Now, your dear battery is completely broken. Problems such as boiling after five minutes of connecting to the charger began, or it does not take charge, but an ordinary car light completely discharges it in just a few minutes to zero. And so, you stand and think, "What to do, throw away or try to restore the power source." Today there is a fairly large number of various options for reviving the battery, and one of them is the polarity reversal of your power source. You already have nothing to lose ...
But be warned, these are very drastic measures, it must be done when there is no other way out! In particular, the sulfation of the food source is so strong that it cannot be removed by any methods, and even by desulfation methods! Nevertheless, if these methods work, do not resort to polarity reversal, this will simply kill your battery for sure.
What is polarity?
For those who do not know, a polarity reversal is a change in the poles of a power source, by the method of one hundred percent discharge, or otherwise "to zero", and then a charge under other poles. This is done to restore the productivity of the battery, to increase its capacity.
To put it simply, you simply swap plus and minus, the terminal that was positive became negative, the negative terminal became positive. Nothing complicated, right?
For reference: minus plates are made of lead, while plus plates are made of lead dioxide.
Why do the polarity reversal?
Quite simply, this is a war with the sulfation of the plates and the renewal of the capacity of the power source, because, as a rule, sulfates very much clog the plus plates. In order to destroy them, you need to make minus plates from the plus plates! This is exactly what is done thanks to the polarity reversal.
Well, for example, you have a non-working battery in your house or garage, and after completing this easy process of polarity reversal, you can give it a second life. Of course, it will not function flawlessly, but in the summer you can operate it without problems, but it will not be suitable for winter at all.
Yes, this is a radical method and shouldn't be done if your power source
lost in general 10 - 20% capacity.
We are going through this frightening process.
Yes, there are many words that are frightening and difficult at first glance. But it’s very, very easy to do.
Take a non-working battery. That is: it rapidly boils, its capacity is from 10 to 30% of the nominal, very, very rapidly discharges to zero.
Boils quickly, literally in a few minutes
Of course, this power source is not able to help start the car's motor, it just won't have enough power. Therefore, a polarity reversal is absolutely necessary for such a battery. Let's get started:
- Thin the power source one hundred percent. Next, we hang any load on the terminals, as a rule, an automobile light bulb is enough. Then we need to change the terminals from the charger, in particular, we connect the negative wire to the positive terminal! It is clear that negative - to positive.
- We complete the charging process. The power source, no matter how surprising it is, will start taking charge, moreover, very energetically, but a very strong heating of the battery will begin, this tells us that the battery begins to transform the "poles", and the plates in the middle are changing.
- Initially, you need to give a large current, about ten percent of the battery capacity, but then you need to charge with a current of two Amperes. In addition, I advise you to hang up an additional resistance, so that it takes over the main heating. A small resistor will suffice.
- We expect the cans to boil completely at low current.
After this easy process, your power supply will reverse polarity and gain the required capacity. There are situations that you can resume up to 90% of the nominal without any problems. This is the whole process, as you can see it is quite easy. But it will not always be useful to you.
Correct car maintenance is necessary for the vehicle to work flawlessly. But even with proper care, your car battery loses capacity. If the cause of the malfunction is a precipitate of lead sulfate on the surface of the plates, polarity reversal can save, as an extreme recovery operation. Experts say that shock operation can lead to complete internal destruction or partial restoration of capacity.
Does your battery take no charge, starts boiling in 3-4 minutes, and discharges in a matter of minutes with a car light? If the electrolyte is light, there is no turbidity in it, and a white coating is visible on the lead plates - sulfation has occurred. The insoluble sediment does not allow ions to approach the plate and charge it. You tried to destroy scale by all known methods, didn't it work?
It remains to hand over the used battery for recycling. Only when all desulfation methods have been exhausted is polarity reversal applied - changing the charger connection from the positive terminal to the negative terminal. In this case, the lead plate of the battery receives a positive charge, and the lead dioxide is negative. New low-cost battery models have thin lead plates, they can collapse before the sulfate dissolves. Reversing the battery polarity can have bad consequences if there are banks with a short circuit or crumbled active mass.
