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I'm planning on replacing the battery cables (and clamps) on my 1980 300D. Is there a certain "gauge" I need, or any specific kind of cables that are required? Can anyone recommend a certain brand or place to get the cables from? Is there anything wrong with just going to an AutoZone and getting AC Delco cables or whatever brand they carry?

I've got some bad corrosion going on, particularly on the negative side. I have a new battery that is just a couple of months old, and I didn't use the car for a couple of days, and yesterday it didn't have enough power to start. I had all of the electrical systems checked when the battery was replaced, and everything was ok. The previous battery was not even a year old and the same thing happened, so I'm just trying to do anything I can. I know that corrosion can prevent the battery from being recharged by the charging system, so I'm hoping the cables are the problem.......
 

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Alternator check

Have you checked the alternator? A simple test is to start the car (or jump start it in your case) and then disconnect the postitive terminal. If the vehicle continues to run, then the alternator is OK, but it you disconnect the positive terminal from the battery and the car stalls, then you know where the problem lies.

Also make sure that you purchased the proper battery with enough cca (cold cranking amps). This is even more critical if your car is diesel. I believe 700 to 1000 cca is average for most diesel engines but read the owners manual to make sure. It's my understanding that you can't hurt the electrical system by installing a battery that has more cca than is required by the manufacturer (which is why the spec usually says "minimum cca required). The spec on my old Chevy Silverado 6.5L Detroit diesel required 2 batteries with around 750 cca each but I installed 2 batteries that had 1100 cca each and I got many trouble-free miles out of that truck.

Corrosion has more to do with the electrolytes in the battery itself than the battery cables. The positive and negative charges on the battery terminals react with other electrolytes and minerals found in water. increased humidity or lots of rain means more reactions which means you'll have to occasionally pull your battery cables off and use a wire brush to clean off the battery terminals and the inner contact surface of the cables. Non-conductive corrosion will prevent juice from reaching your starter. Also, make sure your starter is grounded properly. This is often overlooked and hundreds of dollars are wasted when the fix is simple. Hope this helps.
 

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The battery is an Interstate 750 CCA 900 CA. As far as the alternator goes, it was tested, along with the starter and voltage regulator, and everything checked out ok. I may just have to do your test, just in case. I don't think it's the cables, but I'm going to change them, just to be sure. They were an old, used pair put on by my mechanic when the prior ones weren't allowing the car to start for some reason. I don't know what specifically was the problem with those cables, though.
 
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