How to open a maintenance-free battery by yourself
Long gone are the days when you just plugged a battery into a charger and left it on overnight. For example, a fully discharged battery with a capacity of 50 ampere-hours should be charged at the current strength of 5 amperes for ten hours. The charging must be done with the caps or plugs removed. You can’t charge the battery too fast either. This can lead to overheating or even boiling of the electrolyte.
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In the 90’s the development of battery manufacturing has stepped forward. Whereas previous batteries required monitoring of the electrolyte level, according to manufacturers, there is no need for this on today’s models. Manufacturers call such batteries maintenance-free, according to them, they do not require control of the electrolyte. However, this is far from being true, these batteries still require maintenance.
Know your battery’s charging time
Batteries without access to the banks are relatively new and widespread. Check the level of charge with a hydrometer or “sight glass.
In most cases, lack of maintenance of such batteries is fraught with battery failure.
The main disadvantages of such batteries include:
- Difficulties with electrolyte level control;
- Inability to control the density of the electrolyte;
- The need for flawless operation of the machine’s power grid.
Some types of batteries have minimum and maximum electrolyte level markings.
What tools do you need for opening
To gain access to the fill holes, even if they are filled at the factory to the level of the case surface, it is necessary to remove the cover from the battery. How to open a battery cover? If it is on the grooves, then carefully unfasten the fasteners and remove the cell. You may need a flat-blade screwdriver.
A hot pressed part will not come off easily. During its disassembly there is a high probability of breaking the part. That’s why we do not recommend removing this type of cell. However you may try to break the battery using an awl, screwdriver, or drill. You will not remove the cover completely, but you can make holes for further operations.
How to open a maintenance free battery
There are not many ways to open a closed power supply, and they depend on the goal. If you need a lead (for hunting or fishing), then you can not worry about how to open the battery, and just break its case.
In order to extend the life of the battery, you need to make holes that will give access to the banks.
- Remove the stickers from the surface of the battery.
- Carefully inspect the case. Since the battery is sealed lead-acid battery was poured in the factory, there is still a stamping of the plugs.
- Take an awl, screwdriver or drill and carefully make holes in the place of pours.
This simple procedure demands some accuracy but allows you to restore the working capacity of the existing battery instead of buying a new one.
How to turn a maintenance-free battery into a serviceable one
The time comes and the car owner is no longer satisfied with the characteristics of the battery. If you have a closed type battery, you should not throw it away and buy a new one. You can make it serviceable if you open the lid in the way we described above. This will allow you to perform a number of procedures necessary to maintain the performance of the power source.
The ability to check and change the electrolyte level is one of the signs of a serviceable battery. Closed cell batteries are equipped with an indicator that allows you to see the level of electrolyte. Some casings are made of translucent materials or are characterized by markings that help keep track of the amount of mortar in all the jars. The electrolyte level may be checked using a special tube or syringe placed in the holes provided in the lid. A normal amount of solution relates to 10 to 12 millimeters of liquid above the plates.
Do not forget that not only the acid level but also the density is an important determinant of battery performance. To obtain a reading of the density of the solution is to use a areometer. Take a syringe, insert it through the hole in the lid, and draw the electrolyte from the can. Pour it into the areometer and look at the reading. Too low a density (less than 1.22 g/cm3 at up to 6) will not allow the battery to function properly and indicates that the amount of electrolyte is low and must be replenished. If the density or level of the solution is too low, it is necessary to top up with distilled water.
Read more about the process of adjusting the density in our article: How to use a areometer correctly.
Checking electrolyte level with a thin tube.
Please note, the excessive concentration of electrolyte leads to unfortunate consequences. sulfation and destruction of the plates.
This picture shows the values of the density of the electrolyte under different conditions.
After you have finished topping up with water or acid solution, it is necessary to cover the holes in the lid with sealant.
Is it safe to say that a maintenance-free battery can be made into a serviceable one?? Of course, a sealed battery can be rebuilt! If the purpose of battery opening is to get lead for fishing or hunting, then with a few precautions you can easily manage with just a hammer.
The “western” motorists are used to going to the service stations for every little detail. service, while domestic car owners try to repair the car themselves. One machine unit that needs maintenance is the battery. It requires access to the electrolyte for maintenance. Modern batteries are divided into batteries with access and without access to the electrolyte.
What you will need
Disassembling the battery case
The case of any battery is demountable. Consists of two parts, which are connected by small screws or glue. In the first case it’s easy: just unscrew the screws and separate the parts. If the case is glued, you will have to work hard to accurately get to the cells without damaging them. First you need to stick the blade of a knife at any point on the joint between the parts, then insert something sharp there, such as a screwdriver. In this way it is possible to wedge a separate section. Then you need to carefully go over the entire perimeter with a blade to separate the glued parts. The case is disassembled. After repairing it will need to be glued again.
Find the fault
When you get to the battery cells, you will see that they are just jars connected in series. So, one faulty cell can be the cause of poor operation of an electric screwdriver. An important step in repairing the battery of an electric screwdriver with your own hands is to find that weak link.
The test must be done on a fully charged battery. It is necessary to remove all cells from the case and for convenience lay them out on the table so that there was free access to the connection pins. Use the stylus of the multimeter to measure the voltage at each bank, and be sure to record the readings. For convenience you can draw a diagram on a sheet of paper and record the readings there. It is possible to mark them directly on the cells.
For the nickel cadmium batteries the voltage of each cell must be between 1.2 and 1.4 V, and between 3.6 and 3.8 V for the lithium ion batteries.
After measuring the voltage, the battery is assembled and operated with an electric screwdriver until the loss of power. Then they are disassembled again and measured and recorded again. The cells that had the lowest voltage values during the first measurement have the highest losses. It is worth noting that a significant difference in the voltage of the banks is considered 0.5. 0.7 V. Such elements and should be replaced.
