Can Batteries be Restored?
Battery users and entrepreneurs often ask, “Can batteries be restored?” The answer is, “It depends.” Most battery failures are permanent and cannot be repaired, but there are exceptions. Sulfation on lead acid batteries can be removed if caught in time; crystalline formation, also known as “memory,” on nickel-cadmium can be dissolved through deep-cycling. Read more about Memory: Myth or Fact?, and “sleeping” lithium-ion packs can be boosted if they have been over-discharged. Read more about Safety circuits for modern batteries.
Permanent battery defects include high internal resistance, elevated self-discharge, electrical short and capacity fade. Poorly designed chargers, exposure to excess heat, harsh charge and discharge cycles, and inappropriate storage contribute to early aging. Let’s examine the cause of these non-correctable battery problems and explore what we can do to minimize them.
Low-capacity Cells
A manufacturer cannot predict the exact capacity when a battery comes off the production line, and this is especially true with lead acid batteries that involve manual assembly. Fully automated cell production in “clean rooms” also causes performance differences, and as part of quality control, each cell is measured and segregated into categories according to their inherent capacity levels. The high-capacity A-cells are reserved for special applications and sold at premium prices; the large mid-range B-group goes to commercial and industrial markets; and the low-grade C-cells may end up as consumer products in department stores. Cycling will not significantly improve the capacity of the low-end cell, and even though the cell may look good, the buyer must be aware of differences in capacity and quality, which often translate into life expectancy.
Cell Mismatch, Balancing
Matching of cells according to capacity is important, especially for industrial batteries. No perfect match is possible, and if slightly off, nickel-based cells adapt to each other after a few charge/discharge cycles similar to the players on a winning sports team. High-quality cells continue to perform longer than the lower-quality counterpart, and the cells degrade at a more even and controlled rate. Lower-grade cells, on the other hand, diverge more quickly with use and time, and failures due to cell mismatch are more widespread. Cell mismatch is a common cause of failure in industrial batteries. Manufacturers of professional power tools and medical equipment are careful in the choice of cells to attain good battery reliability and long life.
Let’s look at what a weak cell does in a pack that is strung together with strong ones. The weak cell holds less capacity and is discharged more quickly than the strong brothers. Going empty first, the strong brothers overrun this feeble sibling and the resulting current on a continued discharge pushes the weak cell into reverse polarity. Nickel-cadmium can tolerate a reverse voltage of minus 0.2V and a reverse current of a few milliamps, but exceeding this level will cause a permanent electrical short. On charge, the weak cell reaches full charge first and it goes into heat-generating over-charge while the strong brothers still accept charge and stay cool. The low cell experiences a disadvantage on both charge and discharge. It continues to weaken until finally giving up the struggle.
The capacity tolerance between cells in an industrial battery should be +/– 2.5 percent. High-voltage packs designed for heavy loads and wide adverse temperature ranges should have lower tolerances. There is a strong correlation between cell balance and longevity.
Li-ion cells share similar deficiencies with nickel-based systems and need management. The mandatory protection circuit supervises the serially connected cells by clamping the voltage when exceeding 4.25 and 4.35V on charge, and disconnecting the pack from discharge when the weakest cell drops to between 2.50 and 2.80V/cell. This prevents the stronger cells from pushing the depleted cell into reverse polarization. The protection circuit acts like a guardian angel that shields the weaker siblings from being bullied by the stronger brothers. This may be help to explain why Li-ion packs for power tools last longer than nickel-based batteries, which normally do not have a protection circuit.
The capacity of quality Li-ion cells is consistent and the self-discharge is low. A problem arises when the cells exhibit a discrepancy in self-discharge. This can be attributed to lower-quality cells or high-temperature spots in a large automotive battery, which hastens aging. Balancing is required and there are two methods: Passive balancing bleeds the high-voltage cells; active balancing shuttles the extra charge from higher-voltage cells to the lower-voltage cells without burning the energy. Active balancing is the preferred method on EVs.
