Battery with Reverse Polarity

This is the place to get help with technical matters concerning your M151 jeep

Moderators: rickf, raymond, Mr. Recovery

User avatar
m3a1
Lt. General
Lt. General
Posts: 4027
Joined: August 7th, 2014, 6:36 pm

Battery with Reverse Polarity

Unread post by m3a1 » October 3rd, 2017, 1:59 pm

I've looked at some old posts but need to know more.

My MUTT hasn't been driven in about 7 days owing to rain. I sent out to the A2 today and with the switch on, got absolutely nothing. Connections were correct, and tight.

I checked the batteries individually. One showed very healthy and the other, when hooked up properly and as per normal, pegged the needle to the left. Whaaaat?

Out of curiosity, and since that needle was boinking to the left, I swapped my connections of the tester to the terminals (pos-neg, neg-pos) and the darned thing showed fully charged, Put it on a smart charger as I should and got a whole lot of nothing. Did the pos-neg, neg-pos swap and it's charging but showing a very LOW voltage straightaway...

Its polarity is definitely reversed.

WHAT THE!!!! From what I've read so far, this can happen but how is it happening to one when two batteries are involved?

Cheers,
TJ
Last edited by m3a1 on October 3rd, 2017, 4:24 pm, edited 1 time in total.

User avatar
rickf
General
General
Posts: 19738
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Battery with Reverse Polarity

Unread post by rickf » October 3rd, 2017, 3:05 pm

I just had a battery do the same thing, single battery that had sat a long time, several months. I have never seen them do that before and I have no explanation at all. Mine was in my CJ-7. Was yours an Interstate battery?
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

User avatar
m3a1
Lt. General
Lt. General
Posts: 4027
Joined: August 7th, 2014, 6:36 pm

Re: Battery with Reverse Polarity

Unread post by m3a1 » October 3rd, 2017, 4:23 pm

Mmmmm no. I'm thinking this is a result of those solar flares and electromagnetic radiation. :lol:

I wasn't running a matched set of batteries anyway, and both were old cast-offs. Apparently one finally lost its fluxy while sitting for seven days.

On the plus side, it did it in my driveway rather than somewhere else....which is a good thing.

$84 later I'm back in business. Now I have two 65 series stuffed in there. A bit close, to be sure, but they aren't gonna rattle around, I can tell you that!

Fil Bonica
Brigadier General
Brigadier General
Posts: 2607
Joined: December 9th, 2007, 10:49 am
Location: ~ Heaven ~

Re: Battery with Reverse Polarity

Unread post by Fil Bonica » October 3rd, 2017, 7:45 pm

Could it be that the two were not matched and the result was the less charged one was drained and then reversed polarity.

Just a thought.
Fil Bonica
K1ABW

User avatar
m3a1
Lt. General
Lt. General
Posts: 4027
Joined: August 7th, 2014, 6:36 pm

Re: Battery with Reverse Polarity

Unread post by m3a1 » October 4th, 2017, 10:47 am

Well, from what I've gathered off the internet, the whole thing always begins with a fully discharged battery and my truck was running like a champ when I parked it but had been a tiny bit sluggish on starting. So now we know what caused that. Despite the fact that the batteries weren't exactly the same they were very close in terms of Amperage, CCA and reserve. Full disclosure, the battery in question was given to me by a friend some time ago so I don't really know its history.

Here's an interesting article on the subject of batteries achieving reverse polarity -

https://www.batterystuff.com/blog/batte ... arity.html

It seems to me having the one battery mated to the other battery (such as we do in our trucks) would seem to "set" the polarity for the other even if it were wholly discharged and yes, my connections were 100% right and 100% clean. Either way, after installing a new battery I'm back in business and we'll chalk this up as just another weird tale from the automotive world.

User avatar
rickf
General
General
Posts: 19738
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Battery with Reverse Polarity

Unread post by rickf » October 4th, 2017, 5:34 pm

Halloween is coming. In a parallel battery setup if one is a bit lower than the other it will drag the good battery down because they are directly hooked together but in a series setup there is no direct connection, voltage wise, between the two batteries so that will not happen. As I said, I just had one do the same thing in a single setup and there is an old analog clock in there so there was a drain on it all the time. That means there should have been no way for it to reverse.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

User avatar
m3a1
Lt. General
Lt. General
Posts: 4027
Joined: August 7th, 2014, 6:36 pm

Re: Battery with Reverse Polarity

Unread post by m3a1 » October 4th, 2017, 8:37 pm

Halloween IS coming! I wish I had more energy to get off my behind and put the Halloween stuff up.

I've added this illustration so that any new guy might more easily relate to what we're talking about here.

Image

I guess with the one battery completely dead and with the batteries hooked up in series, when I turned the master switch on it only "flashed" the dead battery into a reverse polarity because ultimately, it tested very low (and reversed) and we do know that a battery that is completely uncharged CAN be charged backwards.

