Battery Cable Size

[Pat M]

Good afternoon all,

During & after my trip to Maine, I notice that my rear positive battery clamp has virberated off (not the first time) I think it has to due to the weight of the wire? I replaced the clamp (had to used the black clamp) that came off in Queensbury, NY. I drove home about 8+ hours drive inspected the cable and the stud separated from the clamp. So I decided to replaced the 2 positive wires with a solid wire just as the negative wire is.
The one piece Negative wire is 4/0 and the positive wires are 4/0 (cut-off switch to first positive battery stud) & the jumper (stud to stud) is 2/0 piece of wire. I figuring that the one piece positive wire should be a 4/0 wire. It's not the voltage capacity (600v) of the wire but most likely the 4/0 wire amp capacity? Do I really need a wire that has a rating of 230 amps? Has anyone run into this problem or had a one piece wire made?

Thanks and as always safe travels,
Pat M

[Mark_K5LXP]

If the only house connections you have are the 10-12ga wires then I would agree, the heavy jumpers are overkill. But the photo shows the terminal fractured from overtightening, not cable strain. You could replace the cables with smaller ones with molded terminals but those can break from overtightening too.

Mark B.
Albuquerque, NM

[RobRoy]

Originally Posted by Pat M

Good afternoon all,

During & after my trip to Maine, I notice that my rear positive battery clamp has virberated off (not the first time) I think it has to due to the weight of the wire? I replaced the clamp (had to used the black clamp) that came off in Queensbury, NY. I drove home about 8+ hours drive inspected the cable and the stud separated from the clamp. So I decided to replaced the 2 positive wires with a solid wire just as the negative wire is.
The one piece Negative wire is 4/0 and the positive wires are 4/0 (cut-off switch to first positive battery stud) & the jumper (stud to stud) is 2/0 piece of wire. I figuring that the one piece positive wire should be a 4/0 wire. It's not the voltage capacity (600v) of the wire but most likely the 4/0 wire amp capacity? Do I really need a wire that has a rating of 230 amps? Has anyone run into this problem or had a one piece wire made?

Thanks and as always safe travels,
Pat M

If flexibility is truly the issue, then perhaps use welding cable.

Automotive battery cables are similar, but welding cables are by far more flexible.


When I first got my coach the first day at home, I addressed the battery storage, mounting and cables, cable ends and cable routing.


This is an area in a coach IMO that is very suspect to serious problems in the coach's that I have seen inside the chassis battery storage area and IMO you were very lucky that cable didn’t short out.

Battery fires are very very hard to put out

The reason I did so on mine was that I had a friend lose a $300k coach and a $150k + stacker trailer and they were lucky to get the race car out of the side of the e-way.

The insurance fire investigators and the FD investigators determined that the origin of the fire wad the chassis battery storage area and it was obvious to me.

I made sure all the cables were routed properly and cable ends are secured properly.

I have all the proper battery cable ends and eyelets in my shop and a small press to install them if needed.

FYI you can carefully bend most cable ends to change the angle as to take some of the load off a cable if necessary.

I check my battery storage area at least 4-6 times a year .....cheap insurance .

Happy Trails

[LETMGROW]

The weight of the cable had nothing to do with the failure. They make replacement cable ends which after cutting the cable insulation back you can attach to the cable and reuse the cable. After the cable is reconnected cover the exposed metal parts with a coat of chassis grease to prevent corrosion.
The cable retaining bolt has to be snug but over tightening isn't necessary.

[Pat M]

Good morning all,

Thanks to all who responded. Attached is a picture of the cables, the 4/0 wire is a welding cable. There is no writing on the 2/0 wire, I'm assuming it is a battery cable? I agreed that the crack clamp is because of overtightening but that's the only way to keep it on. I have owned the RV for 4 years and I would say that the clamp has come off at least 8 times, something is going on? The red clamp was installed before my trip from South Jersey to Maine and it made it west to Queensbury NY before it came off. I replaced it with the black clamp and I drove Queensbury (Southbound I-87 in NY is terrible) to my home and the stud separated from the clamp? The issue has to do with the weight, position or stress that the 4/0 wire puts on that clamp? I am investigating a one piece cable that a little longer and will somehow support the weight of that cable and the others as the enter the battery box with no support.

Thanks and as always safe travels,
Pat M
1999 Monaco Executive

[YC1]

Trying to tighten a battery clamp that is bent cannot happen because the two ends are touching before the clamp becomes tight. They can be straightened but a better solution is to replace them and then NOT over-tighten.

The posts should be shiny and clean anytime you are working on batteries.

One way to straighten those misshapen ends is to remove the clamp and then use a nut and bolt to squeeze them flat against each other. Once the shape is established you can use a flat screwdriver to pry them open just enough to go over the post.