With use and time all batteries become mismatched, and this also applies to lead acid. Shorted cells and those having high self-discharge are a common cause of cell imbalance and lead to subsequent failure. Manufacturers of golf cars, aerial work platforms, floor scrubbers and other battery-powered vehicles recommend an equalizing charge of 3–4 hours if the voltage difference between the cells is greater than +/– 0.10V, or if the specific gravity varies more than 10 points (0.010 on the SG scale). An equalizing charge is a charge on top of a charge that brings all cells to full-charge saturation. This service must be administered with care because excessive charging can harm the battery. A difference in specific gravity of 40 points poses a performance problem and the cell is considered defective. A 40-point difference is one cell having an SG of 1.200 and another 1.240. A charge may temporarily cover the deficiency, but the flaw will resurface after a few hours of rest due to high self-discharge.
Shorted Cells
Manufacturers are at a loss to explain why some cells develop high electrical leakage or a short while still new. The culprit might be foreign particles that contaminate the cells during manufacture, or rough spots on the plates that damage the delicate separator. Clean rooms, improved quality control at the raw material level, and minimal human handling during the manufacturing process have reduced the “infant mortality rate.”
Applying momentary high-current bursts to repair a shorted NiCd or NiMH cell has been tried but offers limited success. The short may temporarily evaporate but the damage in the separator remains. After service, the repaired cell may charge normally and reach correct voltages; however, high self-discharge will likely drain the battery and the short will return.
It is not advised to replace a shorted cell in an aging pack because of cell matching. The new cell will always be stronger than the others. Consider the biblical verses: “No one sews a patch of unshrunk cloth on an old garment. If he does, the new piece will pull away from the old, making the tear worse. And no one pours new wine into old wineskins. If he does, the wine will burst the skins, and both the wine and the wineskins will be ruined” (Mark 2:21, 22 NIV). Replacing faulty cells often leads to battery failures within six months. It’s best not to disturb the cells. Instead, allow them to age naturally as an intact family.
Shorts or high leakage in a Li-ion cell are uncommon. If this occurs, the cell becomes unstable and a massive amount of power can dissipate, leading to a possible venting thermal breakdown. Such a leak can be compared to drilling a small pinhole into a high-pressure gas pipeline and holding a match to it. The resulting explosion could rupture the pipe. Similarly, the rushing current in the cell heats up the tiny malfunction, causes a major leak and releases all energy within seconds. (Read more about Safety circuits for modern batteries)
Cell disintegration caused by internal disturbances lies outside the safeguarding ability of the protection circuit. Most cell failures occur when the battery has been damaged by shock and vibration, has been overcharged or has been overheated. Li-ion cells for electric powertrains and demanding industrial applications use a heavy-duty separator to reduce the risk of an electrical short. These batteries are larger than consumer-type packs. Saying that Li-ion has twice the energy density of NiCd can be a misnomer; some long-lasting Li-ion cells have a specific energy as low as 60Wh/kg, the same as NiCd.
| Caution: | Applying a high current burst works best with nickel-based batteries. Do not use this method for lithium-ion cells. |
Loss of Electrolyte
The loss of electrolyte in a flooded lead acid battery occurs through gassing, as hydrogen escapes during charging and discharging. Venting causes the electrolyte to become more concentrated and the balance must be restored by adding clean water. Do not add electrolyte, as this would upset the specific gravity and shorten battery life through excessive corrosion.
Permeation, or loss of electrolyte in sealed lead acid batteries, is a recurring problem that is often caused by overcharging. Careful adjustment of charging and float voltages, as well as operating at moderate temperatures, reduces this failure. Replenishing lost liquid in VRLA batteries by adding water has limited success. Although the lost capacity can often be regained with a catalyst, tampering with the cells turns the stack into a high-maintenance project that needs constant supervision.
Nickel-based batteries can lose electrolyte through venting due to excessive pressure during extreme charge or discharge. After repeated venting, the spring-loaded seal of the cells may not seal properly again, and the deposit of white powder around the seal opening is evidence of this. Losses of electrolyte may also occur as part of faulty manufacturing. Dry-up conditions result in a “soft” cell, a defect that cannot be corrected. On charge, the voltage of a “dry” cell goes high because the battery has no clamping action and does not draw current.
A properly designed and correctly charged lithium-ion cell should not generate gases, nor should it lose electrolyte through venting. In spite of what advocates have said, lithium-based cells can build up an internal pressure under certain conditions, and a bloated pouch cell is proof of this. Read more about The Pouch Cell. Some cells include an electrical switch that opens if the cell pressure reaches a critical level. Others feature a membrane that releases gases. Many of these safety features are one-way only, meaning that once activated, the cell becomes inoperable. This is done for safety reasons.
