A device necessary to determine the degree of charge and serviceability of an automobile battery. With its help, you can determine the voltage level of the battery at idle and under load. A do-it-yourself battery load plug can also be made - with certain skills and abilities.
What is a load fork
Standard load plugs are often manufactured as handle voltmeters with the ability to connect a load in parallel with the voltmeter itself. The load is carried out in the form of a spiral, which has connection functions different ways. There are plugs that can be brought to the battery banks, there are devices for testing 12-volt batteries - when the load is connected through a nut.
Modern plugs are equipped with a liquid crystal display and, as a rule, have several load modes. For testing conventional batteries, a plug with a current load of 100 A will suffice.
Any load fork is one of the elements of a closed electrical circuit, which has a fairly large power rating. The simplest version of such a device consists of a voltmeter, a wire resistor and two clamps.
There are many options on how to make a load fork yourself. As they say, "there would be enough junk in the garage." Because often it is made from improvised means, based on the fact that it is used infrequently, and it is not at all necessary to buy it on purpose. The main thing that circuit diagram was built correctly, in accordance with simple calculations.
The easiest way to make a load fork
In order to make the simplest plug and immediately take the necessary readings, you will need the following available tools and actions:
- Any spiral. You can take a solid spiral from an old electric stove lying around in the garage.
- The spiral should be rolled up in several layers (wire cores), having achieved a resistance index 0.1-0.15 ohm.
- Need to take it myself battery(with voltage up to 15 V), car light bulb (for example, remove it from the turn signals, with a power of 21 W). Such homemade resistance can either be soldered or secured with a screw and nut. You will also need multimeter with a current range of 10 amps.
- All chain going And connected in series .
- Then the clamps are brought out to the battery terminals .
- The multimeter gives a reading of the current flowing through the circuit. The usual indicator, in this case, is ± 1.78 A.
- Now remove the multimeter and again turn on the whole circuit .
- We take with it the voltage readings on the spiral , which is retinue in several layers. Here the indicator will be already in millivolts, about 197 mV.
- We calculate the required resistance according to Ohm's law - 0.197: 1.78= 0.11 ohm.
Thus, the resistance of our homemade resistor is 0.11 ohms. Now you need to connect it to the battery for 5-10 seconds with a multimeter connected to it, which will measure voltage readings in the 20 volt constant range. We take readings, record them. A do-it-yourself load fork works well if the chain is assembled correctly.
The second way is just as easy.
This will require "spare parts" from old cars.
If they are available in the garage, then you can make a homemade load fork like this:
- take a mass breaker from an old car, for example, from a GAZelle;
- remove two dopresistors for the fan “to the light” from the garage;
- add clamps and wires to the circuit.
Are common specifications such a device will be as follows: the resistance of the resistor from 0.23 Ohm(may be a little more or less), an indicator of the operating current value (taking into account cooling by a fan) - 15 amp, voltage standard - 12 volt. As for resistors of this particular type, their advantage is that they have built-in fuses that operate in case of overheating inside the circuit. If one resistor is used, the load indicator with it will be 50 amperes, and if two are in parallel, then, respectively, 100 amperes.
Non-standard solution to the problem
In this case, the load fork is made even more interesting way, using a sewer pipe, carefully cut in the longitudinal direction.
Here is a diagram of the design of the plug, designed to check the resistance indicators of 12 volt batteries with a capacity of several tens of ampere-hours:
- constant wire , 12 turns with an internal winding diameter of 38 mm;
- welded to the ends of the wire studs M8;
- all of which could be perfect for sewer pipe if it diameter is 50 mm;
- gap closes the second piece of the same pipe;
- On the sides established plugs, and the design is ready.
Technical parameters: resistance index approx. 0.1 ohm, current at voltage 12 volt is 110 to 120 amps. The duration of the load in this case should be minimal, no more than 3-5 seconds (unfortunately, the device heats up very quickly). All battery indicators are measured in the same way, with a voltmeter of any type. When creating such a plug, it is recommended to use the table for calculating the resistance of wires of various lengths.
General recommendations for the design of homemade load forks
Before you start assembling the plug yourself, do not forget to measure the voltage readings in each battery bank and check the ability to access the banks. It also does not hurt to re-read the instructions that came with your battery: it contains the minimum and maximum current values \u200b\u200bfor it under load, which is very important.
The clamps used for measurements must be strong so that they can withstand a large current when a load is applied to the battery. It is better to attach the "crocodiles" to the battery using strong wires.
All connecting parts of the electrical circuit must be firmly soldered. To do this, you need a good welding machine.
