Jump to content
HybridZ

240z alternator and battery wiring


Recommended Posts

Have a 73 240z. Trying to figure out the alternator to battery wiring. I see wire from alternator body goes into the harness, then there is a plug that goes to the voltage regulator. That wire then runs is then tied into the loom of the main harness.

Where is the wire that goes to the battery to charge it? Instead all i see is wire that comes out the harness for my starter, and postive cable from battery to starter along with my ground. Anyone have a picture of stock alternator to battery setup?

Link to post
Share on other sites

The alternator output goes through the large (10g) white/red wire. This wire goes into the cabin to the fuse box, ammeter, and ignition switch. From the ammeter a 10g white wire goes to the starter motor, connecting to the main battery cable through the fusible link. The battery is charged thought the white wire.

Link to post
Share on other sites

IMAG0022.jpgThanks for everyone help. Beermanpete, seems my car is setup the way you stated. I guess the wire i taught was for the starter is actually the fusible link, i have attached a picture, is this the wire? It had no connector on it before was just wrapped around the starter which i guess is why it was not charging the battery, the connection was probably lose. If this indeed is the wire going to hook it back up and test voltage to battery.

I am just use to cars always having a wire from a fuse going straight to the battery terminal.

Link to post
Share on other sites

Download the FSM from xenons30 and study the wiring diagram. Most likely the crimp on that aftermarket connector is bad and the connections are corroded. I recommend replacing it with an appropriately sized Maxifuse. You might also consider replacing the ammeter with a voltmeter. The key part of any of these electrical mods/repairs is quality and clean crimp connections. Finding corrosion free wire to splice into on a 40 year old car can be challenging.

Link to post
Share on other sites

IMAG0022.jpgThanks for everyone help. Beermanpete, seems my car is setup the way you stated. I guess the wire i taught was for the starter is actually the fusible link, i have attached a picture, is this the wire? It had no connector on it before was just wrapped around the starter which i guess is why it was not charging the battery, the connection was probably lose. If this indeed is the wire going to hook it back up and test voltage to battery.

I am just use to cars always having a wire from a fuse going straight to the battery terminal.

 

That wire has the correct connectors on it but is not fusible link wire. You need to replace it with a proper fusible link or the Maxifuse as suggested by Rossman. Fusible link wire is available at most auto part stores. Fusible link sizing is not based on amperage but by wire gauge. My understanding is to use a fusible link that is 2 wire gauge sizes smaller than the wire it protects. The white/red wire is 10 gauge, so use a 12 gauge fusible link wire. If you use the Maxifuse use a 60 amp fuse.

Link to post
Share on other sites
  • 3 years later...

All.

 

I like having an ammeter in the car over a voltage gauge and am in the process of upgrading my 240z to use the '82 70A alternator with embedded regulator.

 

Everyone I talk to suggests it is impossible to do this but I am not sure I understand why.  There is nothing in the stock car that requires current over 30A (the rating of the ammeter), heck even a dead battery wont draw more than 30A.  

 

The reason to upgrade the alternator is to allow us the ability to supply additional devices such as new headlights and electric fans etc. Referring to the wiring diagram --> http://www.atlanticz.ca/zclub/techtips/wiringdiagrams/72_240z_wiring.pdf  My very simple solution to this is to add a wire from the alternator White/Red wire to a new fuse block to be mounted onto the firewall. This fuse block will have the ability to hold 4 fuses, and 4 relays to power both the electric fans and the new headlights.  Placing this fuse block here allows us to maintain the existing ammeter.

 

What am I doing wrong?

 

Thanks  Jim

Link to post
Share on other sites

What you want to do is possible and commonly done. The pitfall is the factory wiring is designed for the 40 amp alternator and can be overheated by the 70 amp alternator in a worst-case condition. For example, if you leave the headlights on too long while parked and need to jump start the car and then drive an hour to get home. The alternator will work hard charging the battery and won't care about the 40 amp wiring. It it want to charge at 60 amps, it will.

 

You should consider upgrading the critical wires along with the alternator upgrade.

Edited by beermanpete
Link to post
Share on other sites
  • 1 month later...

Okay... So it turns out that I purchased a 73 240z with a 60A gauge. Do you think the wiring will hold up or should I add another path to charge the battery and use a diode and fuse in line to ensure the am meter is accurate with a discharge and not accurate when charging.

 

Thanks for your inputs.

It should be fine. The extra 10 amps is not a huge increase. You should service all of the connections in the circuit for best reliability.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...