Just replaced my alternator 2 weeks ago and know that my battery is on it’s last legs. Was -23 this morning and car was near dead. Used a jump starter but to no avail. Bought a battery blanket and plugged it in for last 5 hours. Went out to start the car and I had left the ignition on by mistake. So, hooked up the jump starter and it read good power to the battery. Tested with a voltmeter and shows power but NOTHING comes on. Can’t disengage key because the electric solenoid for the key release won’t work. Got no dash lights, headlight or anything.
Time for a new battery!
Tester
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Yup, a battery that was already on it’s way out got thrown out the door in the “wonderful” -23 temps
I agree I need a new battery. But why would I not see any power, lights, etc when I jumped it?
Because the battery was really really dead. Think of a Fellini movie where a man is beating a dead horse trying to get it to pull a cart.
Yeah, but you ought to still get stuff to light up when jumping the battery, even if your battery is toast (or even missing altogether!) Is it possible leaving the ignition on for 5 hours fried something? I know my Ford isn’t supposed to be left with the ignition on, but not running for extended periods of time (though I think that’s more of a “design flaw” with the EEC-IV system than a industry-standard warning.)
The thing is when I check the battery, there is 11volts
11 volts with no load indicates a bad battery, It should be 12.6 volts.
And when you put a load on, such as the headlights, it probably drops to close to zero.
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I agree that there should be at least dome lights (maybe dim) at 11 volts. Check voltage at the starter on the big wire, which should be straight from the battery. If 11 volts there, start checking for voltages in either the relay/fuse box under the hood, or the fuse panel under the dash.
There is a possibility that a wire is open internally, and you will need to start narrowing it down. A wiring diagram will most likely be needed to go much further.
You’d have to fully charge up the battery overnight with a battery charger to have any chance at all with an iffy battery at that temperature. Battery capacity is measured in amp hours, typically 60 amp hours is a full charge. So if your battery charger is capable of charging at 2 amps, that will take 30 hours to fully charge the battery. A 6 amp capable battery charger will take 10 hours, etc. There’s probably electronic circuits like the body computer in the car that won’t function at much less than 12.0 volts and that’s why you are seeing no activity at 11 volts and can’t get the key to disengage. Any time you have battery problems it’s a good idea as a first guess to clean the battery posts and connectors.