Recently, all inexpensive radio-controlled models began to be equipped with Ni-Cd batteries (nickel-cadmium batteries), or rather, assemblies of these batteries. Batteries of this type have a low market value and there are a number of reasons for this.
Relatively simple and cheap manufacturing technology
Have a memory effect
Small number of recharges
Small specific capacity
Sooner or later, your favorite toy stops turning on, the battery becomes unusable, and the question arises where to find a new one. But where to find the right size, and most importantly with the same type of battery connector ?!
You don't have to look for anything if you have a soldering iron, a pair of wires, a heat shrink tubing, and 30 minutes of free time.
So, let's say you have a toy powered by a 7.2 V Ni-Mh or Ni-Cd rechargeable battery, 400 ma / h. Naturally, we want not only to bring the toy back to life, but also to extend the playing time on one charge. Therefore, we will increase the capacity of new batteries several times!
By turning the old battery in your hands and cutting its shell, you can easily make sure that it is assembled from conventional AA-grade AA batteries by the serial connection method.
Therefore, we need, in our example, this:
6 rechargeable batteries Ni-Mh class AA, each battery 1.2V, respectively, to obtain 7.2V \u003d 1.2V * 6, The same capacity!
· Heat-shrink tubing
Soldering equipment: soldering iron, flux, solder
File / skin
Copper stranded wire about
You may have noticed that the batteries in the old battery are not soldered. And this was not done in vain, because with strong heating, the battery can be damaged, but, as they say, "everything is good in moderation." We will connect the batteries by soldering, but using a certain technology.
In order for the solder to quickly "stick" to the contact surface of the battery, first clean the surface with a file. When processing with a file, irregularities and scratches are also created which will create conditions for reliable contact.
Personally, I use ordinary rosin or soldering fat as a flux, and ordinary tin-lead solder, the temperature of the soldering iron is 450 degrees.
We will tin the contact pad. If the solder does not "stick" it is not necessary to heat up the battery pad for a long time, this can lead to its failure. In this case, add flux and solder and try again.
I do not recommend using insulated wires to connect the battery, because they will greatly change the size of the battery, in some cases this is a very important factor. Therefore, I usually strip the insulation and make a kind of flat connecting plates by tinning the bare wire.
Since we tinned the contact pads of the battery in advance, it will not be difficult for us to solder the connecting plate.
We connect the battery in series, that is, "+ " one battery is connected to "- " another, and so on. The positive contact of the first and the negative contact of the latter, respectively, will give a total output voltage equal to 7.2 Volts.
Having connected all the necessary wires, including the charging connector, we put the assembly in a heat-shrinkable tube and heat it (you can use a regular hair dryer).
Let's summarize. You were the owner of a weak battery with a 7.2V supply voltage, 400ma / h capacity, which was based on 6 rechargeable Ni-Cd batteries. Taking the connector from the old "dead" battery and doing all the work described above, we got: a battery with a capacity of 1800 ma / h, supplying voltage 7.2 volts, Ni-Mh without memory effect.
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In this video tutorial, we will show you how to make a battery yourself. To make it, we need a small container with a lid, soda, water, and a charger.
Pour water into a jar of vitamin, pour 1.5 teaspoons of baking soda into it. Mix the solution well. Let's clean the welding electrode from the coating. We cut off two pieces of 7 cm from the electrode. We bend the ends of these blanks. We insert these blanks into the holes in the lid and twist it into the bottle.
We connect the charger to the ends of the battery. We charge the battery for 10 minutes and check the operation of the homemade battery. The estimated voltage at the output is 1.5-2.5 volts. This power supply will be enough for 3 hours charging for 20 minutes of LED glow. To keep your battery from swelling, do not make it sealed.
Another way to make a homemade battery
Homemade rechargeable battery from scrap materials with a minimum of tools. Imagine a situation when there are no necessary parts nearby, more precisely, there is a minimum, but you are in the field, when there is no variety. We will have to experimentally artificially limit ourselves to the choice of materials.
Let's take copper wire for lack of copper in the plates. Remove the insulation with fire. We cut the scrap of galvanized iron into identical plates. Insulated wires for connecting the circuit. You can immediately take a conductive wire without insulation. You also need to find a plastic bottle, any dielectric will do. Conductive liquid solution (hydrochloric or acidic, alkaline). Disposable cups.
