charger

#!/usr/bin/python3
#	koradcharger - Korad KA3005-based Li-Ion CC/CV charger
#	Copyright (C) 2020-2020 Johannes Bauer
#
#	This file is part of koradcharger.
#
#	koradcharger is free software; you can redistribute it and/or modify
#	it under the terms of the GNU General Public License as published by
#	the Free Software Foundation; this program is ONLY licensed under
#	version 3 of the License, later versions are explicitly excluded.
#
#	koradcharger is distributed in the hope that it will be useful,
#	but WITHOUT ANY WARRANTY; without even the implied warranty of
#	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#	GNU General Public License for more details.
#
#	You should have received a copy of the GNU General Public License
#	along with koradcharger; if not, write to the Free Software
#	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
#	Johannes Bauer <JohannesBauer@gmx.de>

import sys
import korad
import time
import json
from FriendlyArgumentParser import FriendlyArgumentParser

parser = FriendlyArgumentParser(description = "Korad power supply Li-Ion charging application.")
parser.add_argument("--charge-voltage", metavar = "volts", type = float, default = 4.2, help = "Specifies charging voltage. Defaults to %(default).2f V.")
parser.add_argument("--charge-current", metavar = "amps", type = float, default = 1.4, help = "Specifies charging current. Defaults to %(default).2f A.")
parser.add_argument("--cutoff-current", metavar = "amps", type = float, default = 0.06, help = "Specifies charging cutoff current. Defaults to %(default).2f A.")
parser.add_argument("--cutoff-time", metavar = "hours", type = float, default = 3, help = "Specifies charging cutoff time in hours. Defaults to %(default).1f hours.")
parser.add_argument("-l", "--logfile", metavar = "filename", help = "Specifies file to log into. By default, logging is disabled.")
parser.add_argument("-v", "--verbose", action = "count", default = 0, help = "Increases verbosity. Can be specified multiple times to increase.")
parser.add_argument("device", metavar = "device", help = "Device to connect to.")
args = parser.parse_args(sys.argv[1:])

class Logger():
	def __init__(self, logfile):
		self._logfile = logfile
		if self._logfile is None:
			self._f = None
		else:
			self._f = open(self._logfile, "a")
		self._last_flush = time.time()

	def entry(self, data):
		now = time.time()
		entry = {
			"t":		now,
			"data":		data,
		}
		print(data)
		if self._f is not None:
			print(json.dumps(entry), file = self._f)
			if now - self._last_flush > 30:
				self._f.flush()
				self._last_flush = now

	def close(self):
		if self._f is not None:
			self._f.close()

with korad.KoradConnection(args.device) as conn:
	try:
		conn.output(False)
		conn.set_v(args.charge_voltage)
		conn.set_i(args.charge_current)
		status = conn.status()
		assert(abs(status["ch1"]["vset"] - args.charge_voltage) < 1e-3)
		assert(abs(status["ch1"]["iset"] - args.charge_current) < 1e-3)

		conn.output(True)
		log = Logger(args.logfile)
		t0 = time.time()
		current_cutoff_counter = 0
		while True:
			t = time.time()
			tdiff_hrs = (t - t0) / 3600
			if tdiff_hrs >= args.cutoff_time:
				print("Cutting off because of time.")
				break

			status = conn.status()
			log.entry(status)
			if status["ch1"]["iout"] < args.cutoff_current:
				current_cutoff_counter += 1
			else:
				current_cutoff_counter = 0
			if current_cutoff_counter > 10:
				print("Cutting off because of current.")
				break
			time.sleep(1)
		log.close()
	finally:
		conn.output(False)
		log.close()