Battery Corrosion

Hi.

Got a 95 Suburban K1500 with 180,000 miles. Twice in the last six months, I've had it fail to start with what seemed to be a dead battery. In both cases the positive battery terminal and cable ends were badly corroded. In the first case, the corrosion in the battery terminal was so bad it barely had any threads and I had to replace the battery. Now it's happening again.

In the meantime, I have also replaced the alternator when suddenly it began making a fair amount of noise and not producing enough volts (at least on my in-dash voltmeter).

Since then, the voltmeter, which was former almost always straight up at 14VDC, has been indicating just a notch above the lower red limit, occasionally rising up to the 14VDC graduation.

Seems like something else is going on. First off, I don't understand why I'm getting terminal corrosion with a sealed battery. One guy told me sealed batteries vent off some gases anyway. There's a thread in this forum in which someone said some batteries corrode from the inside down the positive terminal. Neither is a good thing, and I don't recall any of this with the OEM battery or any other battery until the last two.

Could the voltage regulator be the culprit? Is the battery being overcharged and therefore gassing excessively? If so, why does my voltmeter never show over 14VDC and rarely get even that high?

Thanks for your ideas.

PL
Ohio

Hello, I'm assuming that you have the side mount battery cables like I used to. They are notorious for this even with a sealed battery. I would have to clean mine every month and a half or so. It got old quick so I changed my cables and battery to a top mount and it was about six months before I had to clean only a slight amount of corrosion off. One other thing that may be a problem is that you may have corrosion inside your cables. You won't be abel to see it unless you cut and peel back the rubber coating about an inch or more. On my other truck that happened and it went almost all the way to my starter. That will definately have an effect on your voltage gage. Good luck!!

Hello, I'm assuming that you have the side mount battery cables like I used to. They are notorious for this even with a sealed battery. I would have to clean mine every month and a half or so. It got old quick so I changed my cables and battery to a top mount and it was about six months before I had to clean only a slight amount of corrosion off. One other thing that may be a problem is that you may have corrosion inside your cables. You won't be abel to see it unless you cut and peel back the rubber coating about an inch or more. On my other truck that happened and it went almost all the way to my starter. That will definately have an effect on your voltage gage. Good luck!!

Sounds like good advice. Replacing the battery cables is a sensible next step.

Thanks!

I just put felt tabs on mine, u get them at Autzone for like 6 bucks...didnt have a problem... I did have a problem with charging though, I had corrosion at the alternator where the battery lead wire connects to it, a quick touch with a some rough sandpaper, and I was back to 14volts. But since I have put the felt pads on...I havent had a problem at the battery.

I just put felt tabs on mine, u get them at Autzone for like 6 bucks...didnt have a problem... I did have a problem with charging though, I had corrosion at the alternator where the battery lead wire connects to it, a quick touch with a some rough sandpaper, and I was back to 14volts. But since I have put the felt pads on...I havent had a problem at the battery.

Sounds like a much easier first step rather than replacing the battery cables. Would use an electrical contract grease accomplish the same thing?

Sounds like good advice. Replacing the battery cables is a sensible next step.

Thanks!

I had given the battery ends of the battery cables a real good cleaning and applied electrical contact grease (clear). Still can't keep the volts up, and now when I first start the truck it occasionally lugs down and stalls, preceeded by the voltmeter going into the low red zone.

I had a kid at the battery store test run their test on the battery and he said it was great (and he's motivated to sell a new battery). His diagnosis was that the alternator is bad.

So I finally got the truck into the Chevy dealer to try to figure out what's going on. They said the battery is good, and they say the alternator is good too (it's under their warranty, so they're motivated to NOT have an alternator problem). I asked what they thought about the battery cables, and they said they looked ok.

Their diagnosis was that the voltmeter was bad, and that a replacement instrument cluster would be $500. I asked how a bad voltmeter could relate to the stalling, and they had no opinion.

So the battery stays charged, the starter spins at full speed, and everything seems okay except: a) the voltmeter reads low; b) it stalls sometime when starting (preceded by voltage dropping); and, c) there is more corrosion on the positive terminals of the battery than I think should be there (and which hopefully the grease will stop).

Everyone I talk to outside this Chevy dealer says it sounds like the voltage regulator, which is integrated in the alternator housing.

I know you guys have said to change the battery cables. If the cables have internal corrosion and intemittent connections, I guess I could see all this stuff happening. Still sound like the right move?

Thanks
PL

Just picked the Suburban up from the dealer. Here's exactly what the worksheet says:

"Checked charging system and say output of 60amps @ 13.24 volts (40amps @ 12.28 volts with the a/c running). The [voltage] gauge is reading incorrectly. Customer declined instrument cluster replacement of $487.50"

No kidding I declined. These voltages seem low, and the gauge is definitely reading lower that it did before the battery/alternator/starter replacements in the last year.