What is the danger of polarity reversal when lighting
The wires for lighting are not always marked for connecting the plus and minus of the battery. In the dark, crowded, in a hurry, you can confuse them. This is the only reason for polarity reversal when lighting a car. Therefore, in all instructions there is a point, check the connection additionally.
The reversed wires will connect 2 batteries in series, giving a voltage of 24 V. At the output, a jumper - a short circuit is organized. Consequences - hand burns, fire. At this point, a smaller battery may explode.
Often, contrary to the instructions, while the donor car is still turned on, both cars may have an ECU failure, a diode bridge may burn out. But if you catch yourself and remove the wires quickly, it will cost a few fuses. After detecting an error, the vehicle battery must be quickly discharged, checked and properly charged from the mains. In modern cars, protection of the battery and the on-board network from polarity reversal is provided.
How to reverse the polarity of the battery
Any battery, having worked for 2-3 years, loses its capacity for various reasons. Some of the cells may shrink due to the crumbling mass. A short circuit will happen and the jar needs to be replaced. Sometimes the electrolyte turns black from the oxidized plate, sometimes the high resistance to charging currents creates a white solid deposit on the plates. Sulfation is removed in different ways, but if plaque remains on the plates, an extreme way is to reverse the polarity. You cannot use the method if there is little electrolyte in the cans, you need to add. Older battery models have thick lead plates and are better able to withstand polarity reversals.
Maintenance-free calcium batteries are cleaned from sulfation by impulse currents. The polarity reversal is contraindicated for them - it is impossible to perform a deep discharge and organize "boiling". Even measuring the density of an electrolyte in an unattended device is problematic.
What can the polarity reversal of a lithium battery cause? Such batteries are demanding to operate, do not tolerate overvoltage and deep discharge. The batteries work with balancers and special protection controllers that prevent going out of safety mode. Devices are not subject to sulfation, polarity reversal is unacceptable.
Procedure for battery polarity reversal
The operation is carried out in a ventilated room. It is necessary to control the process by adhering to the recommendations. Make sure the cans are free of caps before charging. The mixture released during the reaction is explosive.
A battery polarity reversal scheme from specialists is proposed.
- First of all, the battery is discharged to zero by an external resistance, as you should make sure, and for fidelity, even bridge the contacts.
- We connect the battery to the charger by changing the polarity - red wire to minus, black to plus.
- We set the voltage to 14.2 -14.8 V, current 2 A. The battery is being charged, while the temperature in the banks rises. It should not be allowed to heat above 60 0, reducing the charging current and voltage.
The process can take several days. During this time, the insoluble precipitate gradually dissociates lead ions into the electrolyte solution, and its density increases. At the end of charging, the hydrometer will show the operating parameters, the plates will be cleaned. This process is called polarity reversal, and the battery is left to work like this after capacity is restored.
Double polarity reversal of the battery is a process when, after removing the first charge by any resistance, the device is again put on charge, but in the forward direction. At this moment, the classic polarity returns, and the car battery restored by the polarity reversal will remain operational for years.
We suggest watching a video on how to restore a battery using the polarity reversal method.
Battery - do it yourself polarity reversal
Before reversing the battery polarity yourself, you need to try to dissolve lead sulfate in other ways. Danger of the process in the design of the battery. Russian European manufacturers use thicker lead plates, they can withstand the load of polarity reversal. But the closure of the cans in them is not excluded. Therefore, you should fill your hand on a battery prepared for disposal due to sulfation.
The process does not need to use a large charging current, speeding up the process. It is better if the boiling is small bubbles, at a temperature of 50 0. Observe personal safety, wear protective goggles and rubber gloves.
The results of battery recovery by polarity reversal are different. Reviews of this operation are controversial, but they boil down to the fact that it is better to buy a new battery than to flinch every time it is difficult to start the car engine.
Battery polarity reversal, recovery - video
We suggest looking at an accessible explanation of a specialist, whether it is necessary and how to reanimate the battery by reversing. The author simply sets out step-by-step instructions with his own recommendations.
