Another problem with electrical.

[IronMonkeyL255]

For some reason, the last few days, my car hasn't wanted to start like normal.

Thursday I mentioned that it wasn't starting, so I ripped out the security system just to find out that I needed a jump.

Friday it seemed to be just fine.

Saturday, it was fine until after the Subaru Challenge. It took a little bit, but was still able to start under its own power.

This morning, It was fine when I started it up at 6:00, but I needed a jump by the time I got out at 10:00. That's 4 HOURS!

What could be causing these problems all of a sudden.

Advance Auto checked my alternator and battery, and they both seem to be fine.

[dzx]

I dunno how far i would trust advance when checking a battery, your battery was probaby deep drawed too many times and wont hold a charge now.

[IronMonkeyL255]

I went to go start it up tonight, and it had trouble again. I didn't need a jump, but it took a bit to get it going.

Any good way to check my battery on my own?

[vrg3]

How old is the battery? I don't know a good way to really test a battery yourself, but if it's old and seems to be not holding a charge, I'd just replace it. You can get an economy battery for as little as $30.

Or you could try taking the battery to another AutoZone and see what they can find. I've had bad luck having AutoZone test my charging systems... the guys don't know what they're doing and seem to get upset when I point out their mistakes. No matter how sophisticated the testing machine is, it won't work right if it's not being operated correctly.

[IronMonkeyL255]

It's only about a year old.

I believe Opie put it in when he first bought the car.

I'll try taking it to another place or two to see if they notice anything different.

[vrg3]

Are the cables in good shape? Next time it happens, try putting a quality jumper cable from the battery's negative terminal to the hoisting ring attached to the alternator. The positive cable is harder to safely attach with a jumper, since it would have to go to the ring terminal on the starter, but you can at least test the negative one this way.

And of course first check that the connections are tight. Don't overtighten the battery terminals, though; the posts are made of soft lead that can and will deform permanently.

[magicmike]

yeah, what vrg3 said. Sounds like your terminals are dirty. If they (autozone) checked your batery with a multy meter with the bat in the car then they probably just touched the posts and not checked at the terminals. You can usualy see a voltage drop from the terminal to the post if they are indeed dirty.

Oh yeah, get some of those red and green felt discs that go under the terminals to prevent oxidation.

[IronMonkeyL255]

The connections seem to be in good shape. There isn't any excessive corrosion on them.

I have been careful not to overtighten the clamps, as I remember someone mentioning that they had to get a new battery because they over-tightened the clamps.......

Could it be a short somewhere causing the battery to drain? If it was constantly having this problem, that would make sense. Since it isn't (sat overnight and fine, but sat for 4 hours and went dead), I don't fully think that is it.

When I removed the security system, I checked what under-dash electronics I could get to. They appeared to be fine.

[vrg3]

Yes, it could be excessive parasitic draw.

You could try measuring the current flowing through the battery when the car's turned off. The simplest way is to disconnect the negative terminal and stick an ammeter in between the terminal and the post.

You shouldn't see more than maybe 40 or 50 milliamps. If something's very wrong, though, you could see a lot more, so you should make sure you're using a meter that either has a large range or is well protected from overcurrent.

If you don't have an appropriate ammeter, you could put something of small known resistance (like a small piece of stainless) in between the terminal and post, and then measure the voltage across it. That voltage in volts divided by the resistance in ohms is the current in amps.

Is there any corrosion at all on the terminals? If there is, you should clean it off. A mixture of baking soda and water helps, but be sure to rinse it all off. Then put the felt washers on like magicmike said, and rub dielectric grease all over the posts and terminals both before and after connecting them.

[IronMonkeyL255]

grr.....

I can't seem to find my dad's new multimeter.

Looks like I'll have to go get my own.

I cleaned off the posts and clamps and di-electric greased them and it started up fine.

[magicmike]

If you don't have an appropriate ammeter, you could put something of small known resistance (like a small piece of stainless) in between the terminal and post, and then measure the voltage across it. That voltage in volts divided by the resistance in ohms is the current in amps.

Damn vrg3 you are one smart mofo. Got to give you props once again.

[IronMonkeyL255]

I've said it before, and I'll say it again: vrg3, you are a genius.

[IronMonkeyL255]

Hmm.....

It looks like corrosion on the terminals may have been one of the main problems.

It started up fine going to work yesterday, when I got out of work, and it started fine this morning.

[vrg3]

Well, the stainless trick is pretty standard, really. It's commonly used by mechanics as it's one way to make sure you don't blow up your meter.

That's cool that it was probably as simple as corrosion.

[professor]

I think the real problem here is that the battery terminals are pieces of crap !!!! Sheet metal doesn't cut it.

When I first got my car I had the exact same problem. The negative battery clamp was stretched due it it being crap, and I pulled it right off with my bare hands.

I cleaned it up, and fixed it by using an oversize nut to make it clamp harder.

Seems to me it would be a good investment to install some real clamps, but I haven't done it yet.