Car battery woes

November 19, 2008 2:09 PM

My relatively new car battery (~1 yo) seems to be giving me some troubles. Is this a sign of a weak battery or something more serious?

Ever since the weather started cooling down, I've been having some issues starting my car. Sometimes I'll turn the key and just hear a click, turn it again - click, turn it again then it'll slowly crank and eventually start. Sometimes it takes me as many as 4 or 5 turns of the key to get the thing actually cranking. It has never failed to start on me yet.

Once I'm out driving it seems fine. It'll start up fine on the first turn. It's only when the engine is completely cold that I have this issue.

The battery is only about a year old, and I'm not sure why it would start giving me problems. And why would it seem to go from not even to cranking, to eventually turning over and starting? Could this be something other than the battery? How should I go about figuring out what the issue is? I'm trying to do this on a tight budget...



Thanks

posted by pilibeen to travel & transportation (10 answers total)

You should first make sure all the connections for the battery cables are clean and tight.
posted by buggzzee23 at 2:19 PM on November 19, 2008

Start with the simple, cheap things. Check for anything left on in the car, like an interior light, radio, etc., that might drain the battery. Clean and tighten (but don't over tighten) battery connections, including the negative ground to the car. Be careful not to short the battery with your wrench. Borrow a multimeter and measure DC volts across the battery terminals when the car is running. It should be charging about 14 volts. If not, your alternator brushes may need replacing. The brushes and diodes should be less than $20 and you can replace them yourself. Could be the starter solenoid, also.
posted by weapons-grade pandemonium at 2:21 PM on November 19, 2008

From what you've described, the battery sounds like it can be charged, but it won't hold a charge. This could be the result of:
• something (like the light in the trunk or glovebox) staying on after you've shut off the ignition
• a loose alternator belt
• a faulty alternator
• a dead cell in the battery
• a faulty battery

A quick way to narrow down the source of the problem (after you've driven it so the battery is charged) is to disconnect the battery and let the car sit overnight. The next morning, reconnect the battery--if the car starts, you'll know it's not the battery and something is draining it.
posted by mattdidthat at 2:32 PM on November 19, 2008

Yep. The above info is good info (aside from the nonsense regarding your alternator). Looks for signs of corrosion on the main battery cable ends..... but it does indeed sound like the solenoid is ready to fail.

(FWIW I am a mechanic and have dealt with plenty of bad solenoids/starters).

First, make sure the battery cables are indeed TIGHT on your battery. Then, have someone try starting the car as you GENTLY tug on the cables towards the opposite ends from the battery. Does is act differently as you tug while the key is being turned?

If no effect as compared from before after trying these things, I would say the solenoid is getting ready to bid you farewell.
posted by peewinkle at 2:39 PM on November 19, 2008

Make sure your terminals are clean. If there's corrosion, you can get a little wire brush at the auto parts store for $2-3, or scrape with an old pocketknife. A little baking soda and water with help, too.

If there are plastic caps on the top of the battery, pop them off with a screwdriver and fill each compartment with distilled or deionized water. Do not use tap water. Do not let any battery contents get on you (especially your eyes) or your clothes--it is extremely caustic.
posted by neuron at 2:43 PM on November 19, 2008

This is why I don't take my cars to mechanics. For some reason they almost always blame a starter. :)

If the solenoid were shot, you get a normal crank after the solenoid engaged the gears on the starter. It takes a while to turn over because the solenoid isn't getting enough juice to get things in place.

My money is on the alternator brushes. If it were the belt, you'd hear it slipping. On most modern cars slippage is hard because they use serpentine belts and not discrete belts for each ancillary function. What type of car are were talking about?

The battery _might_ be bad, but it sounds like it ain't getting charged fully for whatever reason.

If I'm right, I like IPAs and stouts.

P.S. If you own a multimeter, measure the voltage at the battery with the car turned off and then with it turned on and report back.
posted by paanta at 3:38 PM on November 19, 2008

Alternator.
posted by mandal at 3:57 PM on November 19, 2008

Autozone tests batteries for free. Sounds to me like the battery isn't holding a charge overnight in the cold because it's defective; your symptom set replicates my experience. Good luck!
posted by ZakDaddy at 4:22 PM on November 19, 2008

If it were a problem with the alternator, the charge light would be lit.
posted by pompomtom at 4:26 PM on November 19, 2008

I agree with peewinkle and pompomtom. If the alternator were bad eventually the battery would go dead and you couldn't start, warm or cold. It takes much more starter current to turn over the motor when it is cold, so many high resistance issues in the battery cables, connections, or the solenoid will only show up then. I have one tractor that I have to replace the solenoid every couple of years because the contacts get scored with use. I'm not sure about your car, but on lots of older cars a good test is to short the solenoid with a screwdriver, and see if the starter turns normally (be careful, though - make sure you're out of gear, watch out for fans, etc).
posted by rfs at 6:31 PM on November 19, 2008