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Anyone here sharp on Lead Acid battery charging and desulfating?

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fastline

Member
I knew I needed to update my charger line up. I figured the technology for charging would be so main stream that manufacturers of digital chargers were getting it right. I bought bigger wheel cart model with digital automatic routines only to realize that I believe it is JUNK and will likely just ruin batteries. I tested on a start battery that was sitting at 12.3V. I used the automatic routine and found that after I believe the battery was mostly charged, the charger was cranking out 15.5V at 5A! It was going to boil that battery! It never did go into a float mode, and the instructions indicated it would "auto detect" FLA/AGM/GEL. I see no way that can happen! There is no switch for it. Long story short, I believe the charger is junk.

So I started both shopping again, and educating. From what I can tell, a reasonable charge rate for start batts might be about C5 but this is for Ah ratings. From research, it appears a reasonable approach to start batts is 10% of the CCA would be considered for the Ah so a 1000CCA batt might be charged as a 100Ah batt or C/5 which is 20A.

Now, sulfation will always be an issue and it seems that pulsing high voltage and current on the beginning of the charge is ideal for a desulfation routine? Maybe 15-16V for a 12V batt?

I am also not sure I understand how to determine a battery state of charge and when float should be employed? From reading, it appears float should be lower V and A for topping, but how can I determine where I am at? I am obviously looking for an automatic charger, but I like to monitor things to ensure things are right.

The battery I tested had a surface charge of 13.4V when I disconnected, and rolled back to 12.7V, where it is now. When I charge a batt, I typically look for 13.5-14.0V surface and I want to see it stay at 12.6-12.7V after surface charge wears off. However, I am not sure if that is accurate enough? It seems I may not be allowing float time, which can be considerable on big batts and maybe not topping my batteries to 100%?

Does anyone have any recommendations of REAL auto chargers that work? I have everything from small ATV GEL and AGM batts, up to big industrial batts.
 

tcmtech

Banned
Most Helpful Member
I for one have near zero trust in any automatic battery chargers either. :mad:
Good old fashioned dummy units (with digital gauge updates) is all I ever use and ever will being too many times I have seen a smart charger reject a good battery for the wrong reasons or just come up short on what it needed to do.

For me 'a reasonable rate of charge' is whatever the battery wants until it hits ~ 14 - 14.5 volts which for deeply discharged batteries may very well be whatever their C rating of cold cranking amp rating limit or the current capacity limit of the charger is after all most vehicle and mobile equipment batteries are recharged by alternators that may have some pretty serious reserve amp capacity in certain running conditions. For example, most of our old tractors have been refitted to modern alternators of which most are 70 - 100+ amp units that in normal running conditions draw 1 - 2 amps (or nothing for the magneto ignition tractors) for the simple ignition system they have. That leaves a whole lot of spare amperage available to charge a run down battery at times. ;)

For desulfating I have a old battery charger I redesigned to give about 15 volts at a .5 amp load (~17 VDC no load) that works very well for desulfating. I just let the battery sit and hard charge and cook for a day to several days with it and either the battery gains some working life back or it doesn't. Some old riding lawn mower batteries have sat and several amps for more than two days before getting to 15+ volts and dropping back to the .5 amp or less rate. Or they were junk due to damaged cells and became core exchange units for new batteries.

My general rule is any LA based battery, that is not junk, can handle a good hard 15 - 15.5 volt charge for some time (day and longer) while desulfating even if it means they have to out gas and heat up a bit while doing it which means letting them draw several to 10 + amps while they run the process. In many engine compartments they sit in temperatures exceeding a 150 F for hours on end and still last for years without issue so getting warm to the touch, 90 - 110 F, during hard charging isn't really hurting them.

As for end charge voltage I consider any battery that holds ~ 12.5 VDC or higher 24 - 48 hours after being hard charged for a day or more good. If it's below that and keeps dropping over the next few days or week I figure it's at the end of its life and goes into a no critical application (low seasonal use machinery) or the core exchange pile.
 

fastline

Member
hmm, I certainly need to optimize my procedures as I tend to "set it and forget it", with a 6A analog charger, and check on it later. However, I think some of my process changed when I think I boiled off a battery in a truck by leaving the charger on it for 2days. The 6A charger, though slow, rolls back on amperage and I know that battery was not taking more than 2A. Could have been a junk batt.

