Battery Connections

[namba209 (R.I.P.)]

You folks all know how we keep pinging on keeping all the electrical connections clean and tight. Had a strange thing occur to my neighbor yesterday, so I thought I would relay what happened here, because it is indicative of what we strongly maintain about the connections. As I went out to the garage to put out a nicotene lo-level lite, I noticed the neighbor had his hood up. So being the curious person I am and being a tad mechanically inclined, I strolled over to see what was up. He said the car wouldn't start, he figured the starter or solenoid was flakey. I asked him to try to start it and there was nothing, no click of the solenoid, nothing. So I got my battery and took it to his car, hooked up the jumper cables and it lit rght off. I went and got my VOM to check out his charging system and noted something very strange. Measuring the voltage on the battery posts, I got 12.87 volts, measuring the terminal clamps to the posts I got 14.29 volts. A 1.5 volt difference, approximately, both measurements taken at engine idle RPM and the probes of my VOM were moved about 1/4" from the posts to the terminals. We cleaned both the posts and inside the terminal clamps and did the measuring again, this time both measurements were the same, right at 14.3 V. Now to emphasize, both battery conections were tight, we needed a wrench to remove them, but a layer of corrosion was evident after they were cleaned with a battery terminal brush. So, even though the connections are tight, you still may not have a good conection. Just a heads up for you all out there.

[jeff denton]

I was asked to take a look at the school van yesterday, they thought the starter was bad. Well, ya start at the battery, ya know. Took a look, all right. Saw those crappy K-Mart battery post terminals, you know the kind that you bare the cable and pinch it into the terminal with two bolts and a bar. That is a no no. Temporary fix only! I cut them off and soldered some proper ring terminals on and hooked them to the side post terminals. Fixed.
Tip: when using side terminals, don't just use a bolt. Use a bolt with a nut on it so you can bottom out the bolt in the battery, then tighten the terminal to the battery with the nut. This leaves the bolt head sticking out so you can easily attach a jumper cable if you have to.

[GTJIM]

Some good points! A light smear of chassis grease on the terminals helps slow down corrosion and oxidation of the terminals - but don't use "Moly" grease as it has a much higher resistance. There are also proprietary substances to smear on the posts before installing the clamps - but I have found the clear, gold/yellow coloured Multi-purpose grease will do the job just as well.
There are also grease impregnated felt washers available that go on the terminals underneath the clamps - they often have basic chemicals in them that neutralise any spilt acid or acid fumes in the area....
Amps must get through with out too many Volts being lost!!

[namba209 (R.I.P.)]

Now that's a neat idea Jeff, I went looking at the monza battery connections after reading your thread and found the cable ends with the side mounting plates had a very thick coating of corrosion on them. Figuring that was one of my problems with it, I attacked them with a brush and didn't even scratch the surface of them, and dropped one of the bolts in the process. Thinking I would have to get another one, I couldn't find the one I dropped, I checked the threads out on one off Willit? and found they are 3/8-16 thread. So the next time I'm out and about, I'll pick up a couple of 1.5" long 3/8-16 bolts and a couple of nuts for Willit? The battery in the monza has both side and top mount connections so I'm good as far as being able to get a set of jumpers on it if needed. Oops, forget that, I got a pair of top to side mount adapters for Willit? when I got all the battery stuff for it. But it's still a great idea.

[baz]

there is 1 quick cleaning fix that i have found thats good for the white acid corrosion ,
stick the clamp into a cup of boiling water ,the deposits dissolve off and leave a nice clean terminal ,then rub a little petrolium jelly(dont know what its called in the states) on it and refit

[hrcollinsjr]

petrolium jelly(dont know what its called in the states)

Uh, petroleum jelly.
It's called Vaseline (brand name) by many.

Harold

[yellaopelgt]

Sounds odd but I'll say it anyway. My Grandfather used to smear petroleum jelly on top of the battery(small area) and stick a copper penny in it. The corrosion would adhear to the penny and not to the terminals!!! Sounds crazy, but it does work!!!
Joe

[bq97]

There are two issues with using either automotive grease or petroleum jelly on battery terminals. One is they are both dielectrics, which means they are poor conductors of electricity. This can easily be demonstrated with a quality digital multimeter set to measure resistance, taking the leads and sticking them in a tub of grease or petroleum jelly and recording the reading. Now stick the leads in a glass of water or touch them to your finger and see the difference in resistance.

The dielectric grease, also sold as “Tune Up Grease”, that is typically used inside spark plug boots keeps out water and creates a barrier so the spark cannot find a lower resistance path to ground without going through the spark plug.

The other issue is both automotive grease or petroleum jelly are flammable where as “Tune Up Grease” is not.

Battery corrosion is formed when the small amount of hydrogen gas is released from the battery during normal operation combine with other agents typically found around a battery and attacks the softer metals, i.e. lead and copper. Coating the terminals in any persistent substance forms a barrier that the hydrogen gas cannot penetrate, therefore no corrosion. If the barrier is broken corrosion will form underneath it.

The best method for keeping the terminals free of corrosion is to keep them tight and free of foreign materials since the hydrogen gas alone will not start the corrosion process.

Often dirt will get between a loose connector and the battery terminal where combined with hydrogen gas from the battery will start the corrosion process. The corrosion will in effect tighten the connection as it grows outward creating a dielectric barrier between the battery post and the connector resulting in poor current flow to and from the battery, excess heat, and if sever enough create a leak down circuit and discharge the battery over time.

Electronics 101

Brian

[wrangler]

Was just about to talk about dielectric grease when I went back to re-read the thread and saw that you had just mentioned it. I not only reccommend this for the battery terminals, but also for the ground. I recently had a problem that I eventually traced to the ground straps. I thought the starter had gone bad on me when it eventually came down to poor ground connections. The dielectric grease will prevent this from happening again, so, if you replace or reconnect your grounds, save some hassle down the road and add a little at the same time... " a lil dab will do you"

[jeff denton]

I should have mentioned. Long ago I was taught to use "anti-seize" on the terminals, I have ever since and it works great. I use it on wires after stripping them and before sliding them into crimp connectors. Keeps them from turning green, a huge problem on trucks here since they started salting our roads a few years ago. It wasn't a problem before that... It is hard to keep truck and trailer tail lights working anymore unless you are just anal about how you install and wire them.

[namba209 (R.I.P.)]

Jeff, the reason the anti-size compound works so well is because it is graphite based. You know, the stuff the new wire less spark plug cables are made of. I've used the stuff I got from the USAF for years, I just coat the first 3-4 threads on all my bolts and as it's screwed in it coats the rest of the threads. It is used exclusively on igniter plugs on air cooled aircraft engines. If it is not used, the steel plugs will gall and strip out of the aluminum heads. It makes a really good path for grounding the plugs to the heads. Hmm, now I gotta think about coating my battery terminals with it, but it is really icky stuff to get on you.

[jvandyke]

Get in car yesterday, hit start, everything dies. Suspected battery terminal connection despite having replaced/cleaned tightened everything last year. Sure enough, bang on the hot side, started up.
It was so tight I couldn't remove it, it fell apart on me. I think the weak link was the clamp on the cable. Off to replace with something better, no side terminals on this battery that I can see, let alone get at. Anti-seize at the ready!

[jvandyke]

Rebuilt hot terminal with same as before but one made for the larger gauge wire so fits better. Cleaned and coated with anti-seize. Hopefully it's happy for the season now. Maybe this is somehow related to my fuse blowing on my electric fuel pump circuit? Maybe even responsible for dim lights? Have since upgraded the alternator anyway.