Comments
Dear Sir,
I am a missionary in Uganda E. Africa. As we have daily power outages here I have developed a battery backup system using a triplite 2400w 24v inverter and 16 200a sealed lead acid batteries wired in series and in parallel to make the 24v. I use the system powering a radio station and it would keep it going about 24 hr. The batteries have lasted about 1 1/2 yrs but I am getting only 4 hrs from the system. Batteries here are extremely expensive (around $300 each). I took one of the old ones I had replaced and popped off the flat cover and found 6 small holes for the cells. Is there a way that I can recharge these batteries? On regular car batteries here they drain the battery and refill them with a new mixture of acid and water and they seem to work for some time. If I could renew these batteries and even get another 6 months out of them it would be a very big savings.
Because of Christ,
Bryan & Cheri Stensaas
Missionaries in Uganda
Bryan, you do not state whether the batteries were new, or used. If they are only 1 1/2 years old and if there were times when your batteries were discharged for longer than few hours, sulphation is most likely the problem. In that case I would recommend you to try electrical desulphation. But maybe your charge/discharge currents were too high, or wrong charge voltages. Is there still enough water in the cells you popped cover from?
Bryan
You need to stop using garbage for batteries. Sealed lead-acid is useless for cycling - no matter what the “experts” say. The ONLY type of battery suitable for the kind of duty you describe are good, old fashioned, flooded lead-acid motive power (traction) types. They will last ten years. No other battery will last even half as long.
What is interesting about pulse technology is that there is evidence it does not actually reduce sulfation at all but gets rid of a totally different problem known in the trade as “open circuit” Symptom: The battery fails suddenly, with little or no warning..
It appears an ultra thin oxide layer or a sulfate layer can develop over the surfaces of calcium-lead alloy positive grids over time, (few years). The pulsing breaks down this layer.
All very low or ultra low maintenance and no-maintenance and all sealed lead-acid batteries have calcium-lead alloy positive grids. Pulsing works on these types of batteries. It does not appear to work on the “old fashioned” flooded antimony-lead alloy types, (nor on calcium hybrid types which actually have antimony-lead alloy positive and calcium negative grids).
Simply pulse for several hours and the “dead battery” problem seems to disappear.
John- would you agree that a wla batt that has been left alone for say 6 months & will not take a charge & measures say 11v is effectively dead? Yes- then my pulser or if you like batt zapper is connected- the pulses measure at 1st 350v- then over period of several hrs drop to say 15v- then bat is put on constant volt charge of 14v- when the amps have dropped to say 50mA that batt is fully charged- confirmed by a high rate (200A) discharge test- so I have saved that batt! And it was the zapper that did it! And NO- the zapper does not charge the batt- it can’t- that would be energy from nothing!- I feel we are getting somewhere here- educating us & others. On a slightly diff sub- do you agree that a batt in a vehicle with a gen lasts twice as long as a batt in a vehicle with alt- seems to be gen has 150 magnetic moments/sec & alt has 350 mms- lower figure leads to deeper charge of plates whereas alt leads to surface charge- so by that reckoning a home batt charger from mains, thru a regulator filter setup, should be as good for extend batt life as a gen- if bat periodically charged using previous setup. One thing I know for sure- the worst thing for a wla batt is sitting on a floor(even though kept fully charged- & periodically shook or put on vibration machine to alleviate stratification)- so- just use batt in vehicle- say weekly- long runs. I have had batts from tips last 5 years! Cheers- Bevan.
Bevan
I am not criticizing pulsing but I am very skeptical about the effect it has on sulfation. And what you are describing supports, rather than contradicts my contention.
Lead-calcium alloy positive grids are garbage. I have hand-built hundreds of lead-acid battery cells in my experiments. I have obtained automotive battery plates in an unformed condition from battery manufacturers in the US, Brazil, South Africa, Ukraine, etc., etc.
I have built identical rated cells from sets of positive plates made with antimony alloy and calcium alloy grids, negative plates all made with identical calcium alloy grids. (The antimony positives, calcium negatives are called hybrids.)