The authors of the article have been dealing with the problem of extending the performance of lead-acid batteries for several decades - technologies for the recovery of lead-acid batteries have been developed, hundreds of laboratory works have been carried out on batteries with a capacity of 4 to 2200 A / h and a voltage of 1.5 to 110 volts. Thanks to the cooperation of the laboratory and organizations: the Russian Railways, Rechflot, Avtotrans, Battery Companies, Minatom and other companies, a number of charging and recovery devices have been developed, which have been tested in single copies, recommendations have been given for operating batteries, restoring their technical characteristics, reducing explosive emissions hydrogen and oxygen, improving the environmental situation and reducing the cost of charge and recovery work.
Batteries lose their properties not only in industrial installations, but also in modern vehicles after two to three years of operation.
The reasons for the decline in quality are the lack of preventive maintenance to restore the electrodes of the battery plates.
Batteries in cars are used in a mixed mode of operation: when starting the engine, a significant starting current is consumed; during a trip, the battery is charged in a buffer mode with a small current from the generator.
If the vehicle's automation is faulty, the charging current may be insufficient or lead to overcharging - at higher values.
Crystallization of the plates, increased charge voltage, premature electrolysis with abundant release of hydrogen sulfide and insufficient capacity at the end of the charge accompany the operation of such a battery.
Signs of sulfation of the battery plates:
- Reducing the battery capacity;
- Increased voltage on the electrodes;
- Boiling and gassing;
- Heating and warping of plates.
It is not feasible to restore the normal operation of the battery directly from the car generator due to the slight excess of the generator voltage over the battery and the constant component of the charge current - chargers are used for this.
The battery discharge current for 10 hours is always equal to the battery capacity. If the voltage during the discharge dropped to 1.92 volts per cell, earlier than ten hours, then the capacity is also that much less.
Some vehicles use two batteries with a total voltage of 24 volts. Different discharge currents, due to the fact that the entire load with a voltage of 12 volts (TV, radio, tape recorder ...) is connected to the first battery, which is powered by the battery in the parking lot and on the road, and the second is loaded only during starting the starter and warming up the candle in a diesel engine. The voltage regulator not in all cars automatically monitors the battery charge voltage with the difference in winter and summer time, which leads to undercharging or overcharging the battery.
It is necessary to regenerate batteries with a separate charger with the ability to regulate the charge and discharge current on each battery.
This need prompted the creation of a charging-discharging device for two channels with separate regulation of the charge current and discharge current, which is very convenient and allows you to select the optimal recovery modes for the battery plates based on their technical condition.
The density of the electrolyte should, after the battery is restored, correspond to the passport for the given area of \u200b\u200boperation, in the north the density is higher than in warm regions - in summer and winter.
The density should not be adjusted by adding electrolyte.
Capacity recovery by polarity reversal ... When absorbing organic surfactants on negative plates, a method of periodically reversing the polarity of the battery is used. Applying a high potential to the negative plate burns out surfactants that cause sulfation of the plates.
The use of a cyclic recovery mode leads to a significant decrease in the yield of hydrogen and oxygen gases due to their full use in a chemical reaction, the internal resistance and capacity are quickly restored to the working state, there is no overheating of the case and no warping of the plates.
Battery recovery by impulse current ... Impulse currents in shape, amplitude and time differ significantly from sinusoidal.
The pulse amplitude of such a recovery current, as a rule, exceeds the average charge current by 5-10 times. Such a current cannot damage the battery plates, but it is able to melt old lead sulfate crystals in a short time. With an average charging current of five amperes, the pulse can reach an amplitude of 50 amperes, it is possible to achieve such a current amplitude with a significant charge voltage of 24-26 volts.
Due to the short pulse of several microseconds, battery heating and boiling are practically not observed, recovery can be performed indoors in the absence of forced draft.
The power of the charging current on the battery does not exceed the power of a simple charger on a diode bridge, and the power of a single pulse can reach 1200 watts, which is enough to convert lead sulfate into amorphous lead.
Between two pulses of charging current, there is always a period of time without current, sufficient to restore electronic equilibrium in the electrolyte.
To speed up the recovery process, the circuit should be supplemented with a circuit of a discharge current of a small value.
Charger and recovery device, made according to the scheme (Fig. 1). The circuit and transformer fit into a standard computer power supply case.
Device characteristics:
Mains voltage 220 V
Secondary voltage 16-18 V
Transformer power 100 W
Charge pulse time 2-5 ms
Discharge time 1-3 ms
Recovery time 5-12 hours
Charge current 1/20 C.
