Does using UEFI increase battery life

USB drives have a chipset that converts USB mass-storage-device commands to IDE or SATA commands, which the drive then receives. Cheap chipsets (which are the majority, I imagine) don't pass on commands correctly to the drive that aren't directly related to reading or writing data from the drive. You are kind of at the mercy of that hardware with USB enclosures.

Sounds like only the most significant bit of the that -S value is being read by the drive or controller (off (>128) = power save mode, on (<127) = high performance mode)

You might get better feature support if your system has an eSATA port. eSATA talks directly to the drive so there is no "translation" or bridging of commands needed.

In my opinion, the best thing you can do to ensure a long life for a hard drive is:

• clean power to the system, get a power-conditioning UPS
• keep the device in a room with a steady ~70 degree temperature and low-humidity
• minimize powering them on and off, but do power them down if not being used for an extended period of time
• backups, backups, backups.

I'd say put your money into a UPS and another drive for backup. Do a RAID thing if you like.

This is a common issue with Thinkpad laptops with dual batteries.

When you plug in your laptop it will start by charging BAT0 while BAT1 reports a unknown state. BAT1 will report a charging state when BAT0 is full and BAT1 actually starts charging.

You need to take this into account in your script, and combine values for BAT0 and BAT1 to have something usable :

battery_level=$(("$battery_level_0 + $battery_level_1"))
battery_max=$(("$battery_max_0 + $battery_max_1"))

battery_percent=$(("$battery_level * 100"))
battery_percent=$(("$battery_percent / $battery_max"))

Here is a full example :

#!/bin/sh

path_ac="/sys/class/power_supply/AC"
path_battery_0="/sys/class/power_supply/BAT0"
path_battery_1="/sys/class/power_supply/BAT1"

ac=0
battery_level_0=0
battery_level_1=0
battery_max_0=0
battery_max_1=0

if [ -f "$path_ac/online" ]; then
    ac=$(cat "$path_ac/online")
fi

if [ -f "$path_battery_0/energy_now" ]; then
    battery_level_0=$(cat "$path_battery_0/energy_now")
fi

if [ -f "$path_battery_0/energy_full" ]; then
    battery_max_0=$(cat "$path_battery_0/energy_full")
fi

if [ -f "$path_battery_1/energy_now" ]; then
    battery_level_1=$(cat "$path_battery_1/energy_now")
fi

if [ -f "$path_battery_1/energy_full" ]; then
    battery_max_1=$(cat "$path_battery_1/energy_full")
fi

battery_level=$(("$battery_level_0 + $battery_level_1"))
battery_max=$(("$battery_max_0 + $battery_max_1"))

battery_percent=$(("$battery_level * 100"))
battery_percent=$(("$battery_percent / $battery_max"))

if [ "$ac" -eq 1 ]; then
    plug=""

    echo "$plug $battery_percent %"
else
    if [ "$battery_percent" -gt 95 ]; then
        echo ""
    elif [ "$battery_percent" -gt 85 ]; then
        icon=""
    elif [ "$battery_percent" -gt 60 ]; then
        icon=""
    elif [ "$battery_percent" -gt 35 ]; then
        icon=""
    elif [ "$battery_percent" -gt 10 ]; then
        icon=""
    else
        icon=""
    fi

    echo "$icon $battery_percent %"
fi