Bananian

AXP209 configuration at system startup

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Hi all,

I connected a Li-ion battery to my BPi. In Bananian nothing has to be changed and it simply works, this is excellent!

However, I'd like to change some charging parameters to increase lifetime of the battery. For example, lowering the charging voltage from 4.2V to 4.1V.

What is the preferred method to change those parameters? I was looking for a configuration file or a script that is used to set up the AXP209 at system startup but I did not find it.

Best regards
Simon
tkaiser  
Have you had a look at the sysfs interface to the AXP209' I2C implementation? Simply chdir to /sys/devices/platform/sunxi-i2c.0/i2c-0/ and crawl through the directories.

If there's what you need all you've to add is a line in /etc/rc.local echoing a value to the approriate sysfs pseudo-file.

Thanks tkaiser!

I somehow assumed those files only provided status information and were not for writing.
But "echo 4100000 > /sys/class/power_supply/battery/chgmicrovol" indeed does what I wanted. I checked it with the program axp209 ( see post #7 in http://forum.lemaker.org/thread- ... e_power_supply.html )

Best regards
Simon


Hi, it does not work for me! :-(

I connected a Li-Ion battery using the solder pads on my Banana Pro, next to the power supply socket, but it is not recognized. /sys/class/power_supply/battery/uevent (see below) shows that no battery is found. Switching on the BPro with only the battery connected does not work.

My Liion cell gives 3.7V when not connected. When it's connected, the voltage drops a bit. Any clues?


POWER_SUPPLY_NAME=battery
POWER_SUPPLY_MODEL_NAME=battery
POWER_SUPPLY_STATUS=Full
POWER_SUPPLY_PRESENT=0
POWER_SUPPLY_ONLINE=0
POWER_SUPPLY_HEALTH=Good
POWER_SUPPLY_TECHNOLOGY=Li-ion
POWER_SUPPLY_VOLTAGE_MAX_DESIGN=4200000
POWER_SUPPLY_VOLTAGE_MIN_DESIGN=3300
POWER_SUPPLY_VOLTAGE_NOW=0
POWER_SUPPLY_CURRENT_NOW=0
POWER_SUPPLY_ENERGY_FULL_DESIGN=3200
POWER_SUPPLY_CAPACITY=100
POWER_SUPPLY_TEMP=300

Ah, I got it to work after all! My Li-Ion cell was apparently too empty to be recognized; after charging it using an external charger I can now use+charge it in the BPro.

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