why did my 41 plymouth flathead that was always positive ground all of a sudden turn negitive

[Joe Cocuzza]

1 hour ago, JohnnyMaryjo said:

i used the meter it says  - 6.16

 

again it says minus 6.16 on the meter now what to do

thanks

Johnny

Just to be perfectly clear in what you are saying.

Connecting the meter with the RED probe of the meter to the (+) POS post of the battery and the Black probe of the meter to the (-) NEG post of the battery you are reading (-) negative voltage on the meter, correct?

[JohnnyMaryjo]

On 7/18/2022 at 10:44 PM, Oldtech said:

I'm a little suspicious of your charger.  As advised, check the battery with a meter type tester. and beg or borrow an old fashioned charger to charge it with. 

here is what the meter is saying when hooked to the 6 volt battery  minus 6.16

I hook the red to pos. and the blk. to neg

if this is correct now what .

thank you al

johnny

[JohnnyMaryjo]

i used the meter it says  - 6.16

 

again it says minus 6.16 on the meter now what to do

thanks

Johnny

[JohnnyMaryjo]

On 7/19/2022 at 8:47 AM, EmTee said:

STEP #1 ^^^

i used the meter it says  - 6.16

 

again it says minus 6.16 on the meter now what to do

thanks

Johnny

[Bloo]

Welp.... Try to save the battery. Put it in the car and turn the headlights on for a few hours. Get it really dead and then try to charge it the RIGHT way. You will need it to be REALLY DEAD for that charger to start charging, and it probably still won't start charging. Maybe you get lucky and it will start charging.

 

If and only if the charger wont start charging you need another 6v battery and jumper cables in PARALLEL with your battery as a temporary measure to fool the charger. That means (-) > (-)  and (+) > (+) so the charger will see something sort of close to 6 volts with the CORRECT POLARITY and start charging. You might also be able to tape 4 D cells in series   - (-)(+) > (-)(+) > (-)(+) > (-)(+) +  like Frank suggested because 4 d cells in series makes about 6 volts, and then hook your homemade series string in PARALLEL to the 6v battery (-) > (-)  and (+) > (+) like you would with another 6v battery and jumper cables. The only reason to do any of this is to fool a smart charger into starting up. Then unhook whatever you used to jump and let the charger finish charging the battery.

 

Or, you could get a real (old, dumb) battery charger like I posted pictures above. If you are going to have an old car you need one anyway. It will start trying to charge no matter what without any shenanigans. The only trouble is you might not just find one right away.

 

My little battery maintainer (the one that looks exactly like your charger except the color of the plastic) is a 1.5 amp charger. If your battery is an 80 amp/hour battery (a good guess), in a perfect world under perfect conditions, it will take that charger a little over 53 hours to charge the battery. In reality, thanks to natural laws, batteries do not always take what a charger is trying to give them. Also the battery will have to be far more dead than it could ever be run under normal conditions in order to get it to charge reversed. I would expect it to take 2 or 3 times that long with that charger, or about 107-160 hours. That is another good reason to have a real battery charger around.

 

EDIT: Before you do any of this, take the 3 caps off of the battery and look down the holes at the acid/water mixture. Are the plates of the battery sticking up out of the acid/water? If so, add distilled water until the plates are just covered, then proceed as above.

 

Edited July 21, 2022 by Bloo (see edit history)

[EmTee]

What Bloo said ^^^.  But, if your battery is more than 3 or 4 years old, you might want to think about just trading it in for a new one.  That said, I'm really curious now to see whether you're able to resurrect the battery you have, but I also worry that it's been so badly compromised that even if the polarity is corrected it will have a drastically reduced capacity and be unreliable when it comes to starting your car.

 

Do, however, scout local garage sales, Craigslist and/or Facebook Marketplace for an old-fashioned 'dumb' 6/12 volt battery charger.  I have an old 10-Amp Schauer like the one pictured below.

