Fixed the battery problem. New problem?

Okay, long story. A friend gave me a 1989 Honda Prelude that had been sitting out for a few months. Over the next year, I had to jump it whenever I needed to use it (on average once a week). Took it to a shop 3 times, had the system checked somewhere else, and had my electrician father look at it. Everything always looked fine, tests came back clear. Eventually, we discovered that the fan was kicking on long after the car was off and draining the battery. Broken fan control module. Took it to the local dealer, had it replaced. Everything ran great for a while. It started up every day just fine.

Then it snowed. Now I have to jump it almost every morning, but it’s fine when I leave work. Sometimes it needs an afternoon jump when it hasn’t run in a couple days. I know that a first, big snow can shock and ruin a cheap battery like mine. That’s gotta be it, right? Ran fine for months, then it snowed, now it needs jumping.

Let us know how you came upon your info about “how snow shock can ruin a cheap battery” as I don’t know this to be true.

What can ruin some batteries is even one deep discharge.

I read it on several online forums. I don’t know much about cars (can you tell?) but that’s something that plenty of people said.

A fully charged battery will hold up just fine in cold weather. Now a discharged battery will freeze when the temp drops and when it freezes it is junk.

I’m not sure if it was discharged or not. I guess what I’m asking is, if everything is running fine, can sitting under snow for two or three days kill a cheap battery in a 20 year-old car?

If the charging system is working correctly and the battery is good sitting under snow for two days should have no affect at all.

How far do you drive this car every day? If it’s only a few miles it might not be enough to keep the battery charged.

Has the charging system been tested? Has the battery been “load tested.?”

I drive about ten miles to work (mostly highway). Takes about 15 minutes. It ran perfectly for 3 months until one day it snowed. When I tried it 2 or 3 days later it was dead. Two mechanics and an auto parts store all ran the systems check and/or inspected it and everything looked okay.

I haven’t tested anything since the original problem was fixed in November. But they specifically tested the alternator etc. and it was okay.

Two things immediately come to mind. Cold can affect both the battery and electrical parts/connections.

Battery efficiency is affected by cold temperatures. If the battery has been compromised enough, a cold snap can be the straw that breaks the Camel’s back so to speak. Your battery has been subjected to a number of deep discharges and those are most certainly detrimental to the battery’s capacity to hold a charge. Couple that with a cold snap and you can have a battery that can’t meet the significant demands of starting the engine.

Electrical parts and connections are affected by temperature just like any material; they expand and shrink as the temp rises and falls. A marginal part or connection can open or short out depending on ambient temperature. You had one component fail and turn on the fan when it wasn’t supposed to. Perhaps you have something else acting up now- or even the same part, and draining your battery when you’re not looking.

You can have the battery load tested as a means of establishing its ability to deliver large amounts of current. However, these tests are not always definitive. As an example, you could have warped plate(s) in the battery that onyl act up when the conditions are right. If it fails the test, it’s definitive. If not, don’t rule it out. Based on what you said your battery went through, I’d replace it. Cheap insurance. Most auto stores will do this test. They can also check the alternator output at the same time to verify it is properly recharging the battery.

If you still have the problem, I’d start searching for other culprits like parasitic drains or nightime gremlins like the previous problem.