For your information! When repairing an electric screwdriver battery with your own hands, replacing the cells is considered more effective than repairing them. The thing is that the restored banks will not last long, and soon they will have to be replaced anyway. So it’s better not to do double work and immediately make a replacement.
Replacing damaged cells
At the upcoming self-repair of the battery of an electric screwdriver in many users the question arises, where to get new banks. You can find an old battery, for example, from friends or visitors of thematic forums. Use it as a donor and take away from it working cells. You can buy cells separately. They are sold in radio and electrical stores or on private ads sites. Some craftsmen order batteries from Chinese sites. Agree that it is not that much money compared to buying a new battery.
Tip: When selecting, make sure the new cells are the same size and current rating as the cells you are replacing.
The process of replacing damaged cells is quite simple. It is not difficult for those who have had to deal with soldering. First you should carefully cut off the connecting plate and remove the defective can. Try to keep this plate to attach the new cell. When installing a new bank, make sure the plus and minus sides are positioned correctly. When connecting in series, arrange the cell so that the minus of the previous one goes to the plus of the new one. You can securely hold the jars together with electrical tape around the perimeter of the jar.
Warning! Try not to overheat parts and work fast when soldering. It is important to observe this rule, so as not to overheat the battery. Otherwise there is a risk of damaging it.
Charging and discharging the repaired battery
After repairing the electric screwdriver battery, the potentials on the cells will be different, so they must be equalized. Leave the assembled battery to charge for a long time, e.g. over night. Then leave it to cool down for about 24 hours. After that check all cell voltages. If all processes are done correctly, the readings on each bank will be the same, such as 1.2. 1.3 V.
The next step is to fully discharge the battery. Work with the electric screwdriver until the charge is gone. After that fully charge the cell. Repeat the charging / discharging cycle 2 more times. This will help prolong the life of the battery that has been brought back to life.
Say that it is not necessary to take this article as an exact guide in repairing the battery of an electric screwdriver with your own hands. It is just one way to bring a battery cell back to life. If the topic interests you, study it on tool forums, talk to craftsmen who share their experience, ask them questions. Try to repeat their experience. you can probably do just as well.
Electric screwdriver battery recovery after a deep discharge
I work in the service center for repair of electric and gasoline tools, power equipment. From time to time we receive cordless tools for repair. Both customer and pre-trade. with the reason for the appeal: “The battery is not working/charging”. The prerequisites for this defect are usually:
Today I want to focus on the last option. Deep discharge occurs when a discharged battery has been stored for a long time, for example, in a closet in your home, or in a cold room. the effect is faster (I’m sure many are familiar with the situation when the battery charge of the smartphone melts before their eyes in the cold). From our wholesale customers, it also happens that a brand new tool arrives with this problem. often than not, it turns out that they store tools all winter in unheated warehouses.
The root of the problem is that even when the battery is not being used. it loses its charge, even if just a little. The charge level eventually drops below the minimum allowable value, and at a certain point the protection module built into the charger control board/AKB or 18650 battery protection module refuses to accept the charge, believing that there is some problem with the battery (short circuit for example). The protection module is essential for your safety. As a result. The battery does not pick up the charge, and empty it, respectively, also does not work. This is true for the entire family of lithium-ion batteries, including.h smartphone batteries. The worst thing about deep discharge. the battery inevitably and irreversibly loses its capacity, so keep your cordless tool at least somewhat charged.
Deeply discharged battery/battery. is the least of all possible evils and “treated by” very simple: bypass the control board of the battery / charger need to bypass the capacitance directly and charge them to a level where the board will consider the level of charge in the common circuit of batteries and starts to charge the battery. I suggest we move on to practice)
Yesterday we received a pre-sale cordless electric screwdriver with 18V lithium-ion batteries, came in from a wholesale customer’s store, with two non-functional batteries. The problem was identified when selling. Took it home for the weekend, specifically to write the post:
Both batteries are discharged, the indication does not work, the charger does not pick up. Voltage. less than the smallest:
Necessary minimum (or maximum). Multitester, a Phillips/TORX screwdriver and a dodgy cable. The tricky cable is made of any unnecessary ordinary USB cable and a 62 Ohm resistor (the resistor lowers the current and resistance for the most painless charging of the battery). The USB cable has 4 wires: the resistor is connected to the red VBUS 5V, the black GND is not touched. DATE and DATE we don’t need, we can remove. The smart cable can be powered from any smart phone power adapter, PC USB socket, even the TV USB socket. In general, any USB socket with 5V and from 400mA:
And now we are equipped with everything we need. Hook the toothy crocodiles to the multimeter probes, set the mode “20VDC”:
Charge the capacitance. It takes less than a minute for an empty battery to reach ~1.5V. If, before and after recharging, the battery is not gaining a charge and shows 0. The battery has gone into protection. In our case all capacitances are gaining, i.e.к. the electric screwdriver is new, it has not been used. From experience, on this particular model, it is sufficient to charge each capacity to ~1.5-1.6V. It can be different depending on the board.е. of the manufacturer and model. To answer your question “Why alligator probes and not magnets?”. so the process is better controlled. Voltages on the capacitors should be the same after charging. Although the board does equalize the charge in the capacitors, but from manufacturer to manufacturer it does so with varying success. Bottom line: if the capacitors have different voltages. When reaching a level of charge, for example, 4.2V on one capacitance and 3.6V on the other capacitance. the board will stop charging once the maximum voltage is reached on one of the capacitors. As a result, we get a battery with 15-16V on board, it will suffice for a small pinch of screws, and then have to charge again. We charge with any option you like (remember that the skirt on the heat shrink. where plus, where there is no skirt. minus):