I've made another update to my battery statistics calculation script. Version 1.2 brings a few improvements:
- The v_pct divisor is now calculated automatically from v_max and v_min, rather than using a hardcoded value.
- v_now no longer displays nonsensical values like 4.8 V.
I had hoped to use
bc to do proper floating-point arithmetic, but it seems that Kobo's version of BusyBox doesn't have it, so instead I've resorted to manipulating v_now, v_min, and v_max as strings, which avoids doing any actual arithmetic for the units conversion.
Remember that if you have the Libra Colour, you must replace:
/sys/class/power_supply/battery/
with
/sys/class/power_supply/bd71827_bat/
in order for the script to work. Other Kobo models may require greater changes, as some statistics may not be available.
Code:
# Battery Statistics Calculator 1.2 (2024-08-28) by Aleron Ives
#
# This script calculates battery statistics for the Kobo Libra 2.
# Check the contents of /sys/class/power_supply/ if you use a different
# model to ensure that the statistics you want to track are available.
#
# You can use NickelMenu to invoke this script like so:
# menu_item :main :Battery :cmd_output :500 :/mnt/onboard/.adds/battcalc.sh
# Gather the necessary statistics
meter=$(cat /sys/class/power_supply/battery/capacity)
v_now=$(cat /sys/class/power_supply/battery/voltage_now)
v_min=$(cat /sys/class/power_supply/battery/voltage_min)
v_max=$(cat /sys/class/power_supply/battery/voltage_max)
c_now=$(cat /sys/class/power_supply/battery/charge_now)
c_full=$(cat /sys/class/power_supply/battery/charge_full)
c_dfull=$(cat /sys/class/power_supply/battery/charge_full_design)
# Format the statistics
let c_now/=1000; let c_full/=1000; let c_dfull/=1000 # Convert to mAh
let charge=$c_now*100/$c_full # Calculate charge percentage from mAh
let c_health=$c_full*100/$c_dfull # Calculate health percentage from mAh
let v_div=$v_max-$v_min; let v_div/=100 # Calculate charge percentage from V
let v_pct=$v_max-$v_now; let v_pct/=$v_div # "
let v_pct=100-$v_pct # "
v_nowr=$(echo $v_now | cut -b 2-4) # Simulate floating-point arithmetic
v_now=$(echo $v_now | cut -b 1) # "
v_minr=$(echo $v_min | cut -b 2-3) # "
v_min=$(echo $v_min | cut -b 1) # "
v_maxr=$(echo $v_max | cut -b 2-3) # "
v_max=$(echo $v_max | cut -b 1) # "
# Display the results
echo Capacity: $c_now mAh / $charge% / $meter%
echo Voltage: $v_min.$v_minr V / $v_now.$v_nowr V / $v_max.$v_maxr V / $v_pct%
echo Health: $c_full mAh / $c_dfull mAh / $c_health%
If you download the attached version, remember to remove the .txt extension! The forum doesn't allow uploading text files with the .sh extension.