My biggest concern, and seems to be the main common concern in charging, is boiling off the batteries. Seems you may want some bubbles which means you are converting crystals back to useful electrolyte if I have that right, but too much current will boil them off? Maybe batt temp is really the best means?

I know I have pulled a cap on batteries and realized they were really churning! I am not sure how much is appropriate?


TCM, I am curious, if you leave a 15V/.5A charge on a battery for days, will that not end up just fully charging the battery?

Then there is the float thing. Some reading indicates this needs done or your battery is not fully charged. Then others refer to this as a "maint charge" only to sustain the battery and can be put to use otherwise. I see lots of reading that talk it up about the "perfect charge", but even if you hit that magical 100.0001% charge, that is going to the crapper as soon as you use it! Then there is self discharge anyway, so at some point, you gotta go with it.

Part of my reason to explore chargers and charging is I indeed have some big multi battery equipment, one is a pair in series, another pair in parallel. I ALWAYS get nervous with batteries in parallel because if one takes a dump, the others will follow. My series connected excavator had a bad fall, I left the master switch on!!!! I wanted to beat myself BUT, I got them to take charge. However, one is being stubborn and wants to roll back to 12.2V, in which I cannot tell if it still needs charge or if it has a problem.

My tractor is parallel and even letting it run for 2hrs and charging at 10A or more, The voltage rolls back from 12.6 to 12.1. I know these batteries MUST stay charged or sulfation is happening so I like to stay on top of this.

Anymore, in the winter, I have a PILE of batteries that all come out of machines and put in the shop and I check and charge as needed. I am ready to get small pulse chargers to lighten my load!
 

tcmtech

Banned
Most Helpful Member
TCM, I am curious, if you leave a 15V/.5A charge on a battery for days, will that not end up just fully charging the battery?
It gives them a full charge plus I find it's also producing just enough overcharge most times to be able break down the sulfation in most still functional batteries without cooking them to death in any reasonable time frame.

The problem I have with the battery snobs and their numbers (that likely go into smart charger programing) is they are typically idealistic and quite far from the working ranges of reality. :(

I see people on forums post that such and such battery chemistry or design has to have exactly XX.xxx voltage at whatever charging stage which in reality is rarely right being there are a number of other factors in a battery's design and immediate set of conditions that can put all of those numbers way off.

For example, just temperature alone can push the ideal charge voltage points +-10% or more from the ideal value. Same with the actual battery internal components chemical compositions plus state of condition. Add all that together and now their ideal value of XX.xxx is that +- 10 - 15+% which means that depending on the age condition and temperature that 14.4 ideal bulk charge voltage is actually anywhere from low 13's to around 16 volts and a proper full standing unused charge is anywhere from 11-ish to 13-ish volts. Pretty vague numbers when stating voltages to 100ths of a volt in ideal conditions.

Then there's the real world problem of sometimes a battery physically came apart inside and no matter what is done to it it wont fix it to which too many associate the failure to recover with it having over/under charged it and killed that way when in fact they did nothing.

Also there's the timeline behind things like sulfation build up. It doesn't happen overnight if a battery sat at a less than ideal charge state. Even in a stone dead battery it can take weeks and often more to build up bad enough to be a problem. I've had many batteries that sat outside dead all winter that still came back to life well enough to work in near daily usage for a year or longer after one long day, or a few, of hard charging. Sure they weren't as new capable 100% but they're still well above the point of doing what I needed them for day in and day out.

Lastly, I look at it as a battery is a manufactured consumable and they go bad for way too many variables I have far better things to worry about than them. If I can keep them in equipment where they see anything close to the proper range of charging voltages and usage 2 - 3 times or more a year they are good enough. If not, and I remember, a night or so on the charger is still good enough. :)

