Electrics: 2003 S60 Battery Woes

[mannyo1221]

Last Friday was not a good day.

I started and drove the S60 to work, all was fine.

I returned to the car to drive home at the end of the day, and the car was totally dead. There was no life at all, had to use key to unlock, nothing at all from the instruments or anything electrical.

AA called, they turn up, hooks up car to his van but there was not enough oomph coming from his van battery which was connected with large cables to the jumper points under the bonnet, even with his engine running.

He then goes to hookup a booster pack directly to the battery. We then discover the horror, a massive mushroom sized green glob of corrosion on the positive terminal. He sprayed some acid neutraliser onto the terminals, then cleaned the terminal and hooked up the booster.

Hooray, the car starts and I am on my way. Got home, about 18 miles and switched off, everything goes totally dead again so the battery is dead.

I got a replacement battery from Halfords (only place to get one in a hurry), got the old battery out and set about cleaning as much of the mess as I could.

I am not sure what the OEM positive battery clamp is meant to look like, but I suspect mine has had some of it eaten away by the corrosion. Anyway I cleaned it up and got the new battery hooked up. The clamp looks kind of weird, the side opposite where the cables come in seems to be quiet thin and not what I expected, whereas the side where the cables are is very thick.

At least the S60 is now working again, but what caused this corrosion again. I had it while back, but though I had that sorted then. Could the failing old battery have generated the problem.

[cheshired5]

The most likely explanation is that the battery vent tube wasn't connected or was blocked and the hydrogen gas produced from charging accumulated in the closed area and caused the corrosion.

[Simon Jones]

Normally, you put petroleum jelly (Vaseline) over the terminals and clamps to help prevent oxidisation. While the location of the battery in the boot means its well protected from cold and damp, it also tends to miss out on regular inspection, especially if it's got the plastic cover that was fitted to one of my XC70's.

[Georgeandkira]

There has to be umpteen videos on battery installation and maintenance so please forgive the following....

Baking Soda (sodium bicarbonate) and water and a brush is what to use to clean a battery, its posts, the cables' clamps and often the pocket or tray where the battery mounts.

==>You'd be surprised how much fizz you'll see when you clean the battery's environment.

==>Remember to turn the cables over to see their undersides. You'll find crud there and you must pick or brush it out.

==>While Vaseline, silicone paste or dielectric grease all protect OK I recommend real battery terminal spray. The stuff works well and the treatment lasts for years.
I mask with paper with a hole in it and spray the posts. Then I attach the clamps, mask around the cable and spray the entire clamp. Nothing has ever corroded on any battery since I first saw this stuff at a garage.

[mannyo1221]

And she is all fixed up.

New battery fitted as the old one had failed and it looks like the fumes were escaping on the top of the battery, there appeared once removed and looked at more closely to be a fine mist of something on top of the battery. Cannot confirm what it was, and it's now been taken to the council recycling centre.

Garage has replaced the small cable that runs to the rear electrics module, and also replaced the positive battery terminal on the cable. The old one was completely shot, the acid had been eating away at it for ages.

I'll periodically remove the battery cover and keep an eye on it going forward. The mechanic said it should be ok now, but I've heard that before.

[Simon Jones]

Glad you've got it sorted. There should be a small vent tube that connects to top of battery that takes the excess gas out under the car. Many aftermarket batteries don't have this feature but when the battery is situated under the bonnet it doesn't really matter. However, if you've got a battery in the boot then all the highly explosive gasses that occur during the charging process will be wafting around inside the car.

[mannyo1221]

The replacement Yuasa battery has the vent hole in the same place as OEM. it was securely attached to the old battery, and is now connected to the replacement. From what I can tell the pipe is clear of obstruction.

I hope this is the end of the matter, when I had the corroded terminal just over a year ago I should have checked the battery more thoroughly as it may have avoided the incident occurring again.

[petey]

It’s possible that rather than chemical attack tearing apart the terminals, it could just be that they were loose; loose connections carrying big current, say at cranking, will spark and erode in almost exactly the same way as an arc welder melts metal. Again, because the battery is in the boot, it very rarely gets checked for tight terminals, probably less frequently than it gets checked for corrosion.

Also note that it’s only ever going to be the positive terminal that will corrode, that’s why the car has a negative earth (electrons move from the negative cathode pole to the positive anode pole). Negative earth means that the majority of the vehicle is negatively charged and therefore less prone to electronic corrosion.

[Brendan W]

Originally Posted by mannyo1221

New battery fitted as the old one had failed and it looks like the fumes were escaping on the top of the battery, there appeared once removed and looked at more closely to be a fine mist of something on top of the battery.

Has anyone checked the charging voltage ?
If it is too high it could be boiling the battery and might explain some of the escaping vapours and so forth.
12.6 cold fully charged
13.5 ish at idle
14.4 ish at 2000 rpm and not exceeding this by too much ever
15 is getting into risky territory.
13 ish after shutdown, slowly falling to 12.6 over a few hours.