No clamp should ever vibrate off, no matter how large the battery cable.

[RobRoy]

Originally Posted by Pat M

Good morning all,

Thanks to all who responded. Attached is a picture of the cables, the 4/0 wire is a welding cable. There is no writing on the 2/0 wire, I'm assuming it is a battery cable? I agreed that the crack clamp is because of overtightening but that's the only way to keep it on. I have owned the RV for 4 years and I would say that the clamp has come off at least 8 times, something is going on? The red clamp was installed before my trip from South Jersey to Maine and it made it west to Queensbury NY before it came off. I replaced it with the black clamp and I drove Queensbury (Southbound I-87 in NY is terrible) to my home and the stud separated from the clamp? The issue has to do with the weight, position or stress that the 4/0 wire puts on that clamp? I am investigating a one piece cable that a little longer and will somehow support the weight of that cable and the others as the enter the battery box with no support.

Thanks and as always safe travels,
Pat M
1999 Monaco Executive

Welding cable is flexible almost like like rope.

I cant tell from the pic want you have but assume your correct

You say its the vertical stud that is also failing?

If so what about using a new 4/0 cable and just reversing the location of the wires?

Mount that smaller 14g or whatever size that is to the top terminal stud where you have previously mounted the battery cable.... and then use a little bit longer bolt on the 5/16 bolt that goes thu the battery terminal post clamp and then mount the battery cable to it like you did with the 1smaller 4g wire?

I would use a new 4/0 smaller size gage cable the correct length with the proper ends that you can buy at the local parts store.

IMO don't buy the from a mass merchandiser.... buy a brand name like Standard Ignition / Belkin or the likes ( there is some very inferior Chinese junk out there so pay attention ) perhaps use a truck supply or seriously local auto parts store.

Ive never had a battery cable loosen but that said ..... if you deem it necessary? use a 5/16 ny-loc nut on that cable to post bolt.

ps: FYI If you nose around on Google and the likes of you can find some pretty trick battery cable ends and a lot of them are used in the mobil audio world.


Happy Trails

[RobRoy]

Originally Posted by RobRoy

Welding cable is flexible almost like like rope.

I cant tell from the pic what you have but assume your correct

You say its the vertical stud that is also failing?

If so what about using a new 2/0 cable the correct length and just reversing the location of the wires and with a new proper sized cable with the proper ends...walla!

Mount that smaller 14g wire or whatever size that is? to the top terminal stud where you have previously mounted the battery cable.... and then use a little bit longer bolt on the 5/16 bolt that goes thu the battery terminal post clamp and then mount the battery cable to it like you did with the 1smaller 4g wire?

IMO don't buy the cable from a mass merchandiser.... buy a brand name like Standard Ignition / Belkin or the likes ( there is some very inferior Chinese junk out there so pay attention ) perhaps use a truck supply or seriously local auto parts store.

Ive never had a battery cable loosen but that said ..... if you deem it necessary? use a 5/16 ny-loc nut on that cable to post bolt.

I did not catch that cable end itself was split also and as stated earlier by YC1 it appears to have clamped and the bolt stressed from bottoming out when tightening and not getting the proper clamp load on the battery post ( pretty common) and can be addressed as he has described in his above post.

ps: FYI If you nose around on Google and the likes of you can find some pretty trick battery cable ends and a lot of them are used in the mobil audio world.


Happy Trails

Edited

[Neptune66]

Check www.batterycablesusa.com they can build a cable exactly to your need,
and at a reasonable price. the website allows you to customize ends, length and cable size, and they ship quick. Been using them for telecom and my coach and avoiding the car audio shops, etc.

[Pat M]

Hello all,

Thanks to all who responded. I finaling talk to my mechanic and he says he can make what I need. If so great, if not batterycablesusa here I come. After going on their website, Neptune66 you are correct I believe they can make what I need.

Thanks again and as always safe travels,
Pat M
1999 Monaco Executive

[Neptune66]

Originally Posted by Pat M

Hello all,

Thanks to all who responded. I finaling talk to my mechanic and he says he can make what I need. If so great, if not batterycablesusa here I come. After going on their website, Neptune66 you are correct I believe they can make what I need.

Thanks again and as always safe travels,
Pat M
1999 Monaco Executive

You are welcome! Just know that the batterycablesusa has hydraulic crimping for full wire density in the connector. It makes the crimp almost into a solid conductor in cross section for lowest loss/heat.
Good Luck!

[Pat M]

Good day all,

This is the final result. A one piece battery cable made from 4/0 welding wire that is very flexible. Should work fine, test run will be traveling to Florida from New Jersey after Christmas.

Thanks to all who responded and as always safe travels,
Pat M
1999 Monaco Executive