Then there is the float thing. Some reading indicates this needs done or your battery is not fully charged. Then others refer to this as a "maint charge" only to sustain the battery and can be put to use otherwise. I see lots of reading that talk it up about the "perfect charge", but even if you hit that magical 100.0001% charge, that is going to the crapper as soon as you use it! Then there is self discharge anyway, so at some point, you gotta go with it.
Just for an idea of what my one 'fancy digital charger' is, it's just a old 15 amp cheapo unit that I modified a bit. I added a 20, 30,000 uf 40 volt capacitor just after the main rectifiers then fed that through a a pair of large diodes to get a ~ 1.4 volt voltage drop to bring the peak open circuit voltage off the first capacitor down from ~ 19 volts (way too high) to around 16.5 - 16.8 VDC then put a second smaller 3000 - 4000 uf capacitor after that. I have the digital voltage meter reading that voltage with the current shunt for the amp meter on the negative return line. The two step capacitor filtering give the digital meter a more low ripple DC to work with which makes it far more accurate on what voltage the battery is actually getting.
With the high ripple unfiltered DC the peak wave forms can be 19+ volts and the meter never saw it resulting in false voltage to current readings where it was forcing a battery to take a multi amp charge even though digital meter said it was still at only around 14 volts when it was really pushing 16+ which is why the two diodes and second smaller capacitor had to be added. :(


As said before at about half an amp load it sits pretty stable at ~ 15 -15.5 volts which so far has never bothered any battery regardless of size even after sitting for several days at that voltage.
I've tested it with a few old riding lawn mower batteries for long term charging, 4 - 5 days, and surprisingly so far every one that was still good enough to come back to life at some point leveled off to near zero amps charge rate at around 15.5 volts give or take. THe ones that didn't just sat at the 16+ voltage and no amps reading points and did nothing.
 

fastline

Member
Hmm, you mention a really good point regarding Dc voltage vs ripple. I will now drag out my good meter and look at this.

In my testing today, I decided to kick up that known good start batt and let that China junk charger chew on it a bit more. I pulled a cell cap just so I could monitor the electrolyte boilage. That batt stayed at 15.5V and 2.5A for hours..... I did not detect any serious boiling, just occasional bubbles (normal). I finally disconnected it as it was obvious the charger was not going to ever float and would probably just boil the battery off. How do I know? The charger indicates the charge is complete and at 100% charge, yet just keeps pumping charge...

Two questions I have at the moment

1. Can it be generally accepted that if a battery holds a charge at 12.6-12.7V, it is considered charged?
2. What is the best plan for desulfation? This seems all over the map from "not a good idea, could damage batt", to "the best thing since sliced cheese".
3. Regarding desulfation, are there several ways to skin this? Seems there is med V pushing (16-18V), high voltage pulsing (60V), and std V/high freq. I am sure everyone feels theirs is better, leaving me wondering how they quantify that and if all methods likely work about the same?
 

fastline

Member
Well, found some interesting stuff.

1. Both the new China charger and my old 6A analog charger throw out about 15-20mA of ripple, hovering around 120hz. Seems reasonable?
2. More interesting, my little 6A charger, when thrown on my VERY charged battery was actually charging at nearly the exact same as the new "digital hotness" charger, 15.5V/2A. No doubt if that were left for days like that, I would boil a battery.


What is very odd to me with all the "state of the art" chargers, is it would only a take a VERY simple key stroke to even further optimize a charge routine, its called TEMPERATURE! I mean, you don't even need to really monitor the temp, just inputting the actual or close enough batt temp could really help! I read where one charger was "the best" because it had a built in TC onboard. I laughed because who knows if that charger is the same temp as the battery.

Anyway.
 

tcmtech

Banned
Most Helpful Member
Hmm, you mention a really good point regarding Dc voltage vs ripple. I will now drag out my good meter and look at this.

Two questions I have at the moment

1. Can it be generally accepted that if a battery holds a charge at 12.6-12.7V, it is considered charged?
2. What is the best plan for desulfation? This seems all over the map from "not a good idea, could damage batt", to "the best thing since sliced cheese".
3. Regarding desulfation, are there several ways to skin this? Seems there is med V pushing (16-18V), high voltage pulsing (60V), and std V/high freq. I am sure everyone feels theirs is better, leaving me wondering how they quantify that and if all methods likely work about the same?
Yea I consider that voltage range sufficiently charged. Most of the time with a well used battery anything that's close to 12 or higher is good enough. I'm not fussy about ideal charge. just have enough to do what I need it to do charge.

No idea on best sulfation technique myself. I prefer the slow cook for a day or two at the ~ 15 - 16 volt level and see what comes of it. If nothing the battery is well beyond its working and trustworthy life and not worth messing with.

Years ago I built a constant current charger that could put out either 2 or 10 amps at up to ~ 160 volts to try and recover deeply sulfated batteries. It works to a point but no battery that I recovered ever proved to be reliable enough to trust for anything and I got at best 1 - 2 months of light use out of any before they were total junk.