C-capacity in A / hour.
Discharge current 0.05-0.2A
Discharge current when charging asymmetric current should be no more than 1/10 of the charge current.
New technologies for charging and restoring batteries make it possible to reduce the power for regenerating the plates, although the charging of batteries in modern cars has not undergone significant changes - over a period of more than a century, which, as before, leads, practically eternal batteries, to premature crystallization, an increase in internal resistance and a deterioration in starting characteristics.
The master oscillator in the circuit is implemented on two transistors of different conductivity VT1 and VT2. An analogue of a two-base diode is included in the bridge circuit - on the left, resistors R1R2R3R4, on the right, R5R6.
The generator is powered from a parametric stabilizer for a stabilization voltage of 16 volts on the VD1VD2R9 elements.
The transistor generator is easier to modify than the classic double-base diode generator. In this version, there are external circuits for current regulation - R1 with limitation by resistor R3. The circuit for maintaining the temperature regime of the circuit is made using a thermistor - R2.
To supply current of both polarities to the battery, it is not required to install two identical generators; a positive recovery pulse is generated by the thyristor VS1.
The control pulse from the emitter of the transistor VT2 through the limiting resistor R7 is fed to the internal LED of the optocoupler U1. The internal transistor of the optocoupler opens the current through the limiting resistor R8 from the anode of the thyristor VS1 to the control electrode, with a negative half-wave of the sinusoidal voltage of the secondary winding of the transformer T1 at the cathode VS1. The current of the open thyristor VS1 goes to charge the battery GB1.
The turn-on time depends on the ratings of the resistors R1, R2, R3 and the capacitor C1.
With a positive half-wave on the transformer T1, the thyristor VS2 opens and the discharge current enters the battery, synchronously with the charging current, but smaller in magnitude. Since the discharge current should not be higher than 1/10 of the charging current, the discharge current limiter, resistor R11.
The R13 VD3 circuit creates, for starting, an offset on the negative bus of the generator on transistors VT1 VT2, with the thyristors VS1VS2 closed at the initial moment.
The pulse width of the generator should overlap the width of the full period of the sinusoid of the secondary winding - more than 10 msec.
The charge-discharge current is regulated by the resistor R1.
Thermistor R2 reduces the charging current when the thyristors overheat.
Elements R12 HL1 PA1 indicate the correct connection of the battery to the charging and recovery device and the total recovery current.
The circuit uses radio components, the characteristics and possible replacement of which are recommended in Table 1.
|
No. according to the scheme |
Name |
Scheme type |
Possible replacement |
Note |
|
Resistor |
Variable |
|||
|
Resistor |
||||
|
Resistor |
||||
|
Capacitor |
||||
|
Capacitor |
||||
|
Capacitor |
||||
|
Transistor - PNP |
||||
|
Transistor - NPN |
||||
|
Zener Diodes |
||||
|
Optocoupler |
||||
|
Transformer |
TN-1 24V 100W |
CCI, TS 18-24 V 60-100 watts |
||
|
Thyristor |
With radiator |
|||
|
Thyristor |
New mount |
|||
|
Ammeter |
M4100 5Ampere |
|||
|
Light-emitting diode |
Any colour |
|||
|
Resistor |
||||
Setting up the circuit begins with checking the installation. Instead of a GB1 battery, a 12 volt 20-50 candle light is connected to the output sockets, the R1 current regulator checks the change in brightness from the minimum to the maximum level. The discharge current can be checked by connecting an ammeter to the open circuit of the anode circuit of the VS2 thyristor.
Thyristor VS1 and transformer T1 are installed outside the board.
Current regulator - R1, ammeter - PU1, LED - HL1 and switch SA1 are mounted on the front panel.
Thermistor R2 is mounted on the heatsink of the VS1 thyristor and monitors its overheating.
