How to test a battery cable?

Post by **scot850** » 21 Feb 2024, 16:28

Again great and very interesting reading. I will tuck this away in my brain cell for future reference for when (if!) I ever get this project to the top of the list.

Many thanks!

Neil.

Post by **BlackBart** » 21 Feb 2024, 16:33

My layman's summary:

Keep adding amps until it starts to smoke. Write that number down, that's too much.

Post by **scot850** » 21 Feb 2024, 19:22

Neil.

Post by **Roger_850T** » 21 Feb 2024, 21:24

I replaced mine a few years ago, I'm trying to recall what led me to conclude it was necessary.
- Low charging voltage at the battery. Alternator connects to starter, which connects to battery, iirc. Just a little voltage loss, but
- Visible corrosion on the wire immediately adjacent to the battery clamp

For identifying a good or bad cable in a salvage yard, I'd probably look for that corrosion in the wire. That's really most of what can go wrong with it, (other than major damage that's readily visible.)

Roger

Post by **scot850** » 21 Feb 2024, 22:57

Like I said, the battery end is covered by a molded rubber boot a bit like thick heatshrink. You would have to cut that off to see the top end.
The other end is likely to have more corrosion as it sits at the back of the starter motor and is closer to the ground, so splashing water is more likely to affect the bare ends of the wire strands at the starter clamp.

Neil.

Post by **jreed** » 22 Feb 2024, 05:36

I remember reading somewhere that one of the contributors to the failure of the crimp connection at the positive battery post is fumes rising from the sulfuric acid electrolyte inside the battery cells reacting with the copper metal in the cable causing corrosion.

Post by **scot850** » 22 Feb 2024, 10:21

I guess it depends on how good the seal is on the +ve battery terminal is. It seems to be good.

That brings about another good point. Batteries used to (and I believe I have seen recently) have a vent hole for off gassing. There is supposed to be a drain pipe for that taking the fumes away from the battery area. When did you last see one of those?? Can you even buy them any longer?

Neil.

Post by **volvolugnut** » 22 Feb 2024, 18:41

If you are asking have I seen the battery vent tubes, Yes, I have them on the V70, my 2001 Mercedes, and the 2009 Smart, Just a rubber/plastic tube through a grommet to under the car.
volvolugnut

Post by **MrAl** » 23 Feb 2024, 05:08

scot850 wrote: ↑22 Feb 2024, 10:21 I guess it depends on how good the seal is on the +ve battery terminal is. It seems to be good.

That brings about another good point. Batteries used to (and I believe I have seen recently) have a vent hole for off gassing. There is supposed to be a drain pipe for that taking the fumes away from the battery area. When did you last see one of those?? Can you even buy them any longer?

Neil.

Hi,

Oh, I don't remember seeing those I must have forgotten them (the hoses).
I do remember seeing one of the battery platforms where the battery sits corroded.

Post by **P80GLT** » 23 Feb 2024, 05:48

All batteries in a confined space inside the car should be vented. V70 with battery in the boot/trunk is vented as pic below

: Battery Vent.jpeg (176.04 KiB) Viewed 222 times

How to test a battery cable?

Re: How to test a battery cable?