TR2/3/3A tr3a electrical troubles

[Jim Lee]

Re: Groundless!!!!!!!!

BUT THERE IS MORE!!!!!!!!!!!!!!

I forgot to share what might be some very important information. I converted the car to using the generic GM alternator a while ago. So, I have an All-American negative ground system and a substantial wire that goes from the 'in' terminal of the solenoid to the "batt" terminal of the alternator. It just dawned on my balding head that this is the only other electrical part of the equation that I have not checked out. I am going to check the continuity of the wire from the alternator to the solenoid. Then see if there is any way to check the resistance of the alternator and/or remove it to take it down to my friendly auto parts place and have it tested.

Thanks again,
Jim Lee
1959 TR3a

 

[Geo Hahn]

Re: Groundless!!!!!!!!

On my '3 the ground cable has a toothed lock washer under the bolt holding it to the chassis and of course the paint scraped away from the area of contact.

Yes, I do recall Branded & the theme song. Those are probably occupying brain cells that I could have put to better use somewhere along the way.

 

[Jim Lee]

Re: Groundless!!!!!!!!

I am not understanding this but when I disconnected the "Batt" wire coming from the Alternator all of a sudden everything is working as advertised. By 'everything' I don't mean that I have got all my pieces back together and am driving down the road BUT I can see 12 volts on my meter when I have the positive lead on the battery terminal and touch the negative to anywhere on the car. Also, instead of absolutely nothing happening when I turn the ignition key on, it lights up full strength and the fuel pump starts pumping gas out like it did when it was alive and well. So, there is a short in the alternator? Let's take it out and down to Advance Auto to have it tested. They test it...and it is working great!!@#$$@!#@!!!!!!!!.

Ok, but for $44.00 I am getting a new one. Brought it home. Hooked it the wires up without actually installing it, which will take some time, and everthing appears to be back to normal. Tomorrow, or later tonight, I will put the new alternator in and see if everything really is 'normal'.

This just gets more and more interesting.

Thanks,
Jim Lee

 

[TR3driver]

Re: Groundless!!!!!!!!

Jim, from your description, I think there is an intermittant open (bad connection) in the ground strap from the battery to the body. Possibly even it's not making good contact with the battery post. Most likely it's just coincidence that it decided to start conducting when you disconnected the alternator. (Obviously I hope, the alternator has nothing to do with starting the car, and would have melted to slag if there were enough of a short in it to pull your battery voltage to 0.3 volts.)

When the problem comes back, put your meter between the actual battery ground post and the end of the ground strap, then between the post and the bolt through the strap. That should tell you if it's the strap itself, or contact between the strap and the body.

Remember that paint, lead oxide and rust don't conduct very well at all, so it's quite possible to have a mechanically solid joint that doesn't conduct worth a darn. It takes a clean metal to clean metal joint to carry the current. If your firewall is nicely painted where the ground strap attaches, that might well be the problem.

 

[Andrew Mace]

Re: Groundless!!!!!!!!

My TR3 is GROUNDLESS!!!!!!!!!!!!!!

Anyone remember the show "Branded" with Chuck Connors? I am singing the theme song to that but substituting the word "Groundless" in. "What do you do when you are groundless, and you know you're a man?".

<span style="font-style: italic">Al-ter-na-tor died?
in his T-R-3.
And they say he ran away.

Groundless, scorned as the one who ran....</span>

Thanks, I'm here all week. Try the veal.

(Apologies to, well, just about everyone, especially original composer Dominic Frontiere and lyricist Alan Alch.)

 

[Jim Lee]

Randall was right on it!!!!!!!!!!!!!

Randall, and others, were right to suspect the battery that passed the 'load' test at Advanced Auto with flying colors.

Randall wrote:
"Also to be clear, my battery passed the store's load test as well; even though it was defective. There's just no substitute for actual in-circuit real-world testing. The store's load test is only 100-150 amps, while a healthy TR3 starter draws three times that much (initially)."

I think that battery was either really, really, dead or defective in some way that I have never come across. I swear to Buddha that I was consistently unable to get a good ground to that battery without going to the negative post on the battery. That was very strange.

Positive lead on positive post of the battery. I could not ground it and get the 12+ volts that the battery had (in some way, shape or form) without grounding it to the battery's negative terminal. What the heck does that mean? I thought it meant I had a bad ground whereas it appears I had a bad battery. I finally hit pay dirt when I borrowed another cars battery. All of a sudden everything is working with a brand new super duper battery.

So I have to conclude, for now at least, that there was something wrong with my battery that could not be detected by a load test at the auto parts store? That is as far as my knowledge goes right now.

The car is running like unto a sled on snow. Never better. I do want to write another post to make sure that my Delco cheapo alternator is hooked up right and doing its thing. With my vacuum of knowledge on what the cause of my batterys' demise was, I remain suspicious of the alternator.

Can an alternator kill a battery? It (the alternator) seems to be working fine to me. I am measuring the voltage with the car off (about 12.5) then runnng. When running it is in the teens when idling. Does that sound kosher?

I will never trust a load test again. I have to admit that I thought Randall was being paranoid. I imagine that a load test is a good test for the majority of battery problems. Just not for mine.

Thanks to all who responded.
If anyone is using an alternator please email me.
I want to compare what I can see with a voltmeter with what you are seeing.

Thanks very much,
Jim Lee

 

[TR3driver]

Re: Randall was right on it!!!!!!!!!!!!!

Can an alternator kill a battery?

