Author Topic: battery going dead overnight (Read 5668 times)

ToniJ1960 · « **on:** March 19, 2013, 05:37:15 PM »

The battery in my 78 Pinto is going ded over night the last few days. It hasnt been near as could as it was it doesnt seem like the right time for it to g oout but who knows my cars mad at me one thing after another.

It charges up holds a charge to drive around, one day we push started it and it charged up enough to start again a few times. Im not sure if its the battery or something draining it so Im charging it inside and when I take it to the car again I can try to see if theres any drain on it when I put it in.

Since it does get a charge and hold it at least for a while,Im not suspecting the alternator. Maybe the battery, or one time I had a battery keep getting drained and it was a bad voltage regulator doing it.

Does anyone know a good test to see if it is the regulator?

Pinto5.0 · « **Reply #1 on:** March 19, 2013, 05:46:28 PM »

Have Autozone load test your battery. That will also check alternator & regulator at the same time.

r4pinto · « **Reply #2 on:** March 19, 2013, 05:57:56 PM »

Quote from: Pinto5.0 on March 19, 2013, 05:46:28 PM

Have Autozone load test your battery. That will also check alternator & regulator at the same time.

Might not also be a bad idea to take the battery & alternator off the car & have them tested off the car if it is possible to do that. One easy thing to look for on the voltage regulator is feel it with the car off after it has sat for a while. It shouldn't be warm. Had one go bad on a 78 I had I the regulator was rather warm to the touch even though the car hadn't been run for a while.

ToniJ1960 · « **Reply #3 on:** March 19, 2013, 06:13:19 PM »

That makes sense. Its on the charger now I should know later if it takes a good charge and stays charged. Its drawing 8 amps so I know it got drained pretty far.

I dont gues it would hurt to try unplugging the voltage regulator after I put the battery back in and see if theres any parasitic drain. First thing I should check i s my brake lights a few years ago I had a problem with the new switch sticking.

blupinto · « **Reply #4 on:** March 19, 2013, 06:43:23 PM »

How old is the battery? I learned the hard way this winter that batteries seem to only be good for 4 or 5 years anymore. My battery was ok for driving but the next day it would let me attempt to start the car before it was kaput. I had to replace 3 batteries! They're not cheap, either! Good luck!

HOSS429 · « **Reply #5 on:** March 19, 2013, 07:15:37 PM »

hook the battery cable up in total darkness and watch for a spark .. that would mean a short somewhere .. and a bad connection will allow a fresh battery a full 12 volts to start the car a few times yet not allow a smaller charging voltage to pass and refresh it .

ToniJ1960 · « **Reply #6 on:** March 19, 2013, 07:42:27 PM »

Well one cable was loose so I took it off and cleaned it and put it back on tighter.I should probably go ahead and do the other one before I put the battery back in. The negative is pretty new but I shjould check both ends on them anyway. It did start again a few times after just getting a jump start after driving here and there, I really think its charging. After I shut the engine off yesterday the battery voltage was about 12.7 or 12.8 and an hour or two later it was 12.3 seemed kind of normal I shouldve checked it again at least one more time.

D.R.Ball · « **Reply #7 on:** March 19, 2013, 09:15:44 PM »

Those battery cables do not last long either....Chan ge them when you change your battery. Most of the aftermarket ones (Autozone etc) are crap and do not fit right Have done the test where the engine is running and then disconnect the positive terminal cable( It should ? keep running. Do you have an aftermarket radio installed or had any other work done on the wiring......Th ese days people do not know how to work on "simple " cars even when they are "pros" at installing stereos etc.You have a voltage drop, do an hour by hour check...Is the battery sealed or the kind that you can add water to ? Do not use tap water to service a battery use non mineral water in bottles....

ToniJ1960 · « **Reply #8 on:** March 19, 2013, 09:49:40 PM »

I could check the cables by reading voltage across them with some lights or whatever on I guess.

The battery is one you can take trhe caps off I have them off while its charging and the cells are all at the same level.I havent added anything.

But its been on t he charger 4 or 5 hours now and its still drawing 8 amps same as when I first put it on it.

ToniJ1960 · « **Reply #9 on:** March 19, 2013, 09:51:50 PM »

And I do have a more modern stereo installed I did it myself. The first time it went dead I unplugged it in case thats what it was. I had one one time that would turn itself on somehow it was possessed.

Pinto5.0 · « **Reply #10 on:** March 20, 2013, 09:40:34 AM »

If you do the test checking for spark in the dark make sure your doors are closed(dome lite) & the stereo memory wire is unplugged.

I've also had brand new batteries crap out in under 2 years

r4pinto · « **Reply #11 on:** March 20, 2013, 11:48:33 AM »

Quote from: Pinto5.0 on March 20, 2013, 09:40:34 AM

If you do the test checking for spark in the dark make sure your doors are closed(dome lite) & the stereo memory wire is unplugged.

I've also had brand new batteries crap out in under 2 years

To add on that make sure you put the caps back on the battery before reconnecting. One spark with the caps off can cause an explosive situation.

ToniJ1960 · « **Reply #12 on:** March 20, 2013, 02:47:22 PM »

Thanks the current finally dropped on the charger last night around 1 am, and today the battery still shows over 12.8 the caps are back on and ready to take it back out to the car. The stereo is still unplugged from when I first suspected it to be the cause.