To begin with, we twist the wire annealed on fire to increase the area into a cylinder. From galvanized, we cut identical plates according to the template and roll them into cylinders (we bend the corner to clamp the contact wire in it).
From a plastic bottle, we cut the cushioning material, which will be located between the copper and galvanized. We collect the battery cells, fix one end of the wire on a thread, the other on zinc and two single ones. One with copper - positive and with zinc - negative.
We collect the battery in a serial circuit. First, let's try to pour a solution saturated with salt. In the field, any saline solution, urine, and more will do. The voltage is 7.74 volts. Let's replace the saline solution with an acidic one; table vinegar was used in the experiment. In the field, sour wine, sorrel infusion, cranberry juice and more are suitable for ours. Voltage 8.05 volts.
Let's replace it with an alkaline solution, baking soda in nature, you can try to replace it with ash placed in water (lye), but you need to experiment to check. Voltage 9.65 volts.
So to summarize: on average, out of 10 elements we get 8 volts, one glass is equal to 1.25 volts. To reduce the voltage for charging the phone (5.5 volts), remove two cups, the procedure takes 20 seconds. Or increase to 4.5 volts by adding 5 cups. This is how you can make a battery when there is no way to buy it with your own hands.
In this article, a DIY master will walk us through all the stages of battery assembly, from material selection to final assembly. Radio-controlled toys, laptop batteries, medical devices, e-bikes, and even electric cars use 18650 batteries.
18650 battery (18 * 65mm) is the size of lithium ion battery. For comparison, conventional AA batteries have a size of 14 * 50 mm. Specifically, the author made this assembly to replace a lead-acid battery in a homemade product he had made earlier.
Video:
Tools and materials:
- ;
- ;
- ;
- ;
-Switch;
-Connector;
- ;
-Screws 3M x 10mm;
-Apparatus for spot contact welding;
-3D printer;
-Stripper (tool for stripping insulation);
-Hairdryer;
-Multimeter;
-Charger for lithium-ion batteries;
-Protective glasses;
-Dielectric gloves;
Some tools can be replaced with more affordable ones.
Step one: choosing batteries
The first step is to choose the right batteries. There are various batteries on the market from $ 1 to $ 10. According to the author, the best batteries are from Panasonic, Samsung, Sanyo and LG. For the price they are more expensive than others, but have proven to be good quality and characteristics.
The author does not recommend buying batteries with the names Ultrafire, Surefire and Trustfire. These are batteries that did not pass quality control at the factory and were bought at a bargain price and repackaged under a new name. As a rule, such batteries do not have the declared capacity and there is a risk of fire during charge-discharge.
For his homemade product, the master used Panasonic batteries with a capacity of 3400 mAh.
Step two: choosing a nickel strip
The battery needs nickel strips to connect. There are two products on the market: nickel plated metal and nickel strips. The author recommends using nickel strips. They are more expensive, but have low resistance and therefore heat less, which affects the battery life.
Step three: spot welding or brazing
There are two ways to connect batteries, soldering and spot welding. The best choice for spot welding. The battery does not overheat during spot welding. But the welding machine (like the author's) costs approx. 12 tr. in a foreign online store and approx. 20 tr. in the Russian online store. The author himself uses welding, but he prepared several recommendations for soldering.
When soldering, keep the contact of the soldering iron with the battery to a minimum. It is better to use a powerful soldering iron (from 80 W) and quickly solder than to warm up the place of the solder.
Step four: check the batteries
Before connecting the batteries, you need to check each of them separately. The battery voltage should be approximately the same. New quality batteries have a voltage of 3.5V - 3.7V. Such batteries can be connected, but it is better to equalize the voltage using a charger. Used batteries will have an even greater voltage difference.
Step five: battery calculation
For the project, the master needs a battery with a voltage of 11.1 V and a capacity of 17000 mAh.
18650 battery capacity is 3400mAh. When five batteries are connected in parallel, we get a capacity of 17000 mAh. Designate such a compound P, in this case 5P
One battery has a voltage of 3.7 V. To get 11.1 V, three batteries must be connected in series. The designation is S, in this case 3S.