Sure.<div class="ubbcode-block"><div class="ubbcode-header">Quote:] I am measuring the voltage with the car off (about 12.5) then runnng. When running it is in the teens when idling. Does that sound kosher? [/QUOTE]As long as it's low teens. As much as 14.5 is OK while the alternator is cold, but it should drop to around 14.2 after it warms up. (This gives faster charges in cold weather.) 15 will kill a battery in relatively short order.

Likewise, leaving it chronically undercharged will eventually damage the battery. It needs to hit at least 14 from a cold start (although hot can go a little lower than that).

Right, Art?

And just a thought; your bad ground might have been a broken conductor inside the battery.

 

[Jim Lee]

Battery autopsy?

Oh no. 15 is enough to kill? Are we talking at idle (about 1000rpm) less than 15 volts? It can go higher at higher rpms right? I was seeing higher teens but it was warming up and the choke was on so the rpms were 2 or 3k. Is there anything I can put between the alternator and battery so I do not have to worry about it over charging and hurting the battery or is that all up to the internals of the alternator? What happens to a battery that gets overcharged? I am wondering if it ends up dying an ugly death like my last battery. That battery by the way was no spring chicken. It was at least 3 or 4 years old and I am thinking it might have been smarter to keep it instead of trading it in for core in case there is some tricky way I could do an autopsy and find out the cause of death. I am worried that it was not quite a 'natural' battery death.


Thanks,
Jim Lee

 

[TR3driver]

Re: Battery autopsy?

The battery doesn't know anything about engine rpm ... it's the job of the regulator inside the alternator to control the output voltage under all conditions. Sounds like yours has failed.

Anything over about 14.4 volts at the battery (exact value depends somewhat on temperature) will cause "gassing", where some of the water in the electrolyte is converted to hydrogen and oxygen. This not only presents a danger of explosion, but increases the acid concentration in the electrolyte, which will eventually eat the inside of the battery. And in most modern batteries where you cannot add water, it also lowers the level until some or all of the plates are no longer immersed; which reduces battery capacity and makes the remaining area work harder.

Since you've bypassed the ammeter, you should probably finish the job and install a dash-mounted voltmeter. It will give you some idea if the alternator is overcharging.

Or, what I did was to add a shunt across the original ammeter, to make it read full scale for about 60 amps. Then I could connect the alternator so the charging current appeared on the ammeter. A constant high charge is an obvious indication that the regulator has failed. (Tho I used an old Ford alternator with an external regulator, and it usually failed the other way

)

PS, gassing can also spray battery acid out the vents, which is why so many TRs have acid damage just above the battery box.

 

[NickMorgan]

Re: Battery autopsy?

Jim,
Can you put your old battery in the car that you borrowed the other battery from to confirm that the old battery was faulty? That would eliminate an intermittent fault with the wiring.
Nick

 

[Jim Lee]

Shunt across original ammeter

Randall,

Can you point me to details on doing this?
"Or, what I did was to add a shunt across the original ammeter, to make it read full scale for about 60 amps"

Thanks very much,
Jim Lee

 

[Jim Lee]

Re: Battery autopsy?

Nick,

Excellent idea. I will stop by my auto parts place and see if they have not shipped it out as a core yet.


Jim Lee

 

[TR3driver]

Re: Shunt across original ammeter

Can you point me to details on doing this?

Probably on a web site somewhere, but I don't know where offhand.

The concept is that the ammeter has a small amount of resistance, so if you add a wire of the same resistance across the ammeter terminals, only half the current will flow through the ammeter and so the reading will be half the true current.

Rather than trying to measure and calculate, I used a "cut and try" approach. Turned the headlights on and noted the ammeter reading, then played with the shunt until the ammeter reading was roughly half the original reading. My original shunt wound up being 3 strands of steel "handy wire" (aka baling wire if you grew up in farming country) just long enough to reach across the ammeter terminals. That worked fine for over 10 years, but later when I had the panel out for powder coating; I replaced the shunt with a length of copper wire. Somewhere around 3" or 4" of 16AWG as I recall, but of course your ammeter might not be the same as mine.

 

[Jim Lee]

Re: Shunt across original ammeter

Ok, I just ran out to the garage and it is now measuring about 14.5 volts.
I have two voltmeters and when I first hooked one up it was dancing around in the late teens, 16,17,18....after a minute or two it seemed to 'settle down' to the 14.5 volts. I am going to rehook up the ammeter because I'd really like to know what it is sending....if not the actual amps then at least a relative signal. I am also thinking of getting an analog voltmeter at my local hardward store. The digital thing just gets too nervous for me. It samples too often. I would rather see an average of the Voltage over a few seconds.

So I think I am on the road to recovery. My best educated guess is that I had a bad battery....which of course begs the question.....forget it. I am just going to ride and enjoy the Carolina Fall that never seems to end.

Thanks to all and keep them on the road where they belong.

Jim Lee

 

[DNK]

Re: Shunt across original ammeter

See second post
but I am gloating as I have no clue on + ground vehicles. TOOOOO long ag0 and a lot of brain cells more.

 

[TR3driver]

Re: Shunt across original ammeter

but I am gloating as I have no clue on + ground vehicles.

If he's running an alternator, it's dollars to donuts he's also converted to negative ground. There are such things as positive ground alternators (some units can even run either way) but they are mighty scarce and the trivial conversion to -gnd not only lets you run a common-as-dirt alternator, but all sorts of other electronics like stereo, CB radio, etc.