References:
1. V. Sorokoumov. Impulse charger. Radio No. 8, 2004 p.46.
2. I.P.Shelestov. Useful schemes for radio amateurs. Book 5, p. 108. Solon-Press. 2003
3. B. Sokolov. Improvement of electronic ballast. Radio No. 6, 2006 С27.
4. A. Petrov. Impulse power block. Radiomir. No. 7,2002 p.12.
5. V. Konovalov. "Cars and Batteries". Methodical manual of the DTT Center. Irkutsk. 2009 C70.
6. M. Dorofeev. Reduced interference from switching power supplies. Radio No. 9.2006 S38-40.
7. V. Konovalov. Charger on a switching power supply. Radio amateur No. 10,2009g S.36-39.
8. V. Konovalov. M. Malkov. Charger based on thyristor inverter. Radio amateur No. 12, 2009 P.46-48.
List of radioelements
| Designation | A type | Denomination | amount | Note | Score | My notebook |
|---|---|---|---|---|---|---|
| VT1 | Bipolar transistor | KT361A | 1 | MP41-42B | Into notepad | |
| VT2 | Bipolar transistor | KT815B | 1 | Analog: KT972 | Into notepad | |
| VD1, VD2 | Zener diode | D814G | 2 | D814D | Into notepad | |
| VS1 | Thyristor | T122-25 | 1 | KU202B-N. With radiator | Into notepad | |
| VS2 | Thyristor | VT139 | 1 | KU201B-G | Into notepad | |
| U1 | Optocoupler | LTV817 | 1 | Analog: 816 | Into notepad | |
| HL1 | Light-emitting diode | AL307B | 1 | AL307G | Into notepad | |
| C1 | Capacitor | 1 uF | 1 | Into notepad | ||
| C2 | Capacitor | 0.22 μF | 1 | Into notepad | ||
| C3 | Capacitor | 0.1uF 100V | 1 | Into notepad | ||
| R1 | Variable resistor | 47 k Ohm | 1 | Into notepad | ||
| R2 | Thermistor | 220 kΩ | 1 | Into notepad | ||
| R3 | Resistor | 3.3 k Ohm | 1 | 0.25W | Into notepad | |
| R4 | Resistor | 120 kΩ | 1 | 0.25W | Into notepad | |
| R5 | Resistor |
All batteries have an expiration date, with multiple charge / discharge cycles and many hours of use, the battery loses its capacity and keeps its charge less and less.
Over time, the capacity of the battery drops so much that its further operation becomes impossible.
Probably many have already accumulated batteries from uninterruptible power supplies (UPS), alarm systems and emergency lighting.
A lot of home and office equipment contains lead-acid batteries, and regardless of the battery brand and manufacturing technology, whether it is a regular serviced car battery, AGM, gel (GEL), or a small flashlight battery, they all have lead plates and an acid electrolyte.
At the end of their operation, such batteries cannot be thrown away because they contain lead, basically the fate of disposal awaits them, where lead is removed and recycled.
But nevertheless, despite the fact that such batteries are mostly "maintenance-free", you can try to restore them by returning them to their previous capacity and use them for some time.
In this article, I will explain how restore 12volt battery from UPSa at 7ah, but the method is suitable for any acid battery. But I want to warn you that these measures should not be carried out on a fully working battery, since on a working battery, capacity restoration can only be achieved by the correct charging method.
So we take the battery, in this case it is old and discharged, we pry the plastic cover with a screwdriver. Most likely it is glued to the body pointwise.
Having lifted the lid, we see six rubber caps, their task is not to maintain the battery, but to bleed the gases formed during charging and operation, but we will use them for our purposes.
We remove the caps and in each hole, using a syringe, pour 3 ml of distilled water, it should be noted that other water is not suitable for this. And distilled water can be easily found in a pharmacy or in a car market, in the most extreme case, melt water from snow or pure rainwater can come up.
After we have added water, we put the battery on charge and we will charge it using a laboratory (regulated) power supply.
We select the voltage until some values \u200b\u200bof the charging current appear. If the battery is in poor condition, then the charging current may not be observed, at first, at all.
The voltage must be increased until the charging current appears at least 10-20mA. Having achieved such values \u200b\u200bof the charging current, you need to be careful, since the current will increase over time and you will have to constantly reduce the voltage.
When the current reaches 100mA, there is no need to decrease the voltage further. And when the charge current reaches 200mA, you need to disconnect the battery for 12 hours.
