Big fuse diag with RS-AJP

[egilkv]

Jooles81 said:

From the graphs, the alternator regulates between 12.5 and 13.3V, instead of 13.6/ 14.4. Why? Could it be that the cables are so old and worn that the resistance is bringing voltage so low?
Julien

Too low charging voltage is a typical issue on very many vehicles, and is the main reason why people need to change batteries every two years instead of every six or more. The standard alternator regulator is a shabby affair. The usual, cheap fix is to add a diode in the regulator sense wire to get the voltage more where it should be.

Since the regulator is internal, any wiring loss to the battery will not be compensated for. You can check this by measuring the voltage between the alternator B+ terminal and the battery plus under heavy loads (e.g. main lights+rear window). The ground can also be bad, but usually that means you have starting problems too.

[Juddder]

egilkv said:

The usual, cheap fix is to add a diode in the regulator sense wire to get the voltage more where it should be.

I've been following this also as my alternator doesn't charge my battery at idle (the AA guy confirmed this with a clamp multimeter a few years ago and seemed surprised by it)

Reading up on the above, which I'd not heard of before, there's a very interesting discussion about the issues and ways to fix them here

http://www.electro-tech-online.com/threads/higher-...

..and more references when talking about Skylines here

Edited by Juddder on Tuesday 30th August 15:44