Disable battery Charging

[alxm]

Perhaps max and trigger battery levels are already configurable - I forget the details.

Yes it is, start_capacity and stop_capacity in /etc/pandora/conf/eventmap

I set start_capacity 40 and stop_capacity 70 and rebooted, but the wall charger got the battery up to 90 (from 37) before I unplugged it. Then I plugged it in again and it kept charging, so neither capacity setting works. Is there something I'm missing?

 

[notaz]

You also need to change stop_current, which is amount of current (in uA) going into the battery. You can check your current in /sys/class/power_supply/bq27500-0/current_now while charging and choose a threshold above that (the current has to be lower than threshold for charging to stop; it's falling naturally as the battery is getting closer to full).
 

 

[levi]

If I remember correctly, current_now is in the form of current going into the battery (i.e. current received from the charger less current used for backlight/cpu etc.).  It's negative if the battery is powering the system, and positive if being charged.  If as you say, the battery accepts less current as it approaches charge, the number will only reduce in the direction of zero as it charges up.  Setting a threshold above a sampled charging current will always be greater than the current at charge levels above the tested charge level, and a fair bit below as well, so I don't see what's gained in setting it in such a manner.

What am I missing?

 

[notaz]

The monitoring chip sometimes miscalibrates wildly, so it may think the battery is 100% charged while in reality it's more like 60%, so the charge threshold was added as another way to see that charging should still go on. As alxm want charging to stop at 70%, he needs to increase the current threshold too.

 

[levi]

As so both current_now has to be below the stop_current setting *and* the estimated percentage needs to exceed the stop_capacity for it to stop?  I must admit, I didn't actually fiddle with the stop_capacity when I modified my settings.