Then we reconnect the battery for charging, the voltage should be such that the charging current for our 7ah battery is 600mA. Also, constantly observing, we maintain the given current for 4 hours. But we make sure that the charging voltage for a 12 volt battery is no more than 15-16 volts.
After charging, after about an hour, the battery needs to be discharged to 11 volts, this can be done using any 12 volt light bulb (for example, 15 watts).
After discharging, the battery must be charged again with 600mA. It is best to do this procedure several times, that is, several charge-discharge cycles.
Most likely, it will not be possible to return the battery to its nominal capacity, since the sulfation of the plates has already lowered its resource, and besides, there are other harmful processes taking place. But the battery can continue to be used in normal mode and the capacity will be sufficient for this.
With regard to the rapid deterioration of batteries in uninterruptible power supplies, the following reasons were noticed. Being in the same case with an uninterruptible power supply, the battery is constantly amenable to passive heating from active elements (power transistors), which, incidentally, heat up to 60-70 degrees! Continuous warming up of the battery leads to rapid evaporation of the electrolyte.
In cheap, and sometimes even some expensive UPS models, there is no charge temperature compensation, that is, the charge voltage is set at 13.8 volts, but this is permissible for 10-15 degrees, and for 25 degrees, and in the case sometimes much more, the charge voltage should be a maximum of 13.2-13.5 volts!
A good solution is to move the battery outside the case if you want to extend its life.
Also affected by the "constant small under charge" uninterruptible power supply, 13.5 volts and a current of 300mA. Such recharging leads to the fact that when the active spongy mass inside the battery ends, a reaction begins in its electrodes, which leads to the fact that the lead of the down conductors on (+) turns brown (PbO2) and on (-) becomes "spongy".
Thus, with constant overcharge, we get the destruction of down conductors and "boiling" of the electrolyte with the release of hydrogen and oxygen, which leads to an increase in the concentration of the electrolyte, which again contributes to the destruction of the electrodes. It turns out such a closed process that leads to a rapid consumption of the battery resource.
In addition, such a charge (overcharge) with a high voltage and current from which the electrolyte "boils" - converts the lead of the down conductors into powder lead oxide, which crumbles over time and can even close the plates.
With active use (frequent charging), it is recommended to add distilled water to the battery once a year.
Top up only on fully charged battery with control of both the electrolyte level and voltage. In some case, do not pour, it's better not to top up it because it cannot be taken back, because by sucking the electrolyte you deprive the battery of sulfuric acid and, as a result, the concentration changes. I think it is clear that sulfuric acid is non-volatile, therefore, in the process of "boiling" during charging, it all remains inside the battery - only hydrogen and oxygen come out.
We connect a digital voltmeter to the terminals and pour 2-3ml of distilled water into each jar with a 5ml syringe with a needle, while shining a flashlight inside to stop if the water has ceased to be absorbed - after pouring 2-3ml look into the jar - you will see how the water is quickly absorbed, and the voltage falls on the voltmeter (by a fraction of a volt). We repeat the top-up for each jar with pauses for absorption of 10-20 seconds (approximately) until you see that the "glass mats" are already wet - that is, the water is no longer absorbed.
After refilling, we inspect if there is an overflow in each battery can, wipe the entire body, install the rubber caps in place and glue the lid in place.
Since the battery after refilling shows about 50-70% charge, you need to charge it. But charging must be carried out either by an adjustable power supply unit or by an uninterruptible power supply or a standard device, but under supervision, that is, during charging, it is necessary to observe the state of the battery (you need to see the top of the battery). In the case of an uninterruptible power supply, for this you will have to make extension cords and remove the battery outside the UPSa case.
Place napkins or cellophane bags under the battery, charge up to 100% and see if the electrolyte does not leak from any jar. If suddenly this happens, stop charging and remove the smudges with a napkin. Using a napkin dipped in a soda solution, we clean the case, all the cavities and terminals where the electrolyte got into, in order to neutralize the acid.
We find the jar from where the "boil-off" occurred and see if the electrolyte is visible in the window, suck out the excess with a syringe, and then carefully and smoothly fill this electrolyte back into the fiber. It often happens that the electrolyte after refilling is not evenly absorbed and boiled up.