Simply connected all the cells in series and cycled them from 100% down to 20% and back up, etc., etc.. After 10 cycles the antimony grid cells had gained 10% in A-hs and the calcium grid cells had lost 80% in A-hs. This told me there is something weird going on with calcium. All the positive plates looked exactly the same but the calciums were not working any more.
Yes, the cells can be restored by pulsing. No, it is not sulfation.
Lead-sulfate requires at least the energy of a full charge to eliminate. An oxide layer requires only that the film be pierced to a sufficient extent. Then, once pierced, the battery can be charged in the ordinary way.
The problem can be treated chemically as well. Not by sulfation potions but by a material that attacks the thin oxide film. I have restored batteries that way.
To paraphrase Galileo Galilei, “In questions of science the opinions of thousands are not worth the humble reasoning of a single individual”.
Bevan
An old fashioned generator is controlled by a voltage sensitive relay. The generator “pushes up” the battery voltage, hence creates a charging current. When the voltage is high enough, the voltage relay opens the circuit to the field, and the field slowly collapses, thereby reducing the battery voltage. As soon as the voltage has fallen sufficiently, the voltage relay closes, the field builds up and the cycle is repeated.
An alternator produces three phase, which is rectified and fed to the battery. There is a solid state voltage controller that operates the field in exactly the same way. Alternators are inherently more robust than generators in that they can be rotated much faster. This allows the alternators to begin charging at lower engine RPM.
The only factors I can see that might affect battery life are a generator’s inability to keep a battery charged in stop-start driving, leading to sulfation, (!) and an incorrectly calibrated voltage regulator that can either undercharge or overcharge the battery.
Alternators are several orders of magnitude more reliable than generators.
Automobile manufacturers often put batteries near exhaust manifolds. That is just plain dumb. The regulator does not “know this”, so the battery ends up being severely battered.,
Modern cars are festooned with current gulping gadgets that stay on 24/7. So the batteries end up being discharged, often at more than 50 mA continuously. The self discharge of a modern battery is overwhelmed by this drain and the battery ends up permanently undercharged. This can reduce battery life to under 2 years. The battery manufacturers love it. The automobile manufacturers could not care less. This is bad engineering and the consumer is therefore being deliberately ripped off.
Good day, very interesting topic, Hi John, i am setup a hybird 1kw solar and 1kw wind system in my house running with 24 system, day time are running with direct grid tie inverter to reduce the amp from the fit, and once the battery fully charges sunlight down then will change to pure.true sine inverter to supply all lights and elctronic system, this process is running every day and times, John, please kindly consult me, if the system like above, what type of the batteries is suitable for me? Battery cost are really killing me if i choose the wrong type for my need. Thank you so much in advance. Cheers to going green.
Andersen
There is only one type of battery that is (a) economical enough and (b) technically suited, both at the same time, to daily deep cycling. Old fashioned, flooded lead-acid motive power.
There are three varieties. (1) The old fashioned golf-cart type; (2) the American flat-plate-positive type; (3) the European tubular-positive-plate type. They get more expensive from (1) to (2) to (3). The first will last two+ years, the second six+ years and the third type will last 10 years.
Lead-acid motive power does not mind being partially or totally discharged. By totally I mean down to 1.75V/cell or 20% state-of-charge. You absolutely MUST ensure the batteries reach 100% gassing charge, (2.55V/cell), at least once every two to three weeks. You will need to water the batteries from time to time. Amazingly, most, (not all), users in the USA, South Africa, Australia use tap water! I recommend inexpensive deionized or reverse osmosis.
Do not, I repeat, do not believe the people that tell you that VRLA, sealed, maintenance-free batteries are suitable.
Bevan. And what is your peak current at those 880kHz? At least roughly..?
I have tested circuits at hundreds of kilohertz as well, even at several MHz but they did not produce better results than the unit I currently use.
Are you measuring the specific gravity of the batteries you rejuvenate? Is it rising as you pulse? Your results are really lightning-fast,
Are you using inductive or capacitive pulses, and positive or negative (into or out of the battery)? With sharp <100ns or soft edges? Could you maybe share the schematic?
Mine (the one I talked about) is just an ordinary boost converter powered by a LC low pass filter from the battery being desulfated .. Just like the old Alastair Couper design, but more powerful. And the electrical efficiency is about 90%.