So, to obtain the desired parameters, you need three sections, each consisting of five parallel-connected batteries, to be connected in series. 3S5P package.
Step six: battery assembly
The master uses special plastic cells to assemble the battery. Plastic cells have a number of advantages over joining them, for example, using a glue gun.
1.Easy assembly of any quantity.
2. There is space between the batteries for ventilation.
3.Vibration and shock resistance.
Collects two cells 3 * 5. Installs, in the cell, the first pack of 5S batteries with plus up, the next five with minus up and the last five batteries with plus up again (see photo).
Sets the second cell on top.
Step seven: welding
Cuts off four nickel strips for parallel connection, with a 10 mm margin. Cuts ten strips for serial connection.
Places a long strip on the + contacts of the first (when turned over, it will remain the first) of the parallel 5P cell. Welds the strip. Welds strips with one end to + third cell with the other to - second. Welds a long strip to the + third cell (over the plates). Flips the block. It welds the plates from the reverse side, taking into account that now we connect the third in parallel, and the first and second sections in parallel-series (considering that it was turned over).
Step eight: BMS (Battery Management System)
First, let's understand a little what a BMS is.
BMS (Battery Management System) is an electronic board that is placed on a battery in order to control its charging / discharging process, monitor the condition of the battery and its elements, control temperature, the number of charge / discharge cycles, and protect the battery components. The control and balancing system provides individual control of the voltage and resistance of each battery element, distributes currents between the battery components during the charging process, monitors the discharge current, determines the loss of capacity from imbalance, and guarantees safe connection / disconnection of the load.
Based on the received data, the BMS balances the charge of the cells, protects the battery from short circuit, overcurrent, overcharge, overdischarge (high and excessively low voltage of each cell), overheating and hypothermia. The functionality of the BMS allows not only to improve the operation of the batteries, but also to maximize their service life.
Important parameters of the board are the number of cells in a row, in this case 3S, and the maximum discharge current, in this case 25 A. For this project, the master used board with the following parameters:
Model: HX-3S-FL25A-A
Overvoltage range: 4.25 ~ 4.35V ± 0.05V
Discharge voltage range: 2.3 ~ 3.0V ± 0.05V
Maximum working current: 0 ~ 25A
Working temperature: -40 ℃ ~ + 50 ℃
Solders the board to the ends of the battery according to the diagram.
Greetings friends. Today I will tell you about the most effective way to restore the capacity of a lead acid battery.
During the period of even the most correct operation, the battery loses its capacity every day. And at one point, its charge is not enough to start the car engine. This example is aggravated with the arrival of cold weather.
Naturally, the car enthusiast puts the battery on charge and after a while he sees that the battery is not charging, and the charging voltage is normal - 14.4-14.7 V or higher (12.6 without a charger).
Then, if there is a load plug, it is checked and it turns out that under load the voltage sags greatly. Everything indicates a loss of capacity by the battery. The reason for this is the sulfation of the plates.
Usually, with proper use, this happens after about 5 years. This is a very good indicator. And then there is a way out - buy a new battery. But, if you want to save money (since batteries are not cheap now), and extend the battery life by another couple of years, then you need to service it. And not a simple one, but a special one that can reanimate the battery.
What batteries can be recovered?
This method is suitable for batteries that have not been subject to serious current or mechanical damage during their operation. And they fell into disrepair as a result of temporary, natural sulfation.This method is not suitable for batteries that have internal flaking of the plates, there is an internal closure of the cans, there is swelling or other mechanical damage.
The method is excellent for desulfation of plates and is popularly called the battery “polarity reversal” method.
I will divide the battery recovery into three steps.
Battery recovery process
Stage one: preparation
The first thing is not necessary, but you need to do it to clean the surface of the battery from any contamination. Wash the entire surface with detergent.Further, visually make sure that there is no damage to the case, in the absence of bulges and bulges on the sides.
Second, open all the cans' caps and make sure there is electrolyte. If one of the cans does not have it, then you need to make sure that there are no cracks on the case.
Then, using a flashlight, examine the plates inside - there should be no shattering. Here, just for one thing, you can clearly see sulfation - a white coating on the plates.
If everything is in order, add distilled water to each jar to the level. It will not be superfluous to measure the density of the electrolyte in each compartment.
