Ammeter pegged to the right

[Patrick H.]

Re: Ammeter pegged to the right

Go to Radio Shack and buy adapter clips that have a hole in the back for the pointy end to slide into. Voila clips. There sia Radio Shack by you, right? I thought Holland Michigan was a big town. We are 60K people and have two Radio Shacks.

I knew it moved, but didn't know the new location until you made me look.
I'll check it out.

Patrick

[Donald O.]

Re: Ammeter pegged to the right

what about a couple of old hemostats (roachclips)? They also make great heat sinks when soldering.

[Patrick H.]

Re: Ammeter pegged to the right

what about a couple of old hemostats (roachclips)? They also make great heat sinks when soldering.

How you gonna get that to attach to those battery cables or even the bolt head on the cable?

I'll look for some sort of clip, or just do my best with the pointy leads.

[Patrick H.]

Re: Ammeter pegged to the right

FYI, resting voltage today was 12.8

I started the car and the voltage went to 17+ volts. In addition I started to smell boiling battery acid. I turned off the car.

I've disconnected the alternator belt for the drive to the alignment shop tomorrow. I assume (?) it's the regulator that needs replacement. So, which piece is the regulator? I've taken apart a few of these but don't know which one it is.

Patrick

[William C.]

Re: Ammeter pegged to the right

Patrick, as unfamiliar as I am with these cars, it looks like per the assy manual the '72 uses a regulator internal to the alternator. In that case, you can first disconnect the 2 way connector from the alternator and see if the charging voltage drops to battery voltage level, if still high, good chance of an internal short in the charging module in the alternator and you will have to remove the large red B+ lead from the alternator also, (and tape it well and out of the way)

[Gerard F.]

Re: Ammeter pegged to the right

Patrick, as unfamiliar as I am with these cars, it looks like per the assy manual the '72 uses a regulator internal to the alternator. In that case, you can first disconnect the 2 way connector from the alternator and see if the charging voltage drops to battery voltage level, if still high, good chance of an internal short in the charging module in the alternator and you will have to remove the large red B+ lead from the alternator also, (and tape it well and out of the way)

That's what I thought, the 72 regulator is internal to the alternator. I that case, it looks like Patrick has an alternator problem plus a fried battery. The battery is not going to last that long at 17 volts.

To make things easier, try one of these to monitor charging and battery condition:



Less than 20 bucks at Walmart, and you don't have to fuss around with ammeters and cables.

[Terry M.]

Re: Ammeter pegged to the right

Patrick the regulator is the part that the field connector plugs into. When out of the alternator is approximately triangular in shape and has two tabs for the field connector to plug into.

Judging tip: The OEM regulator is date coded and the date can be read when the alternator is installed on the car by removing the field connector and looking down the resultant opening.

[Jack H.]

Re: Ammeter pegged to the right

That says a BUNCH!

The alternator is delivering MAX output. You shouldn't see battery voltage climb above 15 VDC...

You have two probable causes:

(1) The internal V-Reg is damaged and telling the alternator to deliver above normal output.

(2) The 'nest' is defective with the wiring providing the alternator (and its internal V-Reg) the battery sense signal (what is the current battery charge state?) incorrect information.

On #2, suppose for a moment that there's a flakey connection in the battery sense wire. Sometimes the path is good/solid and the alternator & internal V-Reg actually 'see' the battery. BUT, other times, the sense path open circuits resulting in the alternator & internal V-Reg to 'see' a TOTALLY DEAD battery (approximately 0 VDC).

When the wiring path fails, the internal V-Reg is going to tell the alternator to run FULL TILT to charge a SERIOUSLY depleted battery! Such is NOT atypical of Shark era alternators with the 2-conductor side terminal (one lead wire is the battery sense line) where there's faulty contact and/or a frayed/fatigued wire to terminal interconnect...

Plus, if #2 IS the root cause, this is a situation where pulling the alternator and taking it to a shop/parts store for test, can result in you chasing your tail! Expect the alternator to test OK, but the problem to come/go when you re-install the alternator using the same 'bad' wiring interconnect components...

[Patrick H.]

Re: Ammeter pegged to the right

Plus, if #2 IS the root cause, this is a situation where pulling the alternator and taking it to a shop/parts store for test, can result in you chasing your tail! Expect the alternator to test OK, but the problem to come/go when you re-install the alternator using the same 'bad' wiring interconnect components...

However, if the alternator tests OK then I can narrow it down to a wiring issue, correct?

Patrick

[Dick W.]

Re: Ammeter pegged to the right

Patrick, it has been my experience with these regulators, when they go bad, is either they do not charge at all, or they go wide open as yours is. That same regulator is used on 145 amp alternators, had one of them go bad, cooked every electrical component including a $1,200 two way radio. Odds are it is the regulator

[Patrick H.]

Re: Ammeter pegged to the right

Patrick, it has been my experience with these regulators, when they go bad, is either they do not charge at all, or they go wide open as yours is. That same regulator is used on 145 amp alternators, had one of them go bad, cooked every electrical component including a $1,200 two way radio. Odds are it is the regulator

It was the regulator.

I purchased a new one (a bit over $16 at the FLAPS) and installed it in the alternator late last week. I was thankful I'd replaced the bearings earlier this year as that made it easy to take the alternator apart. Installed new regulator, and today put the alternator back in the car. Ammeter is right back at normal now.

Patrick