Author Topic: neg to pos  (Read 7240 times)

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thirteen

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neg to pos
« on: February 20, 2014, 05:12:32 AM »
I have run across an odd battery problem. I was unable to get enough solar power to properly charge my batteries. I was only getting 20 minutes a day. I used my generator every other day to charge them up. I shut the solar off from Dec 18 , until last week and finally got enough solar sun to start charging them again. I just turned the solar breakers on and heard it start. I got 20 ft and it shut down. I checked things out and one of my batteries gave me an odd reading. I have two large batteries type D. this fall I will replace them with deep cycle batteries as my solar system will become much larger. My problem is that one of my batteries has switched neg to positive. They have not been moved or changed in any way. They worked fine for 7 months until I turned the solar off. ?? I think one of them has shorted inside. I used two different meters to check this out. It got my attention when I put my small gen set on to charge them. That is when I tested them.  I'l have to discharge the one and recharge it. They did have a charge in them when I shut things down. They are sheltered from the weather. They are hooked up fort a 24 volt system. The last battery is the one that reversed polarity. 13
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Flux

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Re: neg to pos
« Reply #1 on: February 20, 2014, 09:34:06 AM »
For this to happen there has to have been a circuit, it wouldn't have happened with nothing connected.

" I just turned the solar breakers on and heard it start. "  What does this mean, I have never heard a solar panel working. Do you have a tracker or something that could have been taking current.

My guess is that the batteries are going to be in a bad way and the weakest one has reversed charged from the better one.

Flux

HiddenMountain

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Re: neg to pos
« Reply #2 on: February 20, 2014, 02:59:48 PM »
Dang, I've never heard of this before.
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XeonPony

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Re: neg to pos
« Reply #3 on: February 20, 2014, 10:41:38 PM »
it happens, I  just built it up in the rever polarity and use it if it is a trash system, if not hand it in for the core and get new batteries.

More common in NiCads though cell reversal.
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HiddenMountain

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Re: neg to pos
« Reply #4 on: February 21, 2014, 02:48:30 PM »
Learned some thing new here today, thanks!
Energy Systems & Design Stream Engine, 30A @ 24V, 750W 
Magnasine MS4024P AE
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I hope they never find a cure for Eleutheromania

john8750

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Re: neg to pos
« Reply #5 on: February 21, 2014, 11:51:27 PM »
I don't understand how this could happen.
Keep the fun in it. Give me sun light.
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XeonPony

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Re: neg to pos
« Reply #6 on: February 22, 2014, 10:21:51 AM »
read up on batteries and how they are formed, basicaly the lead peroxide migrated to the neggitive plate as the other batteries opperated a sa charge source for the severaly low battyer when current was forced through it.

with care full recharging he can further form the neggitive plate into the possitive and use it like that till it goes totaly. I have don it to recondition batteries intentionaly as part of the desulfating process with distilled water
Ignorance is not bliss, You may not know there is a semie behind you but you'll still be a hood ornimant!

Nothing fails like prayer, Two hands clasped in work will achieve more in a minute then a billion will in a melenia in prayer. In other words go out and do some real good by helping!

thirteen

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Re: neg to pos
« Reply #7 on: February 24, 2014, 12:26:15 AM »
What I was referring to was the inverter trying to start. Magnum Energy Inverter RD 3924. 60 amp controler. all new. I've been gone for three days. I'll go over it again tomorrow. Something is not right ????
I do have a voltage guage in line to monitor things.
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Flux

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Re: neg to pos
« Reply #8 on: February 24, 2014, 03:47:45 AM »
If you measured the reverse voltage with a load ( inverter) on then you probaby have one cell gone open circuit. Unless it is a type of battery where you can measure individual cells then it is tricky to really know what is happening .

If you measure battery voltage with no charging or load then if that is the case things may look normal with perhaps one battery being low.

With load on the open cell will start to gas violently if you take much load. This seems much more likely than reverse charging, whick can't happen with the batteries on open circuit.

Flux

thirteen

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Re: neg to pos
« Reply #9 on: February 24, 2014, 08:53:57 PM »
I took the battery and tested it. 11.4 volts. It registers + pos on the neg post. the other battery only reads 9.8 volts and I am charging it tonight with my small genset. I'm not sure what I should do? Discharge it and recharge it correctly or try and use it the way it is. Magic smoke may invade my power shed. I also looked at the date and it is passed warranty by 42 days. I've never discharged a battery to correct the polarity. Any suggestions?  I have an old battery that I'll put in it's place tomorrow and check out my system to see if things work. 13
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thirteen

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Re: neg to pos
« Reply #10 on: February 25, 2014, 04:59:36 PM »
I hooked up my old battery (11yr) Everything started working correctly. 34v in but only 17 in the batteries.  I'll let it charge for awhile and go check it again. I'm going to borrow my neighbors  multi meter and check it against mine because something just doesn't seem right.  13
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Flux

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Re: neg to pos
« Reply #11 on: February 25, 2014, 05:09:13 PM »
Difficult decision. If the battery that measures 9.8v has dropped a cell the rest of it may be fairly well up, otherwise it is very flat. Either way it may be more of a problem than the reversed one.