When recharging, we observe the battery as described above, and if the "problem" battery bank starts to "pour out" again when charging, the excess electrolyte will have to be removed from the bank.
Also, under inspection, at least 2-3 complete discharge-charge cycles should be done, if everything went well and there are no smudges, the battery does not heat up (slight heating during charging does not count), then the battery can be assembled into the case.
Well, now let's take a closer look cardinal methods of resuscitation of lead-acid batteries
All the electrolyte is drained from the battery, and the insides are washed first a couple of times with hot water, and then with a hot solution of soda (3 hours l of soda per 100 ml of water), leaving the solution in the battery for 20 minutes. The process can be repeated several times, and in the end, after thoroughly rinsing from the remnants of the soda solution, a new electrolyte is poured.
Then the battery is charged for a day, and later, within 10 days, 6 hours a day.
For car batteries with a current of up to 10 amperes and a voltage of 14-16 volts.
The second method is reverse charging, for this procedure you will need a powerful voltage source, for car batteries, for example, a welding machine, the recommended current is 80 amperes with a voltage of 20 volts.
They make a polarity reversal, that is, plus to minus and minus to plus, and for half an hour the battery is "boiled" with its native electrolyte, after which the electrolyte is drained and the battery is washed with hot water.
Then a new electrolyte is poured in and, observing the new polarity, it is charged with a current of 10-15 amperes for a day.
But the most effective way is done with chemical. substances.
The electrolyte is drained from a fully charged battery and, after repeated washing with water, an ammonia solution of Trilon B (ETHYLENEDIAMINETERAUCE Sodium) is poured containing 2 weight percent of Trilon B and 5 percent of ammonia. The process of desulfation takes place for 40 - 60 minutes, during which gas is released with small splashes. By the termination of such gassing, one can judge the completion of the process. In case of particularly strong sulfation, the ammonia solution of Trilon B should be poured again, having removed the spent one before.
At the end of the procedure, the inside of the battery is thoroughly washed several times with distilled water and a new electrolyte of the required density is poured in. The battery is charged in a standard way to the rated capacity.
Regarding the ammonia solution of Trilon B, it can be found in chemical laboratories and stored in sealed containers in a dark place.
In general, if you are interested, the composition of the electrolyte that is produced by Lighting, Electrol, Blitz, akkumulad, Phonix, Toniolyt and some others is an aqueous solution of sulfuric acid (350-450 grams per liter) with the addition of sulfate salts of magnesium, aluminum, sodium, ammonium. The Gruconnin electrolyte also contains potassium alum and copper sulfate.
After recovery, the battery can be charged in the usual way for this type (for example, in UPSe) and not allowed to discharge below 11 volts.
In many uninterruptible power supplies there is a function "battery calibration" with which you can carry out discharge-charge cycles. Having connected the load at the output of the UPS at 50% of the maximum of the UPS, we start this function and the UPS discharges the battery to 25% and then charges up to 100%
Well, in a very primitive example, charging such a battery looks like this:
The battery is supplied with a stabilized voltage of 14.5 volts, through a wirewound variable resistor of high power or through a current stabilizer.
The charge current is calculated using a simple formula: divide the battery capacity by 10, for example, for a 7ah battery it will be 700mA. And on the current stabilizer or using a variable wire resistor, you need to set the current to 700mA. Well, in the process of charging, the current will start to fall and it will be necessary to reduce the resistance of the resistor, over time the handle of the resistor will come all the way to the initial position and the resistance of the resistor will be zero. The current will further gradually decrease to zero until the voltage on the battery becomes constant - 14.5 volts. The battery is charged.
Further information on "correct" battery charging can be found
light crystals on the plates are sulfation
A separate "bank" of the battery battery was constantly undercharged and, as a result, covered with sulfates, its internal resistance grew with each deep cycle, so that, during charging, it began to "boil" before anyone else, due to the loss of capacity and the removal of electrolyte into insoluble sulfates.
The plus plates and their grilles have turned into a powder in consistency, as a result of constant recharging by an uninterruptible power supply in stand-by mode.
