The universal programmable Battery Guard (BG) prevents the excessive discharge of the battery (which would damage the battery) and protects electronic appliances against overvoltage. The BG-200 battery guard has an “Automatic Board System Detection”; the BG automatically detects the battery voltage (12 or 24V). The BG-200 battery guard is capable of carrying 200A continuous load and 210A transient load. There is a choice out of 10 on/off threshold voltage programs, for both 12V and 24V battery systems, which can be easily programmed.