Is my battery reversed??

30FordA50

30FordA50

Junior Member
Hello Model A experts,

I have been having all sorts of electrical difficulty and burned through a few alternators in the past year and a half. Both of my batteries are showing the same results as the pictures I attached. My charger may have been connected backwards (positive ground made me think I switch to black for ground and red became negative). I have since been told to keep them in order.

Did my trickle charger reverse the charge of my batteries? I have been tinkering with this multimeter and think I finally found the right mode.

Any experienced friends out there have any ideas?

Dennis
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Unlike modern day cars , Ford used positive ground on the electrical system. When you hook up your battery charger red goes to red and black to black. Do it directly to the battery, this way there is no confusion.
 
Man, it sure looks like your battery has the terminals reversed. I don't know if a reversed lead battery charger could cause that or not. I didn't think reversing the battery charger leads could reverse the polarity of a battery. I am not a battery expert. but what you have is really strange. It appears the battery or the meter has a problem. The leads and terminals for your meter appear correct. Did you try another meter to make sure the meter was made properly. Maybe you have used the meter before on DC and it reads correctly, polarity wise, which would eliminate the meter as the problem and point to the battery. You could test the meter on your modern 12V car battery. Let us know what you find.
Rusty Nelson
 
Is your car positive ground still?

Is the alternator made for a 6V positive ground system?

Any other modifications to the electrical system?
 
wrndln said:
Man, it sure looks like your battery has the terminals reversed. I don't know if a reversed lead battery charger could cause that or not. I didn't think reversing the battery charger leads could reverse the polarity of a battery. I am not a battery expert. but what you have is really strange. It appears the battery or the meter has a problem. The leads and terminals for your meter appear correct. Did you try another meter to make sure the meter was made properly. Maybe you have used the meter before on DC and it reads correctly, polarity wise, which would eliminate the meter as the problem and point to the battery. You could test the meter on your modern 12V car battery. Let us know what you find.
Rusty Nelson
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Thanks Rusty, multimeter is brand new and hooking it up on my modern red/red and black/black shows a positive 12 and change volt reading

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You are using your meter correctly. It sure looks like your battery polarity got reversed. It is possible if it is hooked up to the charger incorrectly for a long time.
 
Voltmeter are not polarity sensitive,you can hook them up either way and show voltage.Your burning points and other funny issues can be found with that meter however,hook up the battery correctly and read voltage across the terminals,the read voltage grounding black on the transmission,if there is a big voltage drop you can fix it by running a ground strap from the battery to the transmission,providing a secure ground to the pwertrain...my 29 deviated 2 volts,with the additional strap it's a 1/10th drop
 
Just as an experiment, hook a light to the battery and completely drain the battery. Hook up your charger correctly and see what happens. You might have to put a light bulb in series with the charger so it sees some resistance. What do you have to lose.
 
If I remember you can only reverse a batteries polarity is by COMPLETELY discharging it then charge it in the other direction, this idiot knows this for a fact, most people who have connected a battery in reverse will see sparks and probably smoke, I have over the years found batteries with reversed polarity from new.
 
Once a car battery has been complete discharged, it will never be worth a hoot. Get a new battery. Double check that your amp meter reads to the positive on a fast idle and that the battery voltage is higher at a fast idle than when to car is off.
 
If your battery is still in warranty, exchange it.
Otherwise you can try to completely discharge it and charge it correctly, but the chance of it still being a good battery is very slim.
Also, if you do this, be sure it's outside and away from anything you don't want damaged by an exploding battery.

Apparently you connected the charger to a completely dead battery, or you should have seen some good sparks from connecting it with the wrong polarity.
 
I just noticed this thread. In the original post, Dennis said that he had burned through a few alternators this last year and a half. I am wondering if the battery was connected with positive going to ground, but since he has gone to an alternator I am wondering if the alternator is a positive ground alternator or a negative ground alternator. If, by chance, the alternator is set up to be a negative ground system and he is trying to charge a battery that is connected with its positive terminal to ground and negative to the alternator, I suppose that would explain the situation. Worse yet would be if the alternator was a 12 volt alternator and trying to reverse-charge a positive ground battery.

I would say that a trickle charger would take a while to fully reverse-charge a battery, but an alternator could do it in pretty short order.

Check the alternator to see if it is supposed to be positive ground or negative ground.
 
Magicbox51 said:
I just noticed this thread. In the original post, Dennis said that he had burned through a few alternators this last year and a half. I am wondering if the battery was connected with positive going to ground, but since he has gone to an alternator I am wondering if the alternator is a positive ground alternator or a negative ground alternator. If, by chance, the alternator is set up to be a negative ground system and he is trying to charge a battery that is connected with its positive terminal to ground and negative to the alternator, I suppose that would explain the situation. Worse yet would be if the alternator was a 12 volt alternator and trying to reverse-charge a positive ground battery.

I would say that a trickle charger would take a while to fully reverse-charge a battery, but an alternator could do it in pretty short order.

Check the alternator to see if it is supposed to be positive ground or negative ground.
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The alternator is a 6v positive ground. I bought a new one from Brattons this time hoping to be done with the issues.

Original 6v + ground blew a voltage regulator about a year and a half ago . The 1st mechanic who fixed it used wrong internal parts (12v) in repairing it...the second mechanic was surprised I didn't fry the system.

I got a nice used red top battery from a friend and when used with new alternator, fired right up and got me home. A few weeks later, fuse was blown in the garage (key left on). Since then I have been trying to get to the bottom of the matter. At one point I had both batteries linked in series to the trickle charger because I thought the redtop was dead...now they are both reversed it would seem.



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Sparky said:
You are using your meter correctly. It sure looks like your battery polarity got reversed. It is possible if it is hooked up to the charger incorrectly for a long time.
Click to expand...
Thanks Sparky...that is what I am thinking

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