Python script to return a zsh-formatted string to show battery status in your prompt.

battery_prompt.py

#!/usr/bin/env python3
# -*- coding=utf-8 -*-
""" This script requires acpi to be installed """ 
import math
import subprocess
import sys

# Output
batt_info = subprocess.check_output("acpi").split(b',')
batt_info = [l.strip() for l in batt_info]
percnt = int(batt_info[1][:-1])

total_slots, slots = 10, []
if batt_info[0].split()[-1] == b'Charging':
    filled_symbol = u'▸'  
    empty_symbol = '▹'
elif batt_info[0].split()[-1] == b'Discharging':
    filled_symbol = u'◂'  
    empty_symbol = '◃'
else:
    filled_symbol = u'●'  # '●▪'
    empty_symbol = '-'  # u'\u25cb'
filled = int(math.ceil(percnt / 10.)) * filled_symbol  # u'●'
empty = int(total_slots - len(filled)) * empty_symbol  # u'\u25cb'
out = (filled + empty).encode('utf-8')

outstring = (
    b"%F{blue}"+out+b"%F{$reset_color%}" if batt_info[0].split()[-1] == b'Charging'
    else b"%F{green}"+out+b"%F{$reset_color%}" if len(filled) > 5
    else b"%F{yellow}"+out+b"%F{$reset_color%}" if len(filled) > 2
    else b"%F{red}"+out+b"%F{$reset_color%}"
)

sys.stdout.write(outstring.decode())