I have tested circuits at hundreds of kilohertz as well, even at several MHz but they did not produce better results than the unit I currently use. In one experiment, pulsing the battery at 16kHz has brought SG from 1,18 to 1,22 in three days but then suddenly stopped rising, after few days of no progress I tried to retune the pulser to 12kHz and the SG started to rise again and needed about 5 days to stop at 1,25 - 1,26. So now I am using frequencies from 1kHz to 12kHz with good results.
Are you measuring the specific gravity of the batteries you rejuvenate? Is it rising as you pulse? Your results are really lightning-fast .. maybe it is really the calcium insulating layer you are treating .. but if you measure SG and it rises as you pulse, it is sulfation, i think John would agree ..??
Battery plates in sulfuric battery acid have a nanoscopically thin surface or boundary layer that presents capacitively. (This can be exploited by introducing activated carbon into the negative plates, turning the lead-acid battery into an ultra- or super-capacitor.)
I am guessing. I suspect that high frequency pulsing simply charges and discharges this “capacitor” in ordinary lead-acid batteries, sapping energy from the pulses. So reducing the pulse rate probably makes more energy available to do the job at hand.
The battery Matej describes was obviously in a discharged state and the pulsing caused it to become charged. However, I think the battery had both an oxide layer problem and was in a reversible sulfation condition at the same time. I suspect a couple of hours of pulsing, followed by straight charging would have sorted it out.
John & Matej- all I know is how to get more life out of batts- I do not know if calcium or other material is being used in plates- the manu does not say usually! As to sg- this is a oxymoron!- & completely irrelevant to wla batt life! As is o/c term voltage! I have had a car batt that started my car for 5 years once a week- long runs- the o/c v were 12’2v- yet that batt started that car reliably time & again! It failed with an o/c cell eventually. I have a batt from the tip that the sg says is dead flat!-yet that batt puts out 200 amps with very little volt drop! Ocv is 12v5(fully charged). So my friends- what the books say & what is real are different things!. Matej- the circuit I used to build my zapper came from Silicon Chip magazine- but I used my own up rated parts wired direct- eg- they had 100v mos-n-fet I used 500v- etc-etc-etc- the circuit is inductively coupled using my own wound air inductor of about 100uH. Download circuit from SC website. Another question for the expert John- there used to be batt recond places that would sell one a recond batt for say $20 at time when new was say $120- WITH 3 MONTH WARRANTY. I saw what they did- got lots of batts- put em on high charge rate- those that charged up- they tipped old electrolyte out- refilled with new electrolyte- seemed to work for while!. Any scientific validity to what they did? Cheers- Bevan.
Hi Bryan.So you pulse mainly car batteries? I mostly do the deep cycle batts from PV , UPS systems etc. Yes I can agree that o.c. voltage is not very relevant, as it is also temperature dependant etc. But I really have experience that SG is very relevant in terms of battery Ah capacity - this is not only theory from a book, but mainly my own experience with many, mostly deep cycle batts: Battery that has low SG when fully charged, does have low Ah capacity. I have never had a battery that has low SG and has good Ah capacity. It seems that the capacity is roughly proportional to SG of the weakest cell: 1,15 -little or no Ah capacity to 1,28 -full Ah capacity .
When SG is low, the CCA (cold cranking amperage, that’s what starts the car) is also lowered but even this lowered rate might be enough to start a car fine: Actually right now I am pulsing a 60Ah car battery, that has 5 cells at 1,24 and one at 1,20 and still started the engine normally with no problems. But there were some problems with the engine recently - it won’t start and that is where they found the battery has low capacity - it will crank only for few seconds. They had to keep it on a charger constantly when they serviced the engine.
So I really believe that SG is very relevant to battery Ah capacity - I believe if you would do the Ah tests in deep cycle batteries, you will find the same.
John - the battery I described was definitely NOT in a discharged state - it had OC of 12,8V right before pulsing started and this did not change after pulsing, yet the SG and Ah capacity changed dramatically. But yes there might be the oxide layer problem too, who knows, but SG measurements before and after pulsing clearly say it was mainly sulphation.
Prior to pulsing I always put the batteries on 13,7V for at least 24hrs, but mostly two-three days at room temperature, before doing any measurements and pulsing.
