The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Bob_Roller on September 30, 2012, 12:38:57 PM
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I've got a bit of a strange thing happening on my '81 R65 .
I replaced the OEM negative cable, installed a pre-made cable from a chain type auto parts store .
I have corrosion starting on this cable, only on the battery side terminal end .
It's kind of a 'hard' corrosion white in color, needs to be removed with a scotch brite type material .
At first I thought maybe it was dissimiliar metal corrosion, as I had large area aluminum washers to get good contact area, as the replacement cable has a large hole in the cable end, about three times the size that is needed for a motorcycle battery application .
I replaced the aluminum washers with stainless steel and the corrosion still occurs .
I'm going to take it apart and apply some dielectric grease to the cable ends and see if this helps .
I've got a sealed AGM battery, not a 'flooded' type .
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I've always thought terminal corrosion was due to acid fumes venting from where the terminal post pierces through the battery top. I guess AGM batteries can vent too if they are not absolutely gas tight. I just use Vaseline on my terminals. Anything which keeps air from the metal surface would work, even ordinary grease if that's all you had to hand.
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Maybe it had already begun corroding from the inside of the cable as it was likely laying on the docks alongside the Yangtze for a while.
Does keeping these batteries on "tenders" have any corrosion implications?
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Bob, I made a new negative battery cable for my '81 using solid copper terminals, with correct sized bolt holes, sourced from the electrical supply section at... wait for it... Ace Hardware. Scored the proper gauge cable there, too.
Gather this stuff and take it to work with you. Someone at Sky Harbor has a Nicopress tool, just like the one in my roll-away, for a proper swage. I use a light smear of dielectric grease and have had no, nada, zip corrosion issues.
Gawd knows where the FLAPS sources their cables.[smiley=wall.gif]
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I'm sure it was made with pride in China .
It looks like the copper wire was tinned with solder inside the cable end, I'm wondering if acid core solder may cause this ?
I got this cable at O'Reilly's, used to be Checker Auto Parts .
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Acid core solder may very well be your culprit. A have a one-quarter pound package and it's marked NOT FOR ELECTRICAL WORK.
Ace is da place. [smiley=thumbsup.gif]
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I looked at the other end of the cable at the lower right transmission to engine bolt and it looks like corrosion is starting under the nut .
I'll just live with this for two more weeks, then I'm on vacation for six weeks and I'll take it apart and see if I can neutralize the acid with baking soda .
I may end up making my own cable if I can't get this problem solved .
Any idea where I may be able to purchase 4ga copper cable in the limited quantity that I need ?
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The indie NAPA store in my village makes custom hyd hoses and battery cables and/or sells fittings and the cable. Check 'em out. Or perhaps an electrical supply house.