little red light wont go out, my battery wont charge properly

[pauly_adams]

hey all since doing a l28 upgrade in my 260z 2+2 my little red light is always on, it charges at only 12v or about 16v to 18v it fluctuates depending on alternators, if you disconnect the battery sometimes it dies other times it doesn't i have also changed my alternator but still does the same thing.. does any on know what may be causing this as it is really bugging me.

 

cheers pauly

[Zedman240®]

Are you running a ZX int reg alternator or a ext reg 260Z alternator? Seems like the regulator has shat itself..

[pauly_adams]

i have tried both mind you the one that was installed on my l26 my spare now on the l28 was a internal regulated unit anyway and i had no issues so its got me stumped dimitri.

 

cheers pauly

[Nacks]

Did you bolt the old alternator on to the new motor?

 

What make/brand of alternator is it? Apart from the main battery wire (thick), how many other wires are there on the back of the alternator?

How many plugs/connections? Might pay to take some pics of both and upload.

 

Are your alternators different to one another ie. different brand?

 

12v tells me it isn't charging.

16-18v is WAY too high. It shouldn't normally go above about 14.4v.

 

Don't EVER disconnect the battery while the engine's running. The alternator uses it to sense/regulate voltage. You risk causing some ugly voltage spikes that might wreck any electronic devices on your car.