- John,
Thanks for fast respone, so you means even AGM & gel series battery is not good as the batt you had mention?
The 1st you mention for the life time are too short.. 2 years average, overall, i did not saves, the 2nd, will not save as much.. 3rd is too expensive…
Especially all batteries are imported, our government tax is blood sucker, all oversea imported batteries price so high price here… So upsad.
Matej,
I believe 13.7V is no more than a high float voltage. It does not charge a battery in the accepted sense. A battery that reads 12.8V could be at full state-of-charge or at full state-of-discharge, depending on a number of factors. Battery voltage is meaningless when measured or expressed arbitrarily. (This is more fully described on evbatterymonitoring.com - a website run by a well known state-of-charge instrument manufacturer.)
Did you treat your battery to 13.7V prior to measuring 12.8V? That would definitely give you a false indication of the condition of the battery.
Sulfation defines the battery plates as functionally inoperative. This must be reflected by a much lower than normal battery voltage.
Logically, if you apply 13.7V to a sulfated battery, then disconnect and the voltage stays at 12.8V, the battery either was not sulfated or became desulfated in the process. The voltage of a sulfated would collapse on disconnection.
The information you present regarding SG fits a situation involving (a) a battery that is simply discharged or (b) a battery with an oxide layer problem.
Andersen - the AGM and gel are twice as expensive and quarter to an eighth as good as flooded lead-acid. I personally would definitely use Trojan golf-cart batteries or any other brand that uses rubber based separators. I would not touch batteries with polyethylene separators. If you are terribly worried about cost, give plenty of extra TLC to the batteries you use. You might then get 6 years out of your golf-cart batteries, or even much more.
John: Yes I did charge the battery at 13,7V for 3 days at room temperature, which according to vast majority of commercial lead-acid battery datasheets leads to full charge. Actually they mostly specify 100% charge in 20hrs. Most UPS systems use only float voltage charging at 13,5 to 13,6V (room temp). Then, I completely disconnect the battery and leave it like that at room temperature for several hours to stabilize. Then and only then I measure SG, voltage, capacity test etc.
In the early stages of my experiments I also tried to charge with higher than float voltage, 14,4V and more .. but this did not lead to any significant improvement in capacity or specific gravity. Many times it only colored the acid to dark red or brown, and caused the acid to smell bad.
Where did you get the information that “Sulfation defines the battery plates as functionally inoperative. This must be reflected by a much lower than normal battery voltage.” ??
That is completely false in terms of o.c. voltage. It only applies if the voltage is tested under load, which is not what I’ve been talking about. Sulfation - partial coverage of plates by crystallized lead sulfate - reflects to increased battery resistance and lower capacity. That may reflect to lower voltage of battery UNDER LOAD. But it has nothing to do with open-circuit voltage. I thought you know this, you really surprise me now.
I already wrote that stabilized o/c voltage of sulfated (small Ah capacity) and desulfated (good Ah capacity) is virtually the same. I have had several 100Ah batteries that had only 2-3 Ah EACH as per C/20 load test. They have been left totally discharged for more than 2 weeks. They were measuring stabilized 13,0 - 13,1V OPEN CIRCUIT, just as almost any fully charged 12V battery i have had. None of many charging attempts of mine or their former owner were successful. After I popped the covers, SG was 1,18 in the weakest cells. After pulsing for 2 weeks the SG of weakest cells rose to 1,24 and the C/20 capacity of one battery was 38Ah, the other 48Ah. The stabilized voltage was still in the range 13,0 - 13,1V !!
They were already returned to the PV system they came from, as the renewed capacity is satisfactory for their owner.
You obviously try, for some reason, to undermine the concept of pulse desulfation while continually ignoring the main proof of this concept that I have mentioned several times: Specific Gravity of sulfated battery being charged with DC voltage for days, does not increase or only little, but with pulsing it increases much more, many times to 1,28 or close to that.
You never tried to explain this, so please do before commenting on pulsing as ineffective in sulfation removal.
- John,
May i know what is TLC? Just add it in for every cell? Thanks
Anderson - absolutely yes. TLC stands for Tender Love and Care.
Sorry, I meant Andersen.
Matej
On application of 13.7V, if a battery is NOT sulfated it CAN accept a charge. If a battery IS sulfated it CANNOT accept a charge. By definition. Electrochemistry 101.