And a few more important tips:
- correctly calculate the power to avoid overheating;
- don't join homemade device to the battery while it is charging;
- do not store a homemade plug near batteries;
- ventilate the room before and after working with your device;
- do not hold the plug longer than 3-5 seconds to avoid damage to the battery.
As you can see, a do-it-yourself battery load plug is easy to make. It is important to remember from a school physics course how to correctly calculate resistance indicators, and correctly assemble an electrical circuit from suitable improvised means. Also, when using a homemade load plug, do not overdo it with current and carefully monitor its performance.
The load plug is used to visualize the state of charge of the battery and is an excellent measuring device for calculating possible problems when testing. In addition, the built-in load plug voltmeter is well suited for surface diagnostics. onboard network car. In simple words we can say that the load plug is an ordinary voltmeter, in parallel to which the load is connected, in the form of a spiral.
There are many types of load forks. But they differ only in the voltage measurement range and load rating. You can also conditionally divide all the load plugs according to the type of tested batteries. That is, there are plugs for both acid batteries and alkaline batteries.
Examples
: voltmeter with a maximum voltage measurement range of 3-0-3 volts. Current load - 100 amperes. Used to test 1.2 volt alkaline batteries and to test 2 volt acid batteries.
Voltmeter up to 20 volts, load resistance 0.1 Ohm, load up to 100 amperes is possible.
It includes an electronic voltmeter with a liquid crystal display. It has two loads of 100 amps, with the possibility of separate connection. When connecting one load, batteries with a capacity of 15 to 100 Ah are checked. When two loads are connected, batteries with a capacity of 100 to 240 Ah are tested.
Plug HB-03 also includes some additional features: automatic detection the degree of charge of the battery; recording measured values in the memory, etc. In addition, NV-03 has the ability to calibrate the voltmeter and the range of temporary voltage measurements. Therefore, before carrying out measuring manipulations, it is necessary to make sure that the fork is calibrated.
Load plugs are available for different voltage measurement ranges. But remember that the measured voltage should not be higher than the maximum value of the load plug voltmeter. For example:
2-0-2
volt (for alkaline batteries with a voltage of 1.2 V)
3-0-3
volts (for 1.2 V alkaline batteries and 2 V acid batteries)
0-15
0-20
volt (for acid and alkaline batteries with a voltage of 12 V)
0-30
volt (for acid and alkaline batteries with a voltage of 24 V)
Choice of current load |
During the load test of the battery, we connect the load of the plug to the battery, creating a discharge current in the resulting circuit.
For more better check Battery, this current should have a maximum rating, but it should not exceed the allowable discharge current of this battery. I advise you to focus on the following data:
for traction alkaline batteries - the current of the 3-hour discharge mode (0.33C, where C is the nominal capacity of the battery in A * h);
for traction acid batteries - the current of the 1-hour discharge mode (1.0С);
for starter batteries of both types, acidic and alkaline from 1.0C to 1.4C
The current of the n-hour discharge mode is the current, during the discharge of which Rated voltage battery is reduced to an acceptable minimum level for a given period of time.
Checking battery voltage without load. We disconnect the load from the voltmeter of the load plug and measure the voltage on the battery.
Checking battery voltage under load. We connect the load and divide the next measurement of the battery voltage. The load fork voltmeter reading is most accurate after the fifth second of measurement. The degree of battery charge is determined in accordance with the table:
The measurement process should not be carried out for more than ten seconds, since the spiral loads are very hot and the measuring device may fail. If the battery is not 100% charged, then it must be fully charged. After that, test the battery again with a load plug.
If the percentage of battery charge, without load, is higher than under load, then they say that the battery “does not hold the load.” Therefore, urgent measures are required to restore capacity. And for this, it is desirable to deal with the factors of capacity drop and the need for further operations to restore the battery.
This home-made design for testing car batteries has good accuracy due to the use of an extended scale. The built-in load resistance makes it possible to measure the voltage both under load and in load plug mode. The device has a narrowed range of 0 - 10 V per quarter of the scale, and the rest of the range is 10-15 volts, which significantly reduces the measurement error. A car battery is considered fully charged at 14 V and fully discharged at 11 V. To be able to measure the values of individual cans of the battery, a three-volt scale and a different output of the measuring device are used. An extended scale of 15 volts is obtained due to the voltage drop across the zener diode and diode. If the voltage level is higher than the opening level of the zener diode, the current through the device increases. The diode also performs a protective function in the event of a voltage supply of the wrong polarity.
When selling an acid car battery, an honest