2c-2/2-0034/axp20_reg

Press [Enter]

echo B820 > /sys/devices/i2c-2/2-0034/axp20_reg

Press [Enter]

Step 4. at this time you can reboot your tablet and the battery will run down to 5%, then you can try to full charge your tablet to see the problem is fixed or not.

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ONLY do the following Step 5 to 6 if you still got battery stuck after Step 1 to 4

Step 5. if the problem still exist, then open the Terminal apps again and type the following command :

echo 08 > /sys/devices/i2c-2/2-0034/axp20_reg

Press [Enter]

echo 0800 > /sys/devices/i2c-2/2-0034/axp20_reg

Press [Enter]

Step 6. reboot to take effect.
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PS.

1. let your battery nearly completely discharge (for example watch some movie or play games to run out the battery), it may help to more accurate the battery percentage

2. this method are reset PMU and the softare accurate parameter, the battery will go down to 5% after reboot , no need to worry, charge up the battery to 100% is ok.

3. Aurora 2 and Elf 2 can use this method to fix the battery problem, it seem Fire and Mars can use this method too, but the path maybe different.

4. Some users on Ainol forum say that this method works, but I haven't try it yet, because I used the flash rom method to fixed my 100% battery problem. Use this method at your own risk

Good Luck!