Is a fully discharged battery now junk?

[LittleBill21]

lot of people have mentioned the smart chargers can't charge dead batteries, and this used to be true, the noco's and the one i bought link below, can be forced to charge, to get the battery up enough for the charger to recognize it and continue charging it. I have done this on battery's with 3v's in them without issue

Amazon.com

 

[Thereisagod]

From what I understand, regular lead acid batteries used for starting an ICE are not ever SUPPOSED to be fully discharged - which is why engines are equipped with an alternator to replace the amount of power used to start the engine in the first place and keep the battery "topped up" while it's working. There is another type of lead acid battery called a "deep cycle" battery that is designed to be fully drained then recharged, drained and recharged without damaging the cells. These are often used in marine environments with trolling motors or to power electrical "devices" with no alternator till empty and then be fully recharged.

 

[MMC]

I totally agree with you. I am managing many batteries of a few solar only systems, and I worked all my live in International Telecomms where we have large banks of batteries to cover the starting time of generators (my background is Solid State Physic). In addition to what you said, I would add that the longer a battery stay in the discharged mode the greatest the damage, since the sulphation process deteriorates the battery capacity continuously during down times. Also, in cold weather a discharged battery will freeze and be destroyed.

Not all battery are build the same, and some will survive better than others (i.e. deep discharge, some AGM, and those with better build quality). You can bring back some batteries that don't accept charging by applying a small period of over current (100-200 amps), but the total capacity of the battery will never be 100%.

Lot of good information here and I can only add a couple of suggestions. A heavy equipment mechanic told me years ago not to let a battery go completely flat simply because it often will not really come back to "full" charge - usable, but not the same as it was. Discharge a new battery 3-5 times to "dead" and it's toast for practical purposes. Keeping a battery at 100% charge on farms is not always practical due to reduced usage in winter. I counted just the 12V batteries we have and lost count somewhere around 30... And, as noted here, they are much, much more expensive these days.

To keep batteries "up," I have used automatic trickle chargers for years (got some old Schumachers on a few tractors 20-25 years old). I believe I now have about 12 or more in use during the winter. I especially like the newer digital readouts on some - I can walk into the shop and instantly see charging and standing voltage on those. Point is, automatic maintainers can save you money and headaches on equipment - cheap insurance.

And, I'll second the NECO chargers - pricey, but seem worth it. And...I think... the desulfation mode works, but can't prove it.

Last suggestion, if you want a really good analysis of battery condition(s), you might buy a Midtronics (or clone) tester. Yes, I have load testers and old fashioned (but accurate) hydrometers - if you can get to the electrolyte... But, I kinda like the Midtronics solution.

 

[vargy10!]

I mistakenly fully discharged the battery in my MX 5100 Kubota. It was a replacement likely made by Interstate. The battery was so dead it even tripped the 50 amp main fuse and I didn't know it could do that.

Anyway, I've been slow charging that battery but I have the feeling it's no good after a full discharge like that. Anyone know about this?

Most all of todays battery chargers do not start charging until it sees some voltage in the batt. I have had to do this multiple times so here is what is needed. Take a second battery that has some voltage in it and hook both terminals to your dead battery. + to + and - to -. Then attach your charger to the dead battery (turn on) while leaving both batteries tied together. Leave everything attached for about an hour or two then unhook the second battery while leaving the charger attached to the what was the dead battery. You will find the dead battery has started taking a charge so leave attached until fully charged.

 

[Paul_M]

Discharged batteries start to oxidize the lead plates. Leaving batteries discharged for extended periods is definitely bad.

Single time and it was charged fairly quickly….may not be a certain death sentence.

The degradation process for discharged lead acid batteries is called "sulfation", the formation of lead sulfate, which effectively insulates the plates and can inhibit both charging and discharging. The process takes time, so a short period of discharge (below 11 volts for 12.6V batteries) doesn't hurt much. However, leaving a battery discharged for months definitely shortens its life and discharge capacity. There are desulfation "rejuvenation" chargers which blast the battery with short pulses and can cause the sulfation to flake off the plates. This works better for batteries that have ample space at the bottom of their cases to hold the sulfate particles. Once those recesses are full of sulfate, further rejuvenation results in case swelling and often shorting between plates.

 

[qualsite]

Usually not a problem unless a continued practice. Best to keep a battery maintainer on the battery. A good battery charger is always helpful, particularly one that will run through a desulfite regeneration mode. The grid will eventually build up with crystals, lowering the capacity of the battery, until it becomes worthless. Keeping a battery maintainer on it will keep the charge up and help slow the process down, but the regeneration mode on a charger will pulse higher voltage through the battery for 24 - 48 hrs to put the solids clogging the grid back into the battery acid, where it belongs. If it's really bad, you can draw off a bit of the battery acid from each cell, and replace it with epsom salt solution [magnesium sulfate], which also helps to regenerate a battery. That will usually keep a battery going long past the normal life, unless you lose an internal cell connection or other physical issue with the battery. Also, an AGM battery uses an advanced grid design and material [thus the AGM], and they are usually a bit more durable for a longer run.

 

[ArlyA]

All electronic schumacher chargers have a desulfation cycle built into them. I have several and they seem to work.

 

[MRTOES]

If it is not a sealed top get a "floating ball" tester. After charging it test each cell. You may have a shorted cell from flaking or plates moving. The flaking may be solved by rinsing the cell out with a solution of baking soda after draining the acid then refilling it.....I said maybe....
However you said you blew a 50 amp fuse. The battery didn't do that, a short somewhere else most likely did and at the same time may have warped the plates.

 

[POGuy]

I bought an old Farmall Cub at a silent auction at work last fall. It had sat unused for 17 years. The 6 volt battery in it was shot. They gave me a second, 18 year old 6 volt battery, along with it. The second battery had been purchased new, but never installed.

I had a very difficult time locating a new 6 volt battery, so I took the (6) year old one out of my Ford 8n, and put that on the cub.

I filled the (3) cells with distilled water (each took a cup or so) and placed the “spare” 18 year old battery on my 6 volt charger. I was able to start the 8n with it, the first time, even though it only showed 5 volts on a meter.
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The second time I had to jump it with the Cub. I then ran it hard for about (4) hours plowing a field, allowing the old Ford tractor’s generator to charge it fully.

Since then, Ive been using that old battery in the 8n all year, and it has started it good every time. Apparently, a 6-volt lead-acid battery can be left dead on a shelf and half dried up for quite a few years, and still be good.
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Glad to see you set the parking brake !

 

[buckeyefarmer]

My original kubota battery just died after 12 years. It would not charge at 8V. I did a short reconditioning on it, it then would start to charge, but it sounded like the battery was boiling so I stopped it. 12 years, i'll probably buy a new battery.