A guy only has to get stuck 4 - 6 miles walk from home once because a thought to be goood recovered battery they put in a tractor decided to permanently end its life out there.
Same with trying to get a jumpstart in a store parking lot because an assumed recovered battery gave up there. Or a stoplight because one went out and shut the vehicle down at that point and so on.

Been there done that and largely gained nothing for the inconveniences had over what little bit of extra (and highly unreliable ) battery life desulfating got me. Now when a battery gets weak in a critical high use application it gets pulled and and new one goes in. Then that weak battery gets a good hard charge for a day or two and put in a lower use non critical application until it's too unreliable there. After that it becomes a core exchange unit for a new battery.

Yesterday I spent ~ $265 and bought a brand new pair of group 65 batteries which went in my pickup and flatbed trucks which are high use critical need vehicle applications so that their still good but not new batteries could be repurposed to a pair of tractors for the next few years that just need batteries that are good enough to get them to start. Sure the new batteries could have went in the tractors but I prefer to put the newest ones in the high use stuff and move their old ones to the lesser used equipment. Seems to prevent a lot of issues where they count most that way. ;)
 

fastline

Member
Hmm, Cannot say I have really been stranded by a battery yet but nothing seems to piss me of more than getting in equipment, then having to jump them....So I try to monitor things. It becomes quite a job!!!! Thus why I was wanting automatic chargers I could trust, throw on, and ignore. Nope....

We have a battery tester here too so I tend to throw a hard pull on stuff and make sure they can do something. One thing I know for sure is my excavator needs 2 good batts and they are in series, and this becomes a huge problem if those batts are down. It only has to roll over once and lights, but takes some juice!

Now my truck batt I have been babying along and it might actually bite me but I know it is getting close. I know she turns over a touch slower than it used to AND I actually lost it totally a year ago because apparently the negative bar inside the battery is gondy! Took me a minute to solve this. Truck ran an hour before, get in truck, nothing! Knew that was looking like a batt issue. Checked voltage on batt, 12.7V!!! WTF???? try truck again, nothing. Then noticed heat building up seriously on the Neg term. Figured maybe it was dirty. Cleaned, still no good. Then I clamped up on the top posts of the batt so I could see it drop. NOPE, stayed around 12.7.... Getting puzzled, I then figured out the heat was telling me what I needed. Too much juice through a small straw..... BUT, the top posts that I paid extra for, were still good! So I just fabbed an adapter for the NEG annd figured I would ride it until dead, then remove adapter when I sway batt.

So, I was thinking I would make it through summer but now not so sure. Am I worried? Not really.....since I seem to go down to the farm with a bed full of batteries anyway!!!!:D
 

dr pepper

Well-Known Member
Most Helpful Member
I've had industrial plant machine batteries do something similar, they charge at 14v with a couple of amps engine running, and read over 12v after stationary for 1/2 hour, then when you press start the voltage drops to 1v or less.
Some say thats a surface charge, however I dont think that is the case if the battery goes from everything ok to will not crank the engine, something inside has gone clonk, probably one of the bonds onto the plates making that cell and therefore the whole battery high resistance, causing the above.
You can usually tell a battery thats about to give up, put a straight edge on all sides, if one or more is bulging then its on its way get a new one.

There is some conjecture on desulphators, some swear by them, some say they dont do anything, my opinion is that if your battery gets to the stage where it wont crank the motor its had it, a desulphator might lengthen the life however I'm not so sure if it would bring back a mutilated cell.
 

eKretz

New Member
Sometimes desulfators work, sometimes they don't. I think it's basically dependent on how far gone the battery is and for how long it's been that way. The longer a battery is sulfated, the harder it is to bring back. The best possible solution is to keep them from getting sulfated in the first place.

I've got a 4-bank auto charger made by Battery Tender that works awesome. I normally get almost 10 years out of the lead acid batteries in the stuff in my garage - I keep a motorcycle, a quad and a lawn tractor on mine at all times when they're not in use. All have been kept on the charger for over 10 years and all have had one battery replacement.

I tried one of the eBay desulfators on a failed car battery (rated 650CCA) and it actually seemed to make the problem worse! I used an old Sun (carbon pile) battery load tester to check voltage drop under load before I started playing with it after a fresh charge, then progressively as I tried the different desulfating tricks - at the beginning the battery could put out about 150 amps but was dropping down under 6VDC. By the end the battery couldn't even supply 100 amps and was dropping down nearer to 4VDC. That one was just too far gone I guess.

