The following takes place in a 2000 Dodge Caravan.
Alright, last night, I was dropping a friend off and I turned the car off for 5 minutes in front of her apartment with the headlights and radio on. When I went to turn the key to start the car, it made a clicking sound (closest I can describe it is like when you put a playing card between the spokes on your bike, and it makes that loud clicking sound). That's the sound of a dead battery, right? My friend said it was coming from the where the fuses are, and from the starter motor. The weird thing was that the headlights worked fine even if the car didn't start. In the end we jump started it, but I couldn't understand:
a) Is that the sound a car makes when the battery is dead?
b) Is it because of the battery?
c) Does the battery discharge faster in the winter?
d) Suppose I leave the headlights on like this several times (say 15-20 times over the last 2 months), does the battery recharge from that?
Some notes that I forgot to include:
-My dad took it to work today, and he said that the speedometer didn't work, and the odometer jumped back like 60,000km. It also didn't start in the morning.
-It was harder to start yesterday afternoon, like it took a second or two longer than usual.
-The night that the car didn't start, I noticed that if I pushed the button for the windows, the radio would turn off until I released the button.
It could be a poor ground, loose wire, etc, you know how that goes.
I know that the electrical system will act screwy if it has less than 12 volts (again, could be a ground, but in your case it sounds like it is probably the battery). Sometimes when the voltage regulators go bad, the batter light will go on as well as abs light, and numerous things won't work. Since you jumped it and it was fine seems to me your alternator is fine and your battery is failing. Best bet would be to take it out and have it tested. Batteries are certainly under more strain under cold temperatures. That's why cold cranking amps are always less than cranking amps. A battery will last longer if kept cold, but it will not put out as much voltage, etc. You slow down the ions between the lead plates, sacrificing voltage but prolonging battery life because it can't react as fast.
A. I believe the sound that you hear is the starter solenoid opening and
closing, when you turn the key to start, there is enough current to close
the starter solenoid, but as soon as it closes, the starter draws current,
but it is more than the battery can put out. this causes the current to the
solenoid to drop, and the solenoid opens. as soon as the solenoid opens,
the starter is no longer drawing currant, so the currant to the solenoid
increases, and it closes, repeat. click, click, click... this is the reason
the radio turned off. motors take considerable currant to run, and things
like solenoids, and radios are sensitive to decreased currant.
The reason the headlights worked is because they don't take nearly as much currant as the starter, just look at the size of the headlight fuse (and wire) compared to the size of the starter fuse. they might not have been as bright, but something like that is not easy to tell, and i bet they would have dimmed if you tried to open the window.
B. this is because of the battery. the battery no longer stores enough energy, so it can't put out sufficient current. (keep in mind similar symptoms can occur with a bad connection)
C. the battery doesn't discharge faster, but because it works off chemical reactions, it doesn't work as well, simply put, it can't create electricity as fast in the winter. add this to the fact that cold engine oil is thicker, and things like belts aren't as supple, causing the battery to have to work harder, when it is feeling "tired"
D. unless you are running a lot of things, like defroster, blower, lights, wipers, radio, etc. your batter should recharge rather quickly. however, if you leave the lights on for a long time, and the battery gets drained, or dead, its ability to hold a charge will be decreased. (this is assuming your charging system is functioning properly) Many vehicles now come with run down protection, which will turn the lights off if they are left on and the battery gets week, but it still is not good for the battery
Thanks! That answers everything.
be careful when testing the charging system and understand what you are doing - voltage regulation is provided through the ECM on many Chryslers.
I don't plan on testing it, everything points to it being the battery, so I'll just replace it. I don't have the tools or know how to test it.
I've seen digital multimeters on sale at Sears a few times for ~$15. It's a tool that you'll use a lot, I would definitely pick one up. You can always get the ye olde analog voltmeters for a couple bucks as well. Handy for cars as well as electronics.
You just need a multimeter? I thought you had to measure sulfur levels or
something :oops: lol.
So how would I check the battery with a multimeter?
BTW Battery was replaced, and it starts great.
I know for RVs and stuff people do tests like that, but I was talking about a basic test. See what the voltage is after the cars been sitting (should be 12+ V, correct?). If it is, I would think the battery isn't the problem. If it's low I'd start the car to see if the alternator charges it up, and see if the battery will hold a charge. My experience is limited, but this is how I would go about it.
To test with multimeter,
Turn ignition on, turn on headlights, blower motor, rear defroster, everythign electrical, check for voltage across batter, should be above 11 volts or so.
If not battery is bad.
Less than 12v is not good, but just because it reads 12 volts, doesn't mean it has enough 'umph' to crank the vehicle. A load test of the battery is the best way to check its condition. Vehicle running and accessories on, voltage should be between 12.5 and 13.5 volts the adaquately charge the battery. Poor connections can also give you false readings.
So to check the battery, I'd measure the voltage with the car and all
accessories off. It should be above 12V, right?
And to check the alternator, with the car running, and all of the accessories on, it should be above 12V, right?
to check the battery have car off, all accessories on, voltage of battery
should be above 11.5
to check alternator, start car and have all accessories on, voltage should be in the 13's or higher.