 

[Frank DuVal]

Yep, it has been charged backwards. As Bloo says, put battery in car correctly and turn headlamps on. When the battery is dead, take the battery back out of the car and follow Bloo's instructions above.

 

Excellent choice in meters, and starting to learn troubleshooting. A+👍

 

 

[m-mman]

Whew, you, your car has managed to achieve something that is almost purely theory. Ok, bloo gave you instructions for how to drain dead (must be fully dead) and try to reverse it.  

 

You might be thinking "Sheesh this is what I told them two days ago".  But I want you to understand again what you are doing. You are going to fix your car by testing and proving, not guessing.

When you go through this sometimes frustrating diagnostic process (sometimes actually mentally painful), you will be gaining important skills that will help you better understand your car and then YOU will be able to better fix it in the future. And appreciate it better too, it wont be so strange. 

 

As mentioned, looking for a more appropriate charger should be on your list, but we will stay with you as long as you keep trying. Some things we do not know about you however that will factor here, is how much money you have to spend on it. 

 

We ALL started out young and poor and have skills and techniques in our back pocket to get things done very cheaply and crudely.

However as you develop into a serious car collector you will learn very quickly that in old cars, there is a balance between TIME and MONEY.  You are facing one of those crossroads currently.

Discharge completely and then work to recharge the battery . . . . as bloo explained this might take 160 hours or approximately 7 days on your little charger (maintainer). A better charger will do the job faster but you will have to buy a better charger and that costs money.

 

Scrap this battery and buy another is a choice but as I remember this battery isnt that old and again that will cost money.  The BEST thing? IN TIME?  Well that would be to get both a new battery and a good high quality charger, but this is also the most expensive.   Time vs money, how much of each to invest. . . . . ? This becomes a personal decision.

 

Just let us know (as we go along) what works best for you and we will be happy to keep working with you. 

[JohnnyMaryjo]

On 7/17/2022 at 4:45 PM, Bloo said:

Sounds good to me.

 

On a positive ground car, the positive cable goes to the chassis. The battery charger does not care about any of this. You always hook the red charger lead to the positive marked post on the battery. It is the battery you are charging, and how the car's electrical system is wired need not be considered when charging the battery with a battery charger.

 

Check as you outlined with a meter. Red meter lead to positive post and black to negative post. Proceed as you posted above.

 

If it is reversed, the battery may be toast, but the best way to try to save it is the method you posted above. I would only add that if you have an old fashioned "dumb" battery charger, use it! Some smart chargers will refuse to charge when the battery is completely dead, and it will be completely dead after you run it down with the lights. Letting the battery sit dead while you figure it out is bad for the battery. A possible workaround if that happens, and if you only have a smart charger, is to temporarily hook a second 6V battery in parallel with some jumper cables, and that brings the voltage up enough to get the smart charger started.

now what to do ?

 

[JohnnyMaryjo]

please help

[Larry Schramm]

Years ago I had a battery that had the same problem & I did not have a lot of money at the time.  I ended up just hooking the battery cables from the vehicle to the terminal that read the proper polarity.  I then took a paint stick and remarked the polarity of the battery. 

 

At the time problem solved.  Battery worked in that car for a number of years until I sold the car. 

[JohnnyMaryjo]

On 7/21/2022 at 12:48 PM, JohnnyMaryjo said:

i used the meter it says  - 6.16

 

again it says minus 6.16 on the meter now what to do

thanks

Johnny

I tried to charge the 6 volt battery ( out of the car ) the charger will not charge it  on positive  ( the charger says there is a problem

I even made sure the battery was completely dead

does this mean the battery is toast

[EmTee]

Looks like you need to connect another 6V battery in parallel to fool the 'smart' charger, as others said previously.