The one thing I didn't try was removing all the acid and replacing with water then running a high voltage charge. This is supposed to make it easier for the sulfate to dissolve into the water since it doesn't saturate like the acid. You're supposed to keep charging until the specific gravity of the water stops climbing, then remove the water and replace it, charge again etc. until the specific gravity doesn't climb with fresh water anymore, then drain the water and add fresh new acid.
 

MikeMl

Well-Known Member
Most Helpful Member
I did some testing when pulse-type de-sulphator circuits first appeared on the Web about 15 years ago. I concluded that they are slightly effective, but that their benefit comes from the same principle as "equalizing" flooded-cell lead-acid batteries. In other words, if a mid-life battery might benefit from an "equalization" charge, then a pulser does the same thing, but just takes weeks to do what an "equalization" charge can do in a few hours.

An equalization charge happens when you connect a constant-current supply to the battery for a few hours. The pulser is nothing but a constant-current source for the duration it takes to discharge the damn inductor. All of the "crystal resonance" stuff is pure b.s.

I typically use my lab supplyto equalize a battery: I set the open-circuit voltage to about double the nominal battery voltage (24V for a 12V battery, so the supply never voltage limits), and set the short-circuit current to 3A for a mid-size cranking battery (so that the battery seeks its own voltage).

Remove the battery from the vehicle while equalizing. The battery voltage will climb initially, plateau, and then begin to drop slightly. During an equalization charge, a typical 12V starting battery will climb to ~16.5V, and I stop equalizing when I see it drop back down ~200mV below whatever it peaked at. Never leave the current source connected longer than about 4 hours after it reached its peak voltage.

Be prepared to add distilled water to the cells during equalization (never let the tops of the plates get exposed). A hydrometer (in lieu of the voltage drop) can also be used to determine when to quit equalizing. Quit when the S.G. of the last cell stops climbing...

Read this to learn about equalizing flooded-cell batteries. I do this routinely (about twice a year) to starting/storage batteries in little-driven vehicles, airplanes, boat, golf cart and my RV. I routinely double the service life of the battery compared to never equalizing it...
 
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chemelec

Well-Known Member
The First Problem is to determine if the battery is Really Sulfated or just OLD with a bad cell and Needs Replacing.
Sulfated batteries are mostly the result of being left in an Under Charged state for long periods of time.
Not a usual thing to happen for a car battery as it is being used and charged mostly everyday.
But common for equipment that is only used in the summer, but than left unused all winter, like Farm Tractors or RV's.

I have Salvaged a Few Batteries with my de-sulphator, that I use for Occasional Use in my shop.
Don't always remember to Charge them regularly.
They Never get back to Original New Condition, But at least Much More Useable.
 

MikeMl

Well-Known Member
Most Helpful Member
...
Sulfated batteries are mostly the result of being left in an Under Charged state for long periods of time.
Not a usual thing to happen for a car battery as it is being used and charged mostly everyday.
But common for equipment that is only used in the summer, but than left unused all winter, like Farm Tractors or RV's...
Here in Arizona, unused batteries sulfate because they self-discharge in hot weather (at 100degF, they lose about 15% of their total charge each month even if completely isolated from parasitic discharge loads). To minimize sulfation while resting unused, preventing being less than about 90% fully-charged, it is necessary to use "float charging". Note that a proper float charger must be very-well voltage-regulated (+-1%), compensated for ambient temperature, and set to match the battery chemistry (ideal float voltage is different for pure lead plates, plates with Calcium, and AGM sealed batteries).

Another problem is that flooded stationary batteries (ones that do not get sloshed by vehicle motion) stratify, meaning that the acid sinks to the bottom and leaves less dense electrolyte at the top. This causes the plates to sulfate at the top, even if the battery appears fully-charged. One benefit of equalization is that due to bubble formation at the bottom, the bubbles rise, mixing the electrolyte to make the S.G. more uniform from bottom to top.
 
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chemelec

Well-Known Member
All Lead Acid Batteries Self Discharge, Even the ones in my normal Room Temperature shop.
So isn't your batteries losing 15% of there charge each Month, Resulting in Being left Undercharged?
 