I think reversing a battery once is fairly traumatic and it may be better to try to use it reversed rather than risk the discharge and reversal process. Probably much depends on luck but it may be ok. I once saw a pair of starter batteries on a big diesel generator that had somehow been reversed and they continued to start that engine for several years.

Probably the main thing is to find out what went wrong to avoid a repeat. I hope it works out .

Flux

thirteen

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Re: neg to pos
« Reply #12 on: February 26, 2014, 10:24:38 PM »
Tomorrow I will try and hook up the battery the way it is reversed. We'll see what happens. If it works I'll run it until it dies. or watch it take the other battery out with it. If I can capture the magic smoke could I sell it on e-bay. They sell everything else. I cannot see it working for very long. I'll find out tomorrow. Just so it gets me by until Oct.   13
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Frank S

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Re: neg to pos
« Reply #13 on: February 27, 2014, 12:53:05 AM »
Have you tried to bring the reversed battery back to correct polarity?
 back in the day of 6 volt cars it was not unheard of for a mechanic install the generator wrong, particularly when some were positive ground and the next year model was negative ground. When this happened the practice was to discharge the battery until flat using  the head lights then slow charge it back the correct way.
 I don't know about  the ability of doing this with modern batteries but it might be better than leaving it reversed 
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Flux

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Re: neg to pos
« Reply #14 on: February 27, 2014, 04:05:04 AM »
Can we check that I have not misunderstood what you have.

From your description I thought you had two 12v batteries connected in series for 24v and they have been left disconnected for the winter. If so there is no way for one to become reversed. If there are other strings in parallel or there has been a circuit through something then it can happen.

The main concern I have is the battery that reads under 10v. This almost certainly has a shorted cell and is the problem and it will not recover. You may be able to get it up to over 12v on charge but only by bringing the good cells up to gassing volts.

The reversed one seems to be ok and has all cells good. You can discharge it and re charge with correct polarity ( do it quickly and don't let it stand in the discharged state or it will sulphate in hours) or you can leave it reversed. Depending on its age I am not sure which option will give the best long term result. The plates are identical except that it is standard practice to have negative plates on the outside of the stack. If you leave it reversed you have positives on the outside and I suspect the outside surfaces will sulphate in the long term.

Every discharge to zero is drastic and reduces life, depending on the life left now you have to decide which is the worst option. If it is only just out of warranty you may have enough life left to try reversing but as the other seems to have dropped a cell I suspect these are near end of life and reversing may be not the best option .

If I have misunderstood what you have then please let me know.

Flux

thirteen

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Re: neg to pos
« Reply #15 on: April 16, 2014, 01:17:13 AM »
I've been going for awhile from here. I hooked up my reversed battery. It is running fine. I get 13.8 v out of it and it has been sitting for a long time. I will have my charger up here next week and will try to discharge it and recharge it correctly. I'll use my gen set and charger to charge it up. I'll put it on charge for 8 hrs then let it sit for 2 and if it checks out ok I'll fill my gen set up and charge it all night then put it back on line. I'll use the old backup battery during the charging.  She is 11 yrs old but still gives 12.8 v steady since getting charged fully.. It has been used and abused. I normally only use it for my RV pump for water every couple of  days. 
 
The only other thing connected was the temp censer for the battery. 2 X 12v =24v
1 1/2 years old All I did was shut all the breakers off to the batteries and the inverter. 
It will be interesting. Just so she is all together for next winter and working.
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thirteen

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Re: neg to pos
« Reply #16 on: April 30, 2014, 10:06:50 PM »
I finally got time to try and salvage my battery. I discharged it with an RV pump then used a light to run it down to O. I checked it with a meter and had 12.3 volts when I first started to discharge the battery. It had been sitting idle for 10 days. It took 3.5 hrs to get it to zero. I hooked my battery charger 30 amp charger from NAPA. It kicked out 4-5 times but charged my battery up. I left it run for 1 day then let the battery sit for 4 hrs took readings and had 13.6 v at the stopping of the charging and then after 4 hrs it read 11.5 v  I put the battery on a trickle charger (4 amp) and let it charge it all day then tested it and had 13 when I stopped charging it. The next morning it read 12.8 v. Yesterday I started my generator and hooked up the big charger again and let  it run all day. I had to add water twice for it bubbled  sent fumes for almost 4 hrs. Since then has settled down as i had turned the charger down to slow charge. I stopped and checked the voltage and I have 14.5 volts. I'll let it sit and well see the voltage in the  morning. The acid inside the battery looks clouded tonight. I wonder if I should change it or let it stay that way. It might settle down to the bottom but I am not sure. ?? I do need to see if the battery will hold up so I'll check each cell in the morning and go from there. 13
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thirteen

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Re: neg to pos
« Reply #17 on: May 01, 2014, 06:00:37 PM »
Fux
My battery tested at 13.0 volts after sitting all night. Most of the cells tested all ok but the last one next to the positive post. about half dead and that is the end where most of the fumes and bubbling came from.  It is in my solar system now. I'll see how long it lasts it has to get me to this fall then I'll have my whole solar system in and then I'll get new batteries. Worth the try. There is a first for every thing. If it becomes dead I will break it open and see if I can find something wrong on the inside. So for now I'll keep my fingers crossed and ask the battery gods for 6 mo life from my backwards battery. 13
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