Why does nobody talk about how much torque specs matter on battery terminals?

Had a chat with an old A&P last week who said he sees more electrical fires from loose battery terminals than anything else, and it hit different because I always just snugged them by feel. Has anyone else found a brand of terminal clamps that actually hold torque better than the cheap ones?

3 comments

3 Comments

adamgreen18d ago

...and that old A&P was probably right, idk. I actually read something from a guy who used to work on race cars, and he was saying how even a couple foot-pounds off on a terminal can cause enough resistance to heat things up and start a slow melt. For the clamps, I've had pretty good luck with the ones that have a little set screw or a lock nut on the side, not just the single pinch bolt. The cheap stamped ones feel like they always loosen up after a few weeks in my experience.

riley_taylor18d ago

I read a post from a marine electrician who said the difference between a good and bad connection on a battery terminal can be as little as 0.0002 ohms of resistance, which is basically nothing to a multimeter but enough to start heat buildup over time. He swore by using a torque wrench set to the manufacturer spec, like 60-80 in-lbs for most car terminals, because guessing always led to loose or overtightened connections. The lock nut style clamps seem like a solid workaround though, since they keep the tension even if the bolt backs off a hair from vibration.

kim69317d ago

Man that old A&P knew what he was talking about for sure. My buddy had a truck that kept dying on him, turned out the terminal was just a hair loose and it was arcing inside the connector - melted the plastic right around the post. For clamps, the lock nut style ones from companies like Deka or even the marine grade ones with the stainless set screw have held up way better for me than the cheap stamped autozone ones that feel like theyre made of foil. The difference is night and day if you torque em to spec too, not just tight by hand.