MikeMl

Well-Known Member
Most Helpful Member
All Lead Acid Batteries Self Discharge, Even the ones in my normal Room Temperature shop.
So isn't your batteries losing 15% of there charge each Month, Resulting in Being left Undercharged?
No, because I keep a float charger on them. The float charger prevents self-discharge, but does not prevent the electrolyte from stratifying, hence the need for both floating, and periodically equalizing little-used batteries...
 

MikeMl

Well-Known Member
Most Helpful Member
I have built many 12V lead-acid battery maintainers over the years (an interest of mine). The ones that seem to do the best job use the following algorithm:

First, the charger is intrinsically current-limited to protect the charger if connected to a totally discharged or shorted battery. The max current, or ripple content, doesn't matter much, but for automotive starting batteries, a couple of Amps is fine...

Second, the charger turns on when connected to a battery whose terminal voltage is less than ~12.8V (cutin). The charger puts out its max current (~2A, acts like a current-source) until the battery terminal voltage reaches 14.5V, at which point it turns off (cutoff). There is a LED on the charger to show when it is charging; off while resting.

Third, the charger's voltage sensing circuit has a high input impedance (>~100kΩ), so the load on the battery while the charger is resting is minimal.

Discussion:

If you connect a badly discharged battery to the charger, you can expect the charge LED to stay on for up to 3o hours initially, and then begin cycling as described below.

It normally takes about half a day for the surface charge voltage of a healthy battery to drop from 14.5V to below 12.8V. If you see the off period get below a few tens of minutes, you need to take a close look at the battery. It may have a shorted cell, or be on its last legs... There may also be a parasitic load connected across the battery, causing the battery's surface charge to dissipate quickly.

If the charger can never shut off, you certainly have a shorted cell.

A healthy battery will settle down to a short on/long off duty cycle, like 5 min on to several hours off. If you see a battery that oscillates from on to off rapidly ( a period of a couple of minutes), it has developed a high internal resistance and needs to be re-cycled...

During the charging phase, the cutout voltage reached by the battery just as the charger shuts off is close to the voltage regulator setting in modern cars. Left isolated, a fully-charged starting battery will stabilize at around 12.65V after all the surface charge dissipates several hours after being disconnected from the charger.

The cutin voltage of ~12.8V is not much above what the final resting voltage would eventually be.

This charging algorithm sort of emulates what happens if the battery is in a car that is started and driven to work every day. Since the battery spends some time per day at >14V, it tends to stratify less than one that is held at a constant float voltage, like 13.2V... The parasitic load in the typical modern car pulls the battery voltage down to ~12.7V soon after the car is parked.

Guess what? This charging algorithm can be implemented easily with a 555 timer used as a window comparator and a voltage reference chip to regulate the cutin/cutout voltages. You can think of the battery maintainer as an oscillator, where the characteristis of the battery itself determine the oscillator frequency/duty cycle...
 
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ci139

Active Member
-- not trying to hijack the thread nor start a new 1 on the subject as i guess it fits inside here --
basically i have some 10yo(years old) 12V 70Ah 640A (with a nearest matching datasheet i could find , or attached)
that still 5 month ago dropped to 12.82V after charging and didn't drop below 12.66V for days
but now ??? has starting to die -- as i just tested -- the procedure ►►
  1. 12+ h at apx. 2.6A
  2. 6+ h -- mixed 1A up to (likely over spec.-d →) 17.5A (due dropped internal EMF) -- the terminal vtg. didn't rise over 15.8V
    i speculatively chose the best fit amperage as the highest rate not to inc. the batt temp. and keep it from bubbling too heavy (spitting out the liquid "spray")
  3. apx. @ +44°C , r = 88.494mΩ , ε = 10.741V -- measured immediately after it seemed the batt. won't accept any more charge (kept dropping back to a very same const. voltage level)
  4. ~ 1h -- as ↑2.↑
  5. apx. @ +22°C , r = 86.143mΩ , ε = 10.232V -- measured 24h after ↑4.↑
the curious thing here is that the SOIC shows neatly green ???
-- the reson most likely is soic being located in the 2-nd cell but the 6-th cell had it's plates out of electrolyte :confused: the battery is supposed to be a "maintanance free" and they had a sticker covering the inlets of cells 5 to 6 - so i never checked them ((((monkeyf-s ... about trusting an idiot - the producer - of this bulls - 's FIAMM . . . . . . . . . basicalli it performed too good too long so i got used to such - should've been accounted it getting older obviously requires more care !!))))