Good day, John,
Finally i found the Trojan batteries distributor in my country, may i get your consult again? Which modal of Trojan flooded battery to suit for my 24v system and plan like last times i said. And i am also worry, i keep my batteries at indoor inside my storeroom, i am afraigh the gas will BOOM my store.. \_/
Andersen
I keep batteries indoors, on charge, in a store. So what. You can ask for flame arrestors as well as auto filling if you are that way inclined. I personally would not bother. I cannot advise you on battery rating. Trojan have a solar, wind advisory department. Search trojan batteries flame barrier, etc., etc. I would use T105 or similar. They will try to sell sealed types. Refuse. Do not allow yourself to be their AGM/gel guinea pig.
Good day, John,
Thanks for so many prompt reply, today i look at my store, i have many SLA battery, i am wonder if i can open the top cap, and fill in distill water or table salt, do you think will be work better?
Andersen, I would use only distilled water.
Andersen, as John says. I would also not use anything but distilled (or osmotic) water. Yes you can open the top cap on SLA (VRLA), that is what I do often. However with new battery, which you do not charge with higher current than C/10 and do not let it stand discharged and thus sulfate, you have one or two years minimum before water needs to be added. Just do a capacity test every few months, if capacity is >80% I would not open the caps. Maybe just few days of electrical pulsing will recondition it close to 100% again.
Once upon a time the battery industry actually made good batteries. Their ONLY disadvantage was that they needed watering. Then the industry came up with a maintenance-free concept - saying the automobile manufacturers were demanding maintenance-free. Yet cars still needed water for the radiator, oil for the engine and air for the tires.
The electrochemistry in maintenance-free sealed lead-acid must be run in a very peculiar way in order to stop the batteries drying out. Gassing can be reduced, never eliminated. So what they do is they hold the electrolyte in glass fiber matting or gel that has minute cracks all over. The oxygen that is given off by the positives travels via the matting or the cracks in the gel to the negatives, where it combines with the hydrogen that is given off, to form water. Sounds like a brilliant idea until it becomes apparent this recombination activity discharges the negative plates! You can charge and charge and charge. The negatives will always be partially discharged. Guess what! The negatives sulfate up!
The positives of batteries made long ago were made of lead-antimony alloy - the new ones are made with lead-calcium alloy. This helps to reduce gassing but introduces all kinds of extra problems. These grids cannot tolerate overcharging. They cannot tolerate overdischarging. The grids either fall apart or they develop “open circuit”, an oxide layer that leaves the active material isolated.
I was involved in a project to build the biggest battery in the world. When people have to spend tens of millions of dollars on a battery installation, they generally try to do their best. The battery was run from the local 220KV grid, via transformers and inverters. It had a capacity of 40MW-h. Used for load-leveling in California. It was charged during the night, discharged during the day. The battery absolutely had to be designed for maximum life. The design life was 4000 deep cycles. The cells were the same size as submarine battery cells. The positives were American flat-plate with grids made of lead-antimony-arsenic. The negatives had lead-calcium alloy. The separators were made of porous rubber/ glass fiber. The electrolyte was liquid and the battery was filled with watering caps. It got me interested in finding commercially viable ways of making batteries last longer, (without the use of arsenic and with only the lowest percentage antimony)
I am not expressing metely an opinion when I recommend flooded motive power batteries for cycling in wind and solar.
Dear sir
I am using 54v 300ah vrla battery bank out door. I don’t have backup I found that some cells are faulty it discharging soon for that cells can I add distilled water and charge
If your cells have removable tops-check electrolyte level (if your cells are flooded) if not flooded- nothing you can do- except find reason for failure- remove each cell to check- if o/c failure- zapper can work- also sulphation failure- as has been said many times- SLA incl VRLA have limited life- esp if deep cycled! ( though label may state differently!). If electrolyte level is below plates, only add enough low ppm water to cover just - charge- when fully chgd- top up( electrolyte level rises with charge). General advice without seeing your batt/s- setup.
N.senthil: I agree with Bevan Paynter. I should point out that without knowing the age of your batteries, others are unable to work out the cause of the problem. Batteries age, like people. Have accidents or pass away, like people.
How does this article stand with todays improved “Smart Chargers” are there any significant changes now, in 2011??