 

Or, buy this: https://www.ebay.com/itm/175341854891?epid=1941829336&hash=item28d33060ab:g:Ve0AAOSwvOhixFe0

 

Edited July 24, 2022 by EmTee (see edit history)

[JohnnyMaryjo]

On 7/21/2022 at 1:43 PM, Joe Cocuzza said:

Just to be perfectly clear in what you are saying.

Connecting the meter with the RED probe of the meter to the (+) POS post of the battery and the Black probe of the meter to the (-) NEG post of the battery you are reading (-) negative voltage on the meter, correct?

yes that is correct.I let the lights in the car drain the battery  but the battery charger will not chargew the battery?

[JACK M]

Sounds like the mechanic must have left the lights on and was able to recharge it backwards.

As mentioned, almost impossible.

Also as mentioned, you probably won't be able to use one of the new 'Smart Chargers' to bring it back around.

[Frank DuVal]

43 minutes ago, JACK M said:

As mentioned, almost impossible.

Not almost impossible!  And that is the exact scenario, completely dead battery, connect alligator clips backwards not using a bright light to see, walk away, come back and start car. I've heard about it more than once in my shop career. 

[Porsche 68]

Wow just go out and buy a new battery and be done with it !!

[m-mman]

14 hours ago, Porsche 68 said:

Wow just go out and buy a new battery and be done with it !!

Well sure, a brand new Optima and a professional grade charger would certainly do the trick.

 However the OP is a new enthusiast and seems to have a limited budget.  We are trying to walk him through the most basic, most simple most inexpensive steps first.  

it’s where we all started.  

[keithb7]

I got tired of fighting with new fangled digital battery chargers. I found an old manual type.  Brand new.  Century brand. 6V 15A. No auto shut off. No load sensing. Just blast it with pure raw amps. Gets the job done well and lickety-split too.  If a person needs to be warned not to drink battery-acid, this charger is not for you. 
 

 

Edited July 26, 2022 by keithb7 (see edit history)

[m-mman]

Hi Johnnymaryjo,

I don't know if you have become disgusted with your car or life has just gotten in the way (FYI - these conditions have happened to ALL of us) But I thought I would just review where I believe you are with your project, and lay out a plan for what to do next. 

 

First - There was a question about whether your battery had actually reversed polarity. 

You bought a volt meter and determined that it was actually reversed. 

The plan to correct the condition was to drain the battery completely and recharge it in the correct polarity. 

 

Two checks - You said that you drained the battery (left the headlights on) BUT you did not prove that you had by using your voltmeter to check that the voltage was indeed zero. 

 

You next connected your battery maintainer (I dont think it should really be called a charger) and discovered that it wont actually charge the battery. This because it is a "smart" charger. It wont charge if the polarity is reversed AND it wont charge if it cant sense SOME voltage from the battery. 

The suggestion was to buy an old fashioned actual CHARGER. No AI, no circuit boards, no foolproof safeguards, these older chargers just put amps into a battery. If you plan to continue in the car hobby buying such a thing will not be a waste. Hobby cars are parked more than they are driven and batteries are always going dead for a million reasons. If you have an old car you will always need a good battery charger. 

 

So, now you are at a decision point. You have a questionable battery (is it ruined? can it be saved?) It is your choice to either continue down the path of trying to save the battery OR give up on it and get a replacement.  We dont know your exact budget an how much disposable income you have for this project, but just let up know and we will continue to assist you. 

 

The future - Once you have a useful battery the next step will be to put it in your car and start it up. Once running then we will be talking you through testing and proving your charging system. You will be using your voltmeter to do this. (as we promised buying it would not be a waste)

 

Again we don't know the exact condition of your charging system (generator, regulator and wiring) It was "worked on" but you were not sure if it was fixed properly. We want to help you test and prove what works and what doesn't, and then fix what doesn't. 

 

Then, when your battery and charging system is proven and reliable you can begin enjoying your car and go on to the next step in repairing whatever it needs. 

 

Let us know what is happening and what you want to do next. There are experienced people here that will help you.