Battery to Starter wire. What size?

[Brother]

What size does this have to be? It looks like a 4-8 gauge wire on my 914. I wonder if it would work just as well with a 10 gauge.

[yelcab1]

Not really. 10-gauge is way too small. It may work now but won't last long. I would stick with the original size.

[Brother]

What would happen? Would the wire just heat up too much?

[911pcars]

According to some charts, the current capacity of 10 ga. wire is about 50 amps.

Since a starter motor can create 200-250 amps of current flow, a large conductor is required.

An attempt to force 200A through 10 gauge wire will result in excessive resistance, then excessive heat, then smoke, then fire when the PVC insulation burns - more if combustible materials are nearby.

Since the battery cable path is from trunk through tunnel to starter, look for symptoms of car burning in those areas when cranking the engine.

That's why.

Sherwood

[Brother]

Sold, Sherman.

I still have plenty of slack from the original. I'm just trying to decide whether to shorten it up or send it from the starter to the engine bay to the rear trunk. As it is, I can shorten the wire by about a foot and just run it through the floor of the trunk.

Maybe I can find some 4 Ga. wire. The NAPA store here didn't have any. Mostly I'm just trying to find a convenient way to use the positive terminal that I have. I think I should go look for a car audio multiple 4 Ga. input terminal.

[Zeke]

Welding leads work great. And, if you have a set (or an orphan) of old POS jumper cables, often times they have the ga. wire you need.

[Brother]

Good ideas, Milt.

I'm trying to up the level of my craftsmanship so I'm really trying to do it well and make it look good.

[Brother]

I ended up using the OE cable. I rerouted the wire and drilled a hole in the trunk. I ran the wire through a grommet and into the battery terminal. There was enough slack that I cut about a foot off the original wire. It took almost that far down to not having any more noticeable corrosion.

[HawgRyder]

Just a quick comment from an old electronics tech.....
When you do any wiring on a car (or anything else)....and you are about to make a connection....ask yourself one question...would you be willing to lick the wires with your tongue?
Don't lick....just look at the wires...are they clean?
Are they corroded?
If they are dirty, corroded, or not stripped back far enough to get a good connection, they will HEAT!!!
Hot connections are not good.
If you are having starter probs and one or more of the connections are getting hot, those connections are acting like resistors...dropping voltage.
The tongue test is really important when making the ground connections on the engine and the body.
My Canadian $.02
Bob

[scottbooth]

I don't know the exact size either. But I also need to replace my cable. Besides the plan to reroute it so I can put the battery in the smuggler's box, while doing other work I noticed that the insulation is cracking back near the starter connection. Lucky that I caught that one before something bad happened.

Here is a source for cut-to-length battery cable of various sizes.

http://www.wiringproducts.com/?target=dept_78.html&gclid=CPv5opCTnYsCFR6AWAodeWMFUg

On a different page, they also sell battery terminal clamps with pre-installed solder slugs, so all you need to do is heat the clamp with a torch and stick the wire in. Probably easier than trying to make that connection by hand.


Good luck
Scott