Charging issues

[MarcusDatsun]

hello I have a 1982 280zx turbo model. 

My battery isn't charging anymore and only reading 10volts when running. The alternator is newer so I checked the posts on the alternator and it reads 15.1volts.

I checked the black fusible link under the ACC fuse cover and it only reads 8 volts. As far as I understand the alternator runs to here then the battery. This is my very first project car so please excuse my ignorance. 

Is there anything I'm missing or any tips to point me In the right direction? Thank you!

[SteveJ]

How old is the battery? Can you post photos of the fusible links?

[MarcusDatsun]

Hm I think its about 1 year old. I purchased the car recently so not 100% sure on its history. 

I can post photos tomorrow, it's currently stuck at my job. I only took off 1 fusible link, the black one, and the sheath for it crumbled away. 

I did get some new fusible link wire and tried it and it didn't change the voltage. 

[AK260]

You may have a break before the fusible link, unplug the battery terminals and check continuity / resistance from the alternator, to fusible links and any junctions along the way to battery cables. You should find resistance of around 0.1-0.3 ohms depending on the state of your wiring. Also the connections tend to corrode and cause huge resistance (huge being a relative concept here).

The voltage regulator at the alternator wouldn’t be holding 15v if the battery was getting charge. I strongly suspect the 8v you see at the fusible link is from the battery and not the alternator.

It’s not a complicated circuit, so I’m confident you will find the issue with a little bit of tracing.

[MarcusDatsun]

Okay thank you I'll give that a shot. I assume I should be focused on the black fusible link under the ACC box and not the others? 

[SteveJ]

The black fusible link carries the current from the alternator to the battery.

If you haven't done so already, download the EL chapter of the FSM: http://xenonzcar.com/s130/FSM/1982/EL.php

Also check the resistance from the battery negative post to the ground post on the alternator. Bad grounding can cause lots of problems.

[Zed Head]

16 hours ago, MarcusDatsun said:

I checked the black fusible link under the ACC fuse cover and it only reads 8 volts. As far as I understand the alternator runs to here then the battery.

Which side did you check?  Check the wire that feeds the link.  Looks like a white one.  And it connects via a plug that could be disconnected or corroded.  Follow the path back to the 15.1 volts.  

The FSM is available here on the forum also.  https://www.classiczcars.com/files/category/14-280zx/