How can I keep my car battery from dying in the rain?
February 22, 2005 1:18 PM   Subscribe

How can I keep my car battery from dying in the rain?

I have a 1997 Nissan Altima with a 6 month old battery that runs great, but I left it in Los Angeles in the rain over winter break and the battery died. After jumping it a few times and driving it around for a while when the rain stopped, it would start again in the morning. But the rain is back, and now my car battery (which was working fine when it was dry) is completely dead again after one night in the rain. What is going on here? Some sort of short maybe? The fuse box? It is not due to lights being left on, and it cooresponds with the rainfall. Please help...
posted by rooftop secrets to Travel & Transportation (16 answers total)
Most car batteries have a manufacture warranty on them; you may not even need your receipt. Most car battery will have its own manufacture sticker on it that records it purchase date. Being only 6 moths old feel you have a great chance here for a free replacement.

Do you recall where you bought it? Take it back to the store and hopefully they will replace it with no cost to you. I've done this many times and broke no rules doing it.

As it sounds your car battery is holding a weak charge from sitting too long w/o a charge in it. This problem would show up in moist or cold weather.
posted by thomcatspike at 1:29 PM on February 22, 2005

Also, do you have corrosion around your battery terminals and cables. If so clean them with an old tooth brush as the corrosion will drain a battery.
posted by thomcatspike at 1:37 PM on February 22, 2005

Is it possible that the humidity is exascerbating a problem with corrosion on the battery terminals? Corrosion can cause a bad connection at the terminals that would make the battery appear to be dead. Look for bluish white gunk forming around the terminals, if it's there clean it out thoroughly.

On preview: Yeah.
posted by knave at 1:38 PM on February 22, 2005

i second tomcaspike's (on preview: and knave's) comment about corrosion. this happened to me frequently in the rain in my 94 Accord until i cleaned the terminals (with a battery terminal cleaner brush from walmart) and tightened the connection.
posted by slhack3r at 1:39 PM on February 22, 2005

Yes it could be corrosion, but it could also be your alternator. Or more specifically the belts that drive the alternator, when it gets wet they are more likely to slip and fail to power the alternator fully, thus not charging the battery. Have the belts replaced/tightened.
posted by dirtylittlemonkey at 1:46 PM on February 22, 2005

You would probably hear this as a very loud squealing, however.
posted by knave at 2:08 PM on February 22, 2005

It sounds like the battery needed to be recharged after the first rain incident. Which to me would indicate a short (and a perfectly functional alternator).
posted by squidlarkin at 2:20 PM on February 22, 2005

Yeah, the battery did charge during that time between the rains (albeit slowly), so I kind of figured it wasn't the alternator at that point (no loud squealing either). Corrosion is definitely a possibility though, I did see some of that and didn't realize that could cause this problem. So what exactly is the best tool to do this, and do I need to take the round metal things off the battery in order to clean it?
posted by rooftop secrets at 2:42 PM on February 22, 2005

Thank you everyone! I am going to try this as soon as this godforsaken storm goes away. If you don't hear from me again, it either worked or I was electrocuted while foolishly trying to clean my battery...
posted by rooftop secrets at 3:16 PM on February 22, 2005

Since the question has already been answered...

Don't let it read any Hemingway!
posted by idontlikewords at 3:25 PM on February 22, 2005

Well, I'm no expert, but I don't think problems due to corrosion would go away with dry weather. If you jumped it, drove around, and started it again it's probably not the alternator. A weak charge wouldn't let you start it the second time, either.

I'm guessing a bad ground that moisture is exacerbating. That would explain the moisture dependency and the slow-but-not-defunct charging capability.
posted by RikiTikiTavi at 4:02 PM on February 22, 2005

Adding to the solution, use some dielectric grease after you have cleaned the terminals and cable connections - it'll prevent future corrosion and keep moisture out.
posted by squeak at 5:33 PM on February 22, 2005

Worn spark plug and alternator wires can also do this. Easily replaced, but don't mix them up!
posted by LarryC at 5:47 PM on February 22, 2005

If you don't have any dielectric grease hanging around you can also coat your battery terminals and ends with petroleum jelly.

Also in my opinion a starting battery that has been pulled below 10V (IE: killed dead), especially more than once or for a prolonged period, isn't worth spit. The plates sulfate and develop micro cracks that drive up internal resistance and prevent full charging. If you depend on this car at all I'd replace it at my first chance with a new one.
posted by Mitheral at 1:20 PM on February 23, 2005

"it" being the battery.
posted by Mitheral at 11:46 AM on February 28, 2005

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