Battery Cable Connections Vibrating loose

[DayCruiser]

How do you resolve this problem? My ground cable keeps vibrating loose. I got the positive cable to stop doing it ie locking nuts. The ground wire comes loose at the cylinder on the post. So I go out and buy a cable that has less pieces to put together. A $24, 41" cable. Much thicker cable. I swear even that came loose at the post. The Voltage meter showed a little over 14 but that is better than what it did before the fix and the boat ran with more HP--I/O 130 mercruiser). Seems that when the battery doesn't have a solid connection the boat runs slower at the same RPMs than when the battery does have a good connection. Started off correctly but as it vibrated loose the voltage meter went over 14. So then I put a locking nut on that and tighten it to where the ends touch. That is as far as it will tighten. Probably go for a ride today and see if that works

 

[fishrdan]

Re: Battery Cable Connections Vibrating loose

So then I put a locking nut on that and tighten it to where the ends touch. That is as far as it will tighten.

Explain further, not sure what you meant there.

Definitely use nylock nuts on the battery posts and tighten the cables with a wrench/socket, if it won't tighten securely (I think that's what you meant), put a SS washer between the cable and nut. Is the battery securely mounted to the boat with a strap or hold down bracket?

 

[DayCruiser]

Re: Battery Cable Connections Vibrating loose

The new ground line had a snug fit before I started tightening it so it was the correct size. I tightened it to where it was hard to turn but not so as to bend it where the ends of the loop met. Still it vibrated loose. So when I got back and found it loose enough to turn with your hand then I put the lock nut on it and tightened it to where the ends of the loop touched. 1990 boat that I have had for a long time and it didn't come with straps on the battery or a bracket. Tight compartment with little room but that would help some for sure to have it solidly positioned.

 

[fishrdan]

Re: Battery Cable Connections Vibrating loose

It sounds like you are using an automotive style battery cable, (clamps around the side of the post instead of the top of the post), correct? A battery's negative post is smaller than the positive post, so if you have a clamp meant for the positive post, it will be loose on the negative post. In a pinch, I've used a file and took some material off the "gap" of the clamp, so it can tighten around the negative post. But it's best to get the correct cable so it will have the correct diameter hole to fit the negative post.

Look close at this pic and you can see a difference in the hole size of the 2 clamps.

I'm using an automotive battery in my boat and it was a chore finding a high quality (not the cheap lead style) negative clamp,,, locally. Everyone had the positive clamps, but for whatever reason, they didn't carry the negative clamp.

 

[dingbat]

Re: Battery Cable Connections Vibrating loose

How do you resolve this problem?

Use the proper cable connections. Automotive type clamps and wing nuts have no place on a boat.

 

[DayCruiser]

Re: Battery Cable Connections Vibrating loose

It sounds like you are using an automotive style battery cable, (clamps around the side of the post instead of the top of the post), correct? A battery's negative post is smaller than the positive post, so if you have a clamp meant for the positive post, it will be loose on the negative post. In a pinch, I've used a file and took some material off the "gap" of the clamp, so it can tighten around the negative post. But it's best to get the correct cable so it will have the correct diameter hole to fit the negative post.

Look close at this pic and you can see a difference in the hole size of the 2 clamps.

I'm using an automotive battery in my boat and it was a chore finding a high quality (not the cheap lead style) negative clamp,,, locally. Everyone had the positive clamps, but for whatever reason, they didn't carry the negative clamp.

Use the proper cable connections. Automotive type clamps and wing nuts have no place on a boat.

I have always use Marine color coated clamps. Black smaller one for the negative. Still the ground is vibrating loose. So this time I went with the one unit more expensive ground where there is no bolt to connect the line to at the top. Black line for ground. Smaller connection and perfect fit. Still vibrated loose to where I could turn it with my hand. The one unit looks as safe or safer than the Marine type with no areas to spark--to me anyway. So I tightened it down really hard and put a lock nut on it. Hopefully that will do the trick