I'm not an electrical whiz kid but now it's kind of starting to make sense. As for your single battery reversing, Rick, there would have to be an alternative source of power to accomplish that. Something that stored energy somewhere in the system. Coil? Capacitor?

Of course it could be those pesky space aliens again! :lol:

User avatar
rickf
General
General
Posts: 19738
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Battery with Reverse Polarity

Unread post by rickf » October 4th, 2017, 8:42 pm

It was parked on the edge of that damn 28,000.00 septic system I had to put in, that was what did it! I actually tried to charge it reversed but it would not take a good charge. A friend of mine runs a Batteries Plus store and he has been very big in battery powered cars since their inception so he knows batteries, I am going to ask him what his thoughts are.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

User avatar
m3a1
Lt. General
Lt. General
Posts: 4027
Joined: August 7th, 2014, 6:36 pm

Re: Battery with Reverse Polarity

Unread post by m3a1 » October 4th, 2017, 8:57 pm

Terrific. Please, ask him what he thinks about my situation while you're at it! Speaking only for my system, I'm concerned that this might be an indication of a little electrical gremlin that has made his home in my truck.

Fil Bonica
Brigadier General
Brigadier General
Posts: 2607
Joined: December 9th, 2007, 10:49 am
Location: ~ Heaven ~

Re: Battery with Reverse Polarity

Unread post by Fil Bonica » October 4th, 2017, 9:36 pm

Sounds like an exorcism is in order!

Fil Bonica
K1ABW

User avatar
m3a1
Lt. General
Lt. General
Posts: 4027
Joined: August 7th, 2014, 6:36 pm

Re: Battery with Reverse Polarity

Unread post by m3a1 » October 16th, 2017, 1:12 pm

Ok, here we go AGAIN. When I last left my truck, I had replaced the battery with the reversed polarity with a new one.

I drove my truck once, parked it and returned to drive it later only to find that the starter gear wasn't engaging the flywheel (though I could hear the starter spinning.)

At that time, gauges showed nothing irregular.

Without actually looking at it (because there was no time), we chalked that up to a lubrication issue, rather than an electrical issue.

Owing to other, more pressing obligations I had to leave the truck unrepaired.

A week has gone by and I went out to see if the same starter problem was still happening. Power on - nuthin. Gauges didn't even budge.

I checked the batteries and AGAIN, I have one battery with reversed polarity (the old one) and the other new battery at 47%.

There is no indication of anything grounding in or around the battery box and whatever is happening appears to be happening while the master switch is off which would seem to limit this issue to starter and starter circuit.

Would anyone care to weigh in on this? Once again, only one battery is reversed. I'm stumped. Yes, I am going to pull the starter but haven't done that yet.

Thoughts?

Cheers,
TJ

Fil Bonica
Brigadier General
Brigadier General
Posts: 2607
Joined: December 9th, 2007, 10:49 am
Location: ~ Heaven ~

Re: Battery with Reverse Polarity

Unread post by Fil Bonica » October 16th, 2017, 2:07 pm

Several things come to mind.
1, Scrap the Jeep !
2, the more practical one would be to
inspect and repair the starter,driv
Replace the batteries as a pair.
When replaced check for any current drain.
Years ago had a recurring battery drain: come to find out there was a draing through the main light swifc

Fil Bonica
K1ABW

User avatar
m3a1
Lt. General
Lt. General
Posts: 4027
Joined: August 7th, 2014, 6:36 pm

Re: Battery with Reverse Polarity

Unread post by m3a1 » October 16th, 2017, 3:02 pm

Well, I'm absolutely going to have to replace that battery so it will have a perfect match/mate.

I'm really hoping someone will come forward who has had a similar experience, and yes, the "scrap the MUTT" option is still on the table. :evil:

Hambone
Brigadier General
Brigadier General
Posts: 2495
Joined: October 1st, 2010, 12:19 am
Location: El Dorado, Arkansas

Re: Battery with Reverse Polarity

Unread post by Hambone » October 16th, 2017, 4:34 pm

If you think you have a short, get a multimeter that measures DC amps, unhook your neg. battery cable, put meter between neg battery post and neg cable, should be a little amp draw, start unplugging a few main suspicious things( main light switch, alternator, starter switch....) until you lose amp draw.

User avatar
rickf
General
General
Posts: 19738
Joined: November 26th, 2007, 1:28 pm
Location: Pemberton, NJ.

Re: Battery with Reverse Polarity

Unread post by rickf » October 16th, 2017, 5:19 pm

These alternators have a capacitor that will always show as a draw. It is not something that will cause that kind of problem though and it is in the milliamp range. Just so you know that when you see it.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Post Reply