Stage two: the classic recovery method
Before proceeding to reversing the battery polarity, it is necessary to test the usual recovery method, which has already become classic.Step one: we charge the battery to a full charge of 14.4 V.
Step two: With a halogen lamp or other load, we discharge the battery to 10.6 V (the voltage is measured under the same load).
We repeat the cycle of these two steps 3 times and charge the battery to full. We check the capacity with a load fork or a starter during machine operation. If the battery recovers - good - we continue to operate. If not, or not enough, then proceed to the third stage.
Stage three: polarity reversal of the battery
This battery recovery method is the most effective of all. And reanimates the battery in almost 90% of cases.Step one: we hang a load in the form of a halogen lamp on the battery, and discharge the battery to zero. The lamp will go out in about a day (it all depends on the initial battery capacity). We leave the battery with the lamp connected for another 2-3 days in order to finally discharge the residues.
Step two: reverse charging the battery. We connect the charger in reverse: plus to minus, and minus to plus. In order not to spoil your charger (or so that the short circuit protection does not work), we connect the same halogen lamp in series with the batteries. And we charge the battery in reverse polarity. After the voltage has risen to 5-6 volts, the lamp can be excluded from the circuit. It is advisable to set the charge current to 5 percent of the battery capacity. That is, if the capacity is 60 ampere-hours, then we set the charge current in the opposite direction to 3 amperes. At this time, all cans with electrolyte begin to actively boil and hiss — this is normal, since the reverse process is going on.
We charge for about a day, until a voltage of 12-14 V appears. As a result, you have a fully charged battery, which has a minus at the plus output and a plus on the minus.
Step three: again completely discharge the battery with a halogen lamp for a couple of days. Then we make the correct charge plus to plus, minus to minus. We charge at full up to 14.4 V.
This completes all the actions.
Battery recovery result
Usually, the result helps to increase the battery capacity to 70-100% of the factory one, of course there are exceptions.Specifically, in my case, I managed to raise the capacity by 95% - which is an excellent result. The white sulphate coating disappeared from the plates, and they turned black like a new battery. The electrolyte has become more transparent and pure.
Battery recovery video
I recommend that you watch a video, where a completely "dead" battery, which is about 10 years old, is being restored.First, there is a "swing" with a change in the polarity of the power supply, and almost at the very end, a full polarity reversal cycle is already given.
A battery or galvanic cell is a chemical source of electrical current. All batteries sold in stores are essentially the same design. They use two electrodes of different composition. The main element for the negative terminal (anode) of salt and alkaline batteries is zinc, and for their positive (cathode) - manganese. The cathode of lithium batteries is made from lithium, and a variety of materials are used for the anode.
An electrolyte is located between the electrodes of the batteries. Its composition is different: for salt batteries with the lowest resource, ammonium chloride is used. Potassium hydroxide is used to make alkaline batteries, and an organic electrolyte is used in lithium batteries.
When the electrolyte interacts with the anode, an excess of electrons is formed near it, which creates a potential difference between the electrodes. When the electrical circuit is closed, the number of electrons is constantly replenished due to a chemical reaction, and the battery maintains the current flow through the load. In this case, the anode material gradually corrodes and degrades. When it is fully depleted, the battery life is exhausted.
Despite the fact that the composition of the batteries is balanced by the manufacturers to ensure their long and stable operation, you can make the battery yourself. Let's consider several ways how you can make a battery yourself.
Method one: lemon battery
This homemade battery will use the citric acid electrolyte found in lemon pulp. For the electrodes, take copper and iron wires, nails or pins. A copper electrode will be positive and an iron electrode negative.
The lemon needs to be cut in half across. For greater stability, the halves are placed in small containers (glasses or glasses). It is necessary to connect the wires to the electrodes and immerse them in the lemon at a distance of 0.5 - 1 cm.
Now you need to take a multimeter and measure the voltage across the resulting galvanic cell. If it is not enough, then you will also need to make several identical lemon batteries with your own hands and connect them in series using the same wires.
Method two: a can of electrolyte
To assemble a device with your own hands, similar in design to the first battery in the world, you will need a glass jar or glass. For the electrode material we use zinc or aluminum (anode) and copper (cathode). To increase the efficiency of the element, their area should be as large as possible. It will be better to solder the wires, but the wire will have to be riveted or bolted to the aluminum electrode, since it is difficult to solder it.