Im going to connect the positive cable to the battery and an old 1157 between the negative post and ground cable and see if it lights or glows. If it does then disconnect the regulator and see if it quits.

Does anyone have a schematic of the voltage regulator? I never have seen one last very long Im tempted to try to repair it. I imagine I have some suitable transistors around somewhere.

r4pinto · « **Reply #13 on:** March 20, 2013, 03:47:25 PM »

I have a 1978 electrical schematic book at home. When I get home I'll go ahead & scan the page for you. PM me your email & I'll send it directly

ToniJ1960 · « **Reply #14 on:** March 20, 2013, 06:12:53 PM »

Thanks Matt I went ahead and bought a new voltage regulator. My test bulb 1157 came on bright before and now its off. So I hope thats all it is.

I have a wiring diagram for all years of Pintos in a Mitchel DVD. I really want just the actual schematic of the voltage regulator itself. This is probably the third one I had to change in this car, over 26 years. I guess thats not bad,but it still seems a solid state device should last longer than that.

If you have a schematic for the voltage regulator itself, I would really appreciate it.

r4pinto · « **Reply #15 on:** March 20, 2013, 07:12:27 PM »

The schematic I have is of the wiring to the voltage regulator from a 1978 Ford Pinto wiring book.

ToniJ1960 · « **Reply #16 on:** March 20, 2013, 07:48:00 PM »

I tried googling for over an hour and cant find a schematic of the actual voltage regulator. I guess I can open the old one and try t o draw a schematic myself.

blupinto · « **Reply #17 on:** March 21, 2013, 10:42:20 PM »

How old is your battery?

wbacon8780 · « **Reply #18 on:** March 22, 2013, 07:05:52 AM »

As blupinto said, How old is your battery?

ToniJ1960 · « **Reply #19 on:** March 22, 2013, 04:08:23 PM »

The battery is about 2.5 years old right on the border I guess for bateries these days.

I had thought everything was ok, the battery didnt drop at all overnight in the house, its not really t hat cold outside, and I stopped the current drain that WAS making an 1157 light in series with one battery cable.

Well its down again though. Going to recharge i tonight leave it in the car outside under simlar weather and see what it looks like in the morning. If the battery stays charged sitting under the hood disconnected, then I guess I can try a smaller bulb or a small resistor and a volt meter to see just what kind of ambient current is there. Maybe it fooled me yesterday and my test bulb wasnt making contact when the light went out.

Back to square one.

r4pinto · « **Reply #20 on:** March 22, 2013, 05:32:24 PM »

Have you had the battery tested?

ToniJ1960 · « **Reply #21 on:** March 22, 2013, 07:06:38 PM »

No I just had it on the charger I have and it seemed fine then I let it sit all night before I took it out it still had a good charge then.

I just was dumb and put a voltage regulator in that I had kept and it was probably bad too. I opened up this one and found a burned out diode and a shorted device that looks like a to220 transistor, but after about an hour of googling (its house marked) I found out its a ST Microdevices regulator IC not a transistor. Nowhere to buy them I can find ( LF40C) so going to OReilly I guess and buy another cheapo regulator.

r4pinto · « **Reply #22 on:** March 23, 2013, 02:03:55 AM »

While the battery seems to be holding a charge doesn't necessarily mean it wasn't hurt or starting to go bad. Best to find out now while it's fully charged if it is bad or not. It's free to have checked & will also eliminate the possibility of the battery being a cause.

ToniJ1960 · « **Reply #23 on:** March 23, 2013, 03:21:52 AM »

I found a diode (1n4004) in the old regulator that was broke in half. Im thinking since the anode was ground its for spike protection. Probably flyback voltagse created by shutting off current to the field coil.

Now, theres a capacitor or condensor if you prefer, that goes on the fender wall next to the voltage regulator. It has a connecor on it, black wire from the capacitor, and yellow on the other end of the connector. The yellow wire is off and I dont know where it goes to. Im afraid that could be why that diode got blasted, if the capacitor is supposed to absorb some of that spike. Where does the other end go to?

oldkayaker · « **Reply #24 on:** March 23, 2013, 05:16:48 AM »

According to the 78 EVTM, the yellow wire from the capacitor connector gets connected to the regulator "A" (armature) terminal. The yellow wire is suppose to have some white dashes on it, may be faded. The EVTM labels the capacitor for radio noise suppression, but should provide some protection for the regulator too.

ToniJ1960 · « **Reply #25 on:** March 23, 2013, 06:21:57 AM »

With that 1n4004 in there reverse biased it was either a heckuva high transient or a reverse polarity spike that blew it in half

Blue79Pinto · « **Reply #26 on:** May 02, 2013, 11:06:49 PM »

I also am having this problem. The battery in the car is brand new. I have replaced the voltage regulator as of two years ago. I never have replaced the alternator though. At idle the brand new batter reads 11.5v to 12v depending. Is this a sign of a bad alternator? I have put a modern stereo which may be part of the drain, but I am going to equip it with a toggle switch to completely turn it off so it cannot get power when the car is on. By the way forgot to mention this brand new battery died overnight while in the car. And after only a few hours of being in it after being charged and run it went down to 10.5V. Any help would be much appreciated.

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Author Topic: battery going dead overnight (Read 5668 times)