Two weeks ago I went to start my '78 Granada and the battery was
completely dead. I only drive this car once a week now but I used to
drive it every day to work. I checked immediately to see if I left
anything on. Nothing was left on. I didn't leave the lights on, the
hood, trunk, and glove box were all closed so their lights were off.
The only things that always connected to the battery are the digital
clock and the am/fm cassette radio. I charged the battery and installed
it on my other car. The car started every day over a week period. I
reinstalled the battery on the Granada, which is left outside. After
driving the car about 80 miles or so, I parked in front of my house and
disconnected one battery cable. I wanted to elimintate the cold causing
the battery to discharge. After 1 week, I reconnected the battery cable
and the car started immediately. I drove another 80 miles, returned
home, and left both battery cables connected. Last Thursday, the
battery was again dead. The only thing I suspect is that this 6 year
old battery can't source the very small current to turn the digital
clock and keep the time and channels memory of the am/fm cassette radio
24 hours a day for a few days. I can disconnect the wires for the clock
The Granada is charging the battery. I connected a shunt between the
alternator and the wire that goes to it and the meter shows the charge
current. I also put a voltmeter across the battery posts and when the
engine is running I read 15 volts. With the engine off I read 12
volts. Does it sound like it is time to replace the battery?
In hot weather like we have in Vegas, batteries can die overnight.
Works fine one day, next day you go out and its dead as a doornail.
No amount of recharging or anything else will bring them back.
It's been really hot in lots of the country and when you add six
years into the mix it is possible that your battery is beyond its
If you have a dead diode in your alternator it goes like this.
You charge it, it works fine all day, you go places and it starts fine,
but when you leave it overnight its dead the next morning.
You charge, battery takes a charge, and you leave it overnight and
its dead again.
My personal experience on both problems, of course it always
happens in 105 degree weather.
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