9456836 Ramac B+ battery cable: early failure due to poor crimp!

[jreed]

This is a follow up post to report on early failure of an aftermarket B+ battery cable I installed on my '97 855 GLT (now at ~170k miles). I bought and installed a Ramac brand positive battery cable a couple of years ago. It worked well for about 1.5 years and then began failing intermittently. The symptom was intermittent No Crank. I discovered the cable had failed by running a voltage drop test from the positive battery terminal to the starter connector while trying to start the car. The voltage drop started out at about 0.5 Volts and as I kept cranking the voltage drop increased to 1.0V over about 10 seconds. Pressing on the main red-insulated wire leading into the positive connector at the battery-end of the cable would reduce the voltage drop and the car would crank again.
Here is a photo of the installation showing the positive terminal. The crimp that failed is hidden underneath red shrink wrap tubing:

Positive connector of Ramac, showing failed crimp still covered up with red shrink wrap tube.

IMG_6769.jpg (67.21 KiB) Viewed 2301 times

My original post about the Ramac cable is here:
https://www.matthewsvolvosite.com/forums ... =1&t=47706

I took the red shrink wrap tube insulation off of the cable. There was a big gap between the crimp and the wire.

Poor crimp connection

Ramac p01.jpg (156.36 KiB) Viewed 2301 times

I cut off the cable and then sliced open the failed crimp with a fine toothed hacksaw. This deep into the crimp, there appears to be a good connection.

After slicing the crimp open

Ramac p02.jpg (249.57 KiB) Viewed 2301 times

At the end, there was a large gap all the way around the wire that extended deep into the crimp connector.

View of large gap between connector and the wire

Ramac p03.jpg (157.04 KiB) Viewed 2301 times

I looked inside the crimp and could see all the way down to the point I had sliced in one area.

Showing the length of the connector that was poorly crimped.

Ramac p04.jpg (220.91 KiB) Viewed 2301 times

I cleaned up the end of the copper cable and installed a little bolt-on battery terminal. It seems to be working OK for now.

New bolt-on terminal

Ramac p05.jpg (235.63 KiB) Viewed 2301 times

[MrPc]

Wow. What is it with the crimps on these battery cables?

Last November I posted a description of how I soldered the failing crimp on my factory cable.

https://www.matthewsvolvosite.com/forums ... =1&t=60223

I bet the failure mode is the same--voids in the crimped part of the terminal--and the same fix might have worked here too. Mine really absorbed a lot of solder, which speaks to the size of the voids.

Mine has been working fine ever since, but it has only been about two months...

[BEJinFbk]

I don't think the crimp failed so much as the cable.
There's a bit of green in the pic indicating corrosion.
I have a feeling that the crimp wasn't made correctly
and moisture based corrosion degraded the copper strands.

Looking at what you posted, that clamp looks like a
pretty stout part. I'd bet that if you had an uncrimped
one in your hand, you'd see stepped barrel diameters.
Smaller at the top, where the crimp looks good and a
larger diameter towards the opening of the barrel.

If I'm right, that long barrel was designed to crimp copper
at the top and copper WITH it's insulation at the mouth.

I'm thinking that who ever built that cable stripped too
much jacket. Without the insulation being crimped in the
lower half of the crimp barrel, you didn't get a good moisture
seal or the strain relief that the connector was meant to provide.

It also looks like the heat shrink that they used didn't have any
hot melt inner lining to seal the poor crimp. The wrong heat
shrink can actually allow moisture to infiltrate and then trap it.

I suspect that you bought a Good Connector, but a Poor Assembly...

[bob850]

I recently had the RAMAC cable fail on one of our 850 wagons. I ended up reconnecting the original factory cable after rehabbing it a bit. Working fine for now.

[jreed]

That's good to know! Thanks. I ended up building a new cable, in part for the experience of getting to do some soldering and heat shrinking, and in part so I could increase the gauge of the cables.
I wrote up a little DIY guide to cable making, with parts list, here:
https://www.matthewsvolvosite.com/forums ... le=desktop