The electrodes are immersed inside the can so that they do not come into contact with each other, and their ends are above the level of the can. Better to secure them by installing a spacer or slotted cover.
For the electrolyte, we use an aqueous solution of ammonia (50 g per 100 ml of water). An aqueous solution of ammonia (ammonia) is not the ammonia used for our experience. Ammonium chloride (ammonium chloride) is an odorless white powder used in soldering as a flux or fertilizer.
The second option for preparing the electrolyte is to make a 20% sulfuric acid solution. In this case, you need to pour acid into water, and in no case vice versa. Otherwise, the water will instantly boil and splashes together with the acid will fall on clothes, face and eyes.
When working with concentrated acids, it is recommended to wear protective goggles and chemical resistant gloves. Before making a battery using sulfuric acid, it is worthwhile to study in more detail the safety rules when working with aggressive substances.
It remains to pour the resulting solution into the jar so that at least 2 mm of free space remains to the edges of the vessel. Then, using a tester, select the required number of cans.
A self-assembled battery is similar in composition to a salt battery, as it contains ammonium chloride and zinc.
Method three: copper coins
The ingredients for making such a battery with your own hands are:
- copper coins;
- aluminium foil;
- thick cardboard;
- table vinegar;
- wires.
It is easy to guess that the electrodes will be copper and aluminum, and an aqueous solution of acetic acid is used as an electrolyte.
Coins first need to be cleaned of oxides. To do this, they will need to be briefly dipped in vinegar. Then we make circles from cardboard and foil to the size of coins, using one of them as a template. We cut out the circles with scissors, put the cardboard ones in vinegar for a while: they should be saturated with electrolyte.
Then we lay out a column from the ingredients: first a coin, then a cardboard circle, a foil circle, a coin again, and so on, until the material dries up. The end element should again be a copper coin. You can solder wires to the outermost coins. If you don't want to solder, then the wires are applied to them, and the whole structure is tightly wrapped with adhesive tape.
During the operation of this self-assembled battery, the coins will become completely unusable, so you should not use numismatic material of cultural and material value.
Method four: a battery in a beer can
The anode of the battery is the aluminum body of the beer can. The cathode is a graphite rod.
Additionally you will need:
- a piece of polystyrene more than 1 cm thick;
- coal chips or dust (you can use what is left from the fire);
- water and common table salt;
- wax or paraffin (candles can be used).
Cut off the top of the can. Then make a foam circle to fit the bottom of the can and insert it inside, having previously made a hole in the middle for the graphite rod. The rod itself is inserted into the jar strictly in the center, the cavity between it and the walls is filled with coal chips. Then an aqueous solution of salt is prepared (for 500 ml of water 3 tablespoons) and poured into a jar. To prevent the solution from spilling out, the edges of the jar are filled with wax or paraffin.
You can use clothespins to connect the wires to the graphite rods.
Method five: potatoes, salt and toothpaste
This battery is disposable. It is useful for starting a fire by short-circuiting the wires to produce a spark.
To create a potato lighter you will need:
- large potato;
- two copper wires insulated;
- toothpicks or thin chips similar to them;
- salt;
- toothpaste.
We cut the potato in half so that the cutting plane has the largest possible area. In one half, with a knife or spoon, select a depression where we pour salt and add toothpaste. We mix them together until a homogeneous mass is obtained. The amount of "electrolyte" should be flush with the edges of the recess.
In the other half, which will be the top, we pierce two holes at some distance from each other in such a way that they both fall into the depression with the electrolyte when assembling the "battery". We insert wires into the hole, previously stripped of insulation by about a centimeter. We put the halves together so that the ends of the wires are dipped into the electrolyte. We fasten the halves together with toothpicks.
We wait for about five minutes, after that, by shorting the wires together, you can strike a spark and make a fire.
All the methods described above are not a complete replacement for a battery purchased at a store. The voltage on homemade cells can fluctuate and cannot be accurately adjusted. You won't be able to use them for a long time either. But somewhere in the wilderness, in the absence of electricity, everyone is quite capable of assembling a battery for a mobile phone or an LED light bulb with their own hands. Naturally, with the appropriate materials at hand.