Battery: Tightening positive cable

The new batt positive is prob a bit more cone shaped (Kirkland).
After coming home, when I tried to check the tightness, it just came off.
Believe the terminal being cone shaped is making it to slip upwards easily.

I tightened it but now I am scared to check the tightness!
If the connection becomes loose due to driving, the batt won’t get charged properly and may die soon.

What is the best way to take care of this situation?

A common mistake that is made when tightening the battery clamps is they get over tightened from the belief that will make a better connection. That stretches the connector out and can cause it to become loose after time. By cleaning the connections with a battery post cleaning brush and tightening the clamps just enough so they don’t slip to the side will make a good connection. A sealer should be then sprayed on the connection to keep corrosion from forming on the connection. If the clamp is too loose you could perhaps pound out a small lead fishing weight to a thin strip and wrap a single wrap around the battery post to expand it slightly and fit the clamp.

If there was still a gap on the open end of the connector before you tightened it, you are probably fine.

If the connector is stretched to the point that the gap at the end is touching, it is best to just replace the connector. They are usually less than $3-$5 at any auto parts stores, and you only need basic tools to do the job (wrench, wire cutter, knife). As always clean everything well and apply your favorite anti-corrosion chemicals, I like metal-based anti-seize compounds.

I’ve snugged up a loose connector by slipping a bit of thin tin/lead solder in there.

The post might be tapered but the connector is tapered too, so just tighten it up so that it won’t move or rotate. You shouldn’t be able to pull it off but if you can’t get it tight then get a replacement connector as discussed.

Check the tightness. If it is not tight, then it is possible that the cable terminal has a hairline crack in it or the bolt and nut have so much corrosion that it wont tighten up. I always open up the clamp as wide as possible, then push it down as far as possible over the battery post so that some of the post is proud of the cable, about an 1/8" or so, then tighten the clamp down good and snug. Then I test it for tightness. I do not seal it.

I am going to rewrite this post. As I think about it, the most common reason I see for a loose battery cable, either + or - or both is that the person who did the install did not spread the clamp out before installing the cable. Therefore, when they put the clamp on the new battery, it does not go down on the post far enough. If you don’t have at least 1/8" or post above the clamp, then you need to redo the cables, open the clamps up enough to get them down on the posts.

One more thing, if you really torque down on the battery cable nut, you can crack the post inside the battery and that wont be good. It should hold with just a good snug.