Lead acid batteries, except for cars, motorcycles and various household appliances, where they are not found in flashlights and watches, and even in the smallest electronics. And if you got into your hands such a "non-working" lead-acid battery without identification marks and you do not know what voltage it should give out in working condition. This can be easily recognized by the number of cans in the battery. Find the protective cover on the battery case and remove it. You will see the gas bleed caps. by their number it will become clear how many "cans" this battery is.
1 can - 2 volts (fully charged - 2.17 volts), that is, if the cap is 2, then the battery is 4 volts.
A fully discharged battery bank must be at least 1.8 volts, you cannot discharge below!
Well, in the end I will give a small idea, for those who do not have enough funds to buy new batteries. Find companies in your city that are engaged in computer equipment and UPSs (uninterruptible power supplies for boilers, batteries for alarm systems), agree with them so that they do not throw out old batteries from uninterruptible power supplies, but give you possibly at a symbolic price.
Practice shows that half of AGM (gel) batteries can be restored, if not up to 100%, then up to 80-90% for sure! And that's another couple of years of excellent battery life in your device.
He restored the car battery by polarity reversals, which came out of this after the battery was idle. I tried this method and now I can say for sure: it works. But if we take into account which batteries passed through my hands and after disassembly I saw a not rosy picture, I will add it is not suitable for all batteries, and in some cases this method is even very dangerous!
The thing is that any batteries have plate wear, no one knows how much wear is strong, since batteries are usually not transparent and even less collapsible. This means that you also cannot see how much wear of the plates or how much debris fell to the bottom of the can.
Accordingly, when the battery polarity is reversed, a strong reaction occurs inside the battery cells, which is accompanied by a gradual dissolution of sulfate. In this case, the solution in the jars begins to move strongly due to the reaction. Well, it does not boil, but a chemical reaction is going on with the release of hydrogen. If at the bottom of the battery there is slag from crumbled plates, the worst thing with such a reaction is if the slag raised from the bottom between the plates shorts. This will be the most epic latest battery action.
Therefore, it is necessary to discharge the battery as much as possible before polarity, then charge it with a current at which the battery will release the minimum amount of hydrogen. Ideal if there are a lot of very small bubbles. In case of bubbling, the current must be reduced. It is effective to charge a reversible 55Ah battery with a current of 2A for about 26-29 hours, it took me about this time to bring the battery to a voltage of 13.9 Volts. Since with reverse polarity, the voltage is lower due to the difference between plates A and K, and due to the fact that the contacts for the terminals are different, I began to reverse the battery polarity back.
This is where the difficulty arose. This is a strong release of hydrogen and strong heating of the battery plates, due to the fact that the density and charge in the banks are different. DC discharge of cans is a heavy load on the battery and on the charger itself. The following method helped me.
I impulsely connected and disconnected the charger. Pulse frequency 2 sec charge, 2 sec rest of the charger and after such a connection, the reaction in the banks decreased, and the battery quickly changed polarity, while the charge current was, do not believe 10A, the thing is that for the charger even at 6 volts of charge voltage, the resistance The battery at 0 -1 volts was tantamount to a short circuit.
Because of what the battery is heating up: because of the loss in capacity of problem banks and because non-problem banks resist those that surrendered, this is just like a war between good and evil. 🙂 War cannot be won without constant attack. But a huge plus of this war lies in the fact that troubled banks at this very moment begin to get rid of sulfate as much as possible.
In case of reverse polarity reversal, it is imperative to place the battery in the coldest water possible, thereby the chemical processes will be less dangerous.
Why do I recommend changing the electrolyte, the thing is that after I charged the battery, the density went off scale for 1.32, at any charge current, the battery began to boil. the charge current did not decrease. At first, I thought that there was a short circuit of the plates, but the dregs in the cans haunted me and I decided to risk changing it.
I warn you need to bring to the required density not with the required electrolyte, but with a dis. water, since the plates are saturated with electrolyte and after pouring, for example, 1.27, you will get a density of 1.35, and the plates can simply be short!
In general, I poured the solution and lo and behold, the battery stopped boiling, stopped heating, and the current after charging to 14.9 volts dropped to 500mA - this is normal.
And only after that I breathed a sigh of relief. The next step was to check the battery for capacity and self-discharge. Previously, my battery went to zero on the fourth day, the last time I barely started at the beginning of the third.
