Battery Problems after Rebuild

[Lazy JW]

Try tightening the belt.

 

[MercuryMarc]

Sorry LJW-
You are also THE MAN!
Both you and Nathan suggested I do what I should have done in the first place.... But it "looked" tight enough...
Thanks again, everyone.
I can get a whole lot of belts (nice ones...) for the price of a new alternator.

Marc in SF
63 Comet Ragtop
http://mercurycomet.net

PS- Plan for tomorrow: move the jumper cables from the front seat to the trunk....

 

[Lazy JW]

Well just so you guys know i have a new ammeter installed (says how many amps the alternater is putting out) and mine is rated as a 70 amps alternater but, only puts out a max of about 55 amps......

Unless you wired the ammeter directly into the output of the alternator it will never read the full output of the alternator. Normal wiring for ammeters places the meter between the alternator and the battery, and in parallel with the rest of the car's wiring.

What this means is that the only current readings you will get are are when there is current flowing into the battery or out of the battery.

Therefore, it is quite possible, and frequently happens, that your alternator is indeed putting out full rated amperage to run your boom box playing all that mind blowing punk rock, and there is nothing left (or very little) to put back into the battery. This results in a low amperage reading on the gauge.

Now, if you hook up your buddies boom box in addition to yours to really impress the girls, your alternator won't have enough juice to maintain the amp flow at that voltage, so total system voltage drops below battery voltage, and current flows from the battery into the system to make up for the lack. This results in a "minus" reading on the ammeter, all the while your poor alternator is working itself to death. This will continue until the battery goes dead or the girls are suitably impressed, whichever comes first. :roll:

In order to read full amps, you would need to run the alternator output wire all the way to the gauge, then from the other side of the gauge all the way back to the alternator. This would result in a lot of voltage drop unless you use REALLY big wire.

A voltmeter is VASTLY more informative than an ammeter.
Joe

 

[Anonymous]

t/y joe didn't realy think of the fact that it probably was it just wasn't showing full output because, of it being wired between the battery and alternater *insert foot here*. Anyways t/y for the explanation and btw i didn't even know what the ammeter was until i installed it lol i just bought the gauge because, it came with an oil pressure gauge and water temp for 20$ so i figured why not lol.

 

[MercuryMarc]

Dead battery this AM.

I drove the care several times yesterday, even as late as 11PM (to go to the all nite post office to mail some chrome trim for a Canadian Comet...) and it worked fine. Started up STRONG!

This morning - just a "click." No juice. Voltage reads 10v.

So.....
I 'm heading out for a new battery.

Marc in SF
63 Comet
70 250/C4
Dual Cupholders

And I'm putting the cables back in the front seat.....

 

[BIGREDRASA]

It never hurts to have a good battery, but.....

Did you do the voltage checks hot and cold as I posted earlier? When I had the problems with my Aerostar, the problem was the built-in electronic regulator in the alternator, and it only failed when hot.

 

[Anonymous]

Leave one battery cable off over night, then hook it up in the morning.

If it starts then you know the battery is good but there is a drain somewhere...

 

[MercuryMarc]

Thanks-
will be out of town for a week but will ty to fix up the ol' Comet when I return. You all have given me lots of good leads.
Marc

 

[MercuryMarc]

Back to the basics...
Charge overnight, disconnect cables in am ---> starts 24 hrs later
Disconnect again---> starts again 24 hours later
Conclusion: battery OK
Voltage 12 volts

Retested for current draw..
(this time I remembered to set my voltmeter/ammeter to amps not volts)
3.5 mAmps current draw!!!!

NOTE THAT I EDITED THIS LINE TO REFLECT THE REAL CURRENT IN MILLIAMPS - ORIGIANALLY I POSTED THE CURRENT DRAIN IN AMPS WHICH IS OF COURSE 1000 X MORE THAN THE DRAIN. Sorry Lincs 200 and thanks Lazy JW


Traced it to the wire "bat" terminal on my 1 wire alternator
so it looks like have a problem with the alternator regulator - possibly a diode?

marc

 

[Anonymous]

See, always do the basic stuff first before you replace anything!


Yes, sounds like a bad diode.

 

[kirkallen143]

You know all my years of playing w/ vehicles, I have never thought of testing for a battery that way by dissconecting the neg and using a test lamp b/tw the two. LEARN SOMETHING NEW EVERYDAY, but it was funny, working on a buddy's bronco and also ended up being a loose belt. Start simple.

Kirk '73 bronco

 

[Anonymous]

be careful though, Kirk.
Some vehicles with clocks and A/C will make a test light flow current when there isn't really a lot of current flowing. That is why you have to go back and disconnect just one item at a time until you find what it is that is drawing the current.

 

[MercuryMarc]

I called Powermaster- 3.5 mAmps is normal for the memory chip in regulator for the one wire alternator.

Must.... Keep...Trying.....

Marc

 

[Anonymous]

I called Powermaster- 3.5 mAmps is normal for the memory chip in regulator for the one wire alternator.

That sounds like total B.S.

If their alternators are of that poor design, then they should stiop selling them.

I would believe .035 amps, but not 3.5 amps. Thta's like leaving the tail lights on!!

 

[BIGREDRASA]

Not to sound repetitious; but, did you check the condition hot and cold?

 

[MercuryMarc]

Big Red-
I have not run the car in few weeks - I am in the "charge, unhook, wait a day, and test voltage, see if it cranks" stage....

So I will now warm it up and test the voltage hot and cold-- thanks for the reminder!

Linc-
I typed 3.5 mAmp which is what it reads on my analog meter. I believe it is 3.5 milliamps, or 0.035 Amps.

What Powermaster Service Tech Support advised:

Measure voltage from "bat post" on alt reg to ground
Measure voltage from starter relay post to ground
Measure voltage from positive battery terminal to ground

And look for voltage drop. He said I can take off the regulator and adjust the output voltage a little if my battery can handle it- maybe from 14.4-14.9 volts.

Still tempted to just get a new alternator and battery....

Ah, the joys of owning a classic!

Thanks again-

Marc

 

[Anonymous]

Linc-
I typed 3.5 mAmp which is what it reads on my analog meter. I believe it is 3.5 milliamps, or 0.035 Amps.

Oooops - Maybe I need bifocals??

 

[Lazy JW]

Linc-
I typed 3.5 mAmp which is what it reads on my analog meter. I believe it is 3.5 milliamps, or 0.035 Amps.

Oooops - Maybe I need bifocals??

Maybe. On page One he typed 3.5 AMPS. On page Two he typed 3.5mAmps. Of course 3.5 AMPS is a significant draw, but 3.5 mAmps is not.
Joe

 

[MercuryMarc]

1000 apologies to Lincs and thanks to Lazy JW. Yes I did type the wrong reading in one post, and I put in bold that it was 3.5 amps when I really meant 3.5 mAmps. I am going to change it to avoid any confusion but will note the change (just trying to limit the confusion, not destroy the evidence).

I need bifocals and better typing skills.....

But it is really a minor current draw of 3.5 milliAmps

On page One he typed 3.5 AMPS. On page Two he typed 3.5mAmps. Of course 3.5 AMPS is a significant draw, but 3.5 mAmps is not.
Joe

Marc

 

[Lazy JW]

I have observed certain digital clocks that drew 500 ma. They will kill the battery in about three-four days. This is the type of clock that has bright red digits. Ok if you drive every day, bad if you park it for a week or more.
Joe