Erractic ammeter

[pbarcher]

The ammeter on my '73 swings wildly on startup and above idle it appears to be charging almost to the max, even with a fully charged battery.

It didn't do this before I installed Dave's PLH, HLH and installed a 60 amp alternator with the ZXT plug. I also installed an Alpine PDX F4 100 watt/channel amp at the same time, so I don't know which mod may have affected the ammeter reading.

The car runs fine. Should I be concerned about this?

[steve91tt]

I have a similar setup on my 1973 240Z but if anything my ammeter shows less current that before the installation of Dave's kits. I think you have a problem. If you have a large current load where it shouldn't be you can cause a fire more easily than you might think.

[Mikes Z car]

I can't help think the voltage regulator for the alternator isn't working. This might not be the easiest idea and better logic might prevail but I would try putting in the old alternator as a check of the regulator.

Mike

[steve91tt]

I'm not sure why a bad regulator would cause a current draw through the dash I would check the voltage coming off the alternator to see if it is functioning correctly.

[EScanlon]

Don't forget that with all that "bypassed" circuitry, all the large draw items are now functioning directly from the battery. Therefore the large amount of "charge" going back to the battery is to replace what is being discharged through the relays.

But, if the ammeter is showing a huge charge without the lights, stereo and other items being turned on, then you have a different problem.

Your post doesn't specify if it does it all the time or only with the lights etc. on.

FWIW

E

[steve91tt]

Good point. I guess the extra ammeter deflection could be due to the load of the head unit and amp.

[Zs-ondabrain]

If the meter is showing erratic on start up, and the lights are off, then I would get a volt meter on there and start checking voltage and connections. you gotta remember that the originalmeter is for a 40 amp alternator and you just installed a 60 amp alternator. If there is a surge of any kind, the ammeter can go bonkers (Erratic) and keep doing it afterwards.

So check the output of the new alternator. Check ALL your connections. If you don't mind the extra work, reinstal your stock alternator and Regulator and see if the problem persists. If the problem goes away, then run your 60 amp alt. down to the auto parts store and have it checked. Even Brand New Alternators can be bad Right out of the Box.

If the new alt checks out, and the problem is still there with the Old alternator, then the ammeter may have finally bit the dust.

So test the alt and wiring and get back to us.

Dave

[pbarcher]

Finally got around to having the charging system and battery checked by a reputable shop. I was told that the alterntor was functioning fine, but that the battery voltage was low. The tech said that he suspects a battery leak.

A while ago there were some posts about battery leaks when using the ZXP plug with the 60 amp. alternator in 73 models. Was that issue ever solved?

Peter