I'm going to have an auto electrical shop look at it. I expect they'll say the alternator needs to be replaced, and I have to go back and argue with the dealer to do it under warranty.

Do you know if the alternator output stated was done with a load placed on the battery and the engine reved up a little?Is this the actual output at the alternator or what is getting to the battery?If 60 amps is what is going to the battery,then the battery needs to be charged.If 60 amps is what is coming out of the alternator with a load put on the battery,I would say that the alternator is not putting out its maximum output and should be replaced.If my memory is functioning properly,the alternator on your vehicle should put out approximately 100 amps maximum.Check with your dealer or local parts store.Have you gotten a starter draw test done to eliminate the starter as a problem ?Check all the cable connections.Not just at the battery.You could have a bad ground connection from the engine to frame or at the themostate housing.I believe there is a main ground at the thermostate mounting bolt.I hope this can help you solve your problem.
chuck's

Do you know if the alternator output stated was done with a load placed on the battery and the engine reved up a little?Is this the actual output at the alternator or what is getting to the battery?If 60 amps is what is going to the battery,then the battery needs to be charged.If 60 amps is what is coming out of the alternator with a load put on the battery,I would say that the alternator is not putting out its maximum output and should be replaced.If my memory is functioning properly,the alternator on your vehicle should put out approximately 100 amps maximum.Check with your dealer or local parts store.Have you gotten a starter draw test done to eliminate the starter as a problem ?Check all the cable connections.Not just at the battery.You could have a bad ground connection from the engine to frame or at the themostate housing.I believe there is a main ground at the thermostate mounting bolt.I hope this can help you solve your problem.
chuck's

Thanks for the quick response. I don't know any of the details of how the testing was done, but I'm taking the truck to an auto electrical system specialty shop tomorrow to see what they think. I did meter the battery with the engine off last night, and it was a little above 12VDC. Even when the truck wouldn't start and everything seemed dead, the battery was fully charged but the + terminal was badly corroded (green/hard stuff, not fuzz). The symptoms would point to overcharging, not undercharging, but the voltmeter never gets to 14VDC, which is where it normally sat for the past 10 years and 150,000 miles I've owned the truck.

I'll post what the electrical shop finds.

PL

The electrical system specialist said the problem is the battery cables. It was a poor design in his opinion, and he's replaced the cables on his own Chevy truck.

He says the battery and alternator are okay, and that the voltmeter in the dash matches what he reads with his voltmeter. Best of all, he said don't spend any money with him, the cleaning and the grease should keep things okay.

So, I'm about 500 miles into a 1500 mile trip and everything is fine. So I'll just check the cable ends on occasion and see how it goes.

I'm assuming the corrosion problem you are having is on the ends where they attach to the battery. The best way I have found to clean them is remove them from the battery and put them in a cup of water with baking soda and leave them for about 30 min. The corrosion builds up inside the plastic insulating caps the are molded onto the cables where you can't see it. The soda/water solution works better than anything I've found and I've owned a lot of GM vehicles. Make sure to rinse them good with clear water and apply grease before putting them back on. Good luck. :)

I just had a problem with mine. I have 2 cables from the Positive terminal. One goes to the starter and one to the electronics juction box on the drivers side of the hood. Noticed a bit of corrosion on the cable going to the electronics box. I was going to cut the cable back and replace the end witha after market side terminal. Well the corrosion was over a foot back. Went to the dealer and bought the factory cable. Works great $50 bucks later..

Yeah the duel wire design that GM uses on it cars is horrible when it comes to corrosion, the corrosion also leads to resistance and that could be a contributing factor to your power problems. Before I cleaned my terminals my voltometer always read at the lower spectrum of the 13.6-14.6 of the normal battery operating specs. Once I cleaned them with good old fashion baking soda the voltometer read a steady 14-14.3. I've even used the grease method to prevent the corrosion to no avail. Also the standard AC Delco/Any aftermarket alternator made for GM pickups is supposed to be 100 charging amps. On that statement you got from the dealer it said that it was running a 12.28 volts? You'd be lucky to start a car that had a battery at 12.28 volts, the usualy minimum starting voltage is 12.58-12.6. It definitely sound like the dealer is trying to give you the run around. I've encountered that at almost every dealer I've brought my 95 suburban to.

Yeah the duel wire design that GM uses on it cars is horrible when it comes to corrosion

Thanks for the reply.

Do you know of a good aftermarket cable kit that replaces the GM cable set with something more sensible?