Big amp alternator and wiring

Electrial is my weak spot with cars. My question is this... Is putting a larger amp alternator such as a 75 amp vs a 55 Amp stock job a danger to my wiring? I don't want to fry the wiring in my car.... But I've added a small sound system. Thoughts? Thanks.

If your wiring is adequate for your 55A, it will be adequate for a 75A.

I wish I knew it was adequate! It's a CMC NOT wired by me..

Don't sweat it. It'll be OK.

Roger that Gordon, thanks... I'm prepping for a 7 hour each way trip. I've ventured across the country in worse!! Hahah

I went with overkill Got a 95 amp Heck they even have 125s now

I just didnt know if I'd over amp something !!!

No, the only 'critical' element would be the charging cable from the alternator to the battery and that should handle it with your existing one.

all that's needed is a 10 gauge wire from your alternator to either your battery of the 12 volt lug on your starter.

Larry nailed it.

Thanks guys!

Rule of thumb....10ga. will handle 30 amps before developing a voltage drop and building up heat..... 12 ga. is good for 20 amp ....14 ga. / 15 a. ...16 ga / 10 a. I ran two 10 ga. wires from the alt. to the starter terminal, just to be safe....

or run one 4 AWG from alt to starter to Battery

I run welding cable to my seat warmers.

This might help you guys out for gauge/watt/amp rating:

http://www.the12volt.com/info/recwirsz.asp

When trying to learn how to wire homebuilt airplanes years ago, the Aeroelectric connection was a well respected reference for many tidbits of info. http://www.aeroelectric.com/ Wire sizes, alts etc are in the site somewhere....haven't dug into the site lately.

I just bought surplus power lines from TVA power and authority. That should work? LoL
What do you mean from the Alt->starter-> battery? That doesn't make electrical sense... Are the Larger amp alt's that CB sells decent quality?

http://www.shoptalkforums.com/viewtopic.php?t=106298

"What do you mean from the Alt->starter-> battery? That doesn't make electrical sense... "

Why? The alternator positive is connected to the starter positive is connected to the battery positive. All the terminals (and both lengths of wire) are at the same voltage, so it doesn't matter how the three pieces are wired together. Saves a couple feet of wire versus going directly to the batter for both.

Hey, look at that, post a reply and suddenly a diagram appears.

Keith:

Please remember, when you're swapping out the alternator, to remove the positive "+" clamp from the battery before starting any work. As shown in the magically appearing diagram above, the alternator is connected directly to the battery at all times, has no fuse between it and the battery and there's one hell of a lot of current available through that lead if it happens to touch metal somewhere while you're swapping things around.

Safety first!

Sorry Gordon, I disagree. When performing any automotive electrical work, always disconnect the negative terminal. Also when welding on the vehicle.

Here is why: http://7faq.com/owbase/ow.asp?GoodEngineeringPractice%2FBatteries%2FDisconnectingTheBattery

I concur with Danny regarding removing the negative cable when working on the electrical system.

Danny, correct me if I'm wrong but I believe that Municipal Power companies always disconnect and switch current via the negative side.

Good advice.

So the starter is hot all the time, and the ground makes it crank?

Keith, no. The starter is hot all the time on your car, as is the hot lead that goes to the alternator. The starter solenoid makes it crank. Also always power at the headlight and ignition switches. Most devices in our cars are positive switched, except the dome light(some cars) and the horn(VW and Speedsters/Spyders). Read the link I posted, it explains why you disconnect the negative, earth, or ground lead.

Larry, I don't know about municipal supplies. But in the telco industry, we use rectifiers to convert commercial AC power to DC. Everything is -48 v DC, and the - or negative lead is switched. Ground is ground or earth, and is connected to the positive side of the battery string(Four 12v in series to make 48v). Once you get used to it it is no big deal to remember polarity. I do get a little nervous installing 60 amp DC breakers in a live panel with new 4 ga. supply leads!

Keith, in a nutshell, the starter has an 8mm stud where the battery cable connects. From that stud, there is usually a wire from the alternator and maybe several other wires that supply 12v positive to other components in yuor car. There is a wire that attaches to the starters solenoid, it's easy to spot as it's attached via a spade connector. That wire is energized with 12 volts when you either turn your key to the start position or push a remote start button on your dashboard. When that wire is energized, it makes the starter work.

Just remember, disconnect the negative side of the battery when working on an electrical component.

Danny - I always disconnect the negative side, but I am not sure of the theory behind it. Can you enlighten us?

Lane, Danny provided a link, it's about 6 posts above your last posting

I'll make it easy for you: http://7faq.com/owbase/ow.asp?GoodEngineeringPractice%2FBatteries%2FDisconnectingTheBattery

Thanks! I always did it to avoid "spanner" flash. Now I know that's the "engineering" reason.

Don't forget to add a ground from the alternator case to the cars frame.. Belts and suspenders guys!! Cover the weak links..