Further links i found interesting/practical for my personal study
 

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Mosaic

Well-Known Member
I have a couple thousand hours of Engineering R&D and prod. dev logged in this area. Battery regeneration (of failed batteries) as opposed to preventative maintenance.
MikeML is largely correct for 'normal' batteries, so I won't restate his comments.

But I do have an advanced solution capable of regenerating batteries and even identifying single cell fault conditions while rerating the battery on the fly.

For apparently defective/abused batteries the charge profile executed by automatic chargers is out the window. There is no charge profile that fits the bill exactly as a battery can have any number of problems, sulphation, dendritic soft shorts, buss bar corrosion, plate shedding, hard shorts, electrolyte contamination etc. etc.

I quantify regeneration as > 40% OEM Ah and > 80% OEM CCA, as the battery can be put back into OEM service or alternative service based on known ratings. I have run tracer studies on car, truck & marine batteries deployed back into OEM service with a 3 to 6 month tracer window. My own batteries have had a 3 year window as they are easily traceable ( 4 vehicles). A couple hundred batteries in all.

The regeneration is fully automated and quantified for all 6& 12V lead acid batteries EXCEPTING GEL . I have not encountered a single defective GEL battery from auto/marine sources, so either they really last long or aren't used much anymore except in cell towers.

So, how does this help the OP?

It depends on his needs, I am about to finalize production of the WiFi IoT enabled battery rejuvenators which offer remote control and monitoring with datalogging and results yield traceability. These units are built for 24/7 service and can sequence & hotswap 2 batteries for continuous regeneration or boost charging or rerating or any combo of those.

Typically a discharged 70Ah auto batt will regenerate in less than a day if it has been discharged < 3 months, a 6 month discharged batt might take a full day etc. Early rejection for critical battery failures takes place to optimize system use. Only batteries which pass the rigourous pretesting (automated) will be regenerated.
There are AV alerts , an LCD display , intrinsic battery protections (Voltage, Hall effect current & temperature), multiple internal dignostics and dual processor operation with two additional float charge connections for completed battery regenerations.
Electronic fusing, foldback limiting, temperature monitoring of power distribution interconnects & enclosure ambient plus crowbar fusing ensure failsafe ops.
Kelvin measurement system with 0.1 milliohm precision battery impedance measurements.
The output cabling uses 4 x 14 AWG OFC cables per clamp for reduced impedance and better power distribution.
4 button interface.

I am looking at creating a unit targeting individuals with reasonable access to batteries, small fleets or who prefer a quality tool (not Asian...although my Asian ancestors came over 150 years ago) to have on hand that regenerates and rerates lead acid batteries.

It will incorporate the same tech from the 'industrial' unit , but won't sequence/hotswap or do 6V batts. It will run at 5A max RMS and be more compact and use certified components and quality interconnects. No cladded wiring , only 99.9% soft copper and 200A RMS rated clamps with real bite.

Here's a pic of the protoype processing 2 batteries. The pic. contrast makes the LCD text invisble though.

Regen.jpg

The bright glow inside is an incandescent lamp dissipating about 20W of backemf energy as occurs when a battery is doing well.
 

dr pepper

Well-Known Member
Most Helpful Member
Very interesting mosaic.
Could you briefly explain plate shedding, thats one I'm new on.
I too have been working with internet enabled devices, very interesting, but I keep away from iot, I like to play with device to device or browser to device.
 

Mosaic

Well-Known Member
Plate shedding is a 'normal' ageing process when the battery is cycled. Starter batteries have plates formed of lead and leady oxides composed of finely divided lead oxide blended in with expanders to permit a porous paste to be formed on a lead grid structure to make a 'plate' after pressing and drying. these plates are stacked to make a battery cell, eg. a 9, 11 or 13 plate battery is reflective of increasing battery power output.

Such plates can be made fairly thin to improve CCA output at the expense of battery longevity. Longevity loss occurs as the pasted plate material deteriorates due to battery cycling, heating and vibration which leads to paste shedding and loss of battery capacity.

Deep cycle batteries have plates which are far more robust and thicker leading to long cycle life and lower CCA by design. Some batteries have plates which are made from solid lead for really long durability ( >15 years) as found in stationary applications where weight and bulk is not an issue. Photovoltaic storage and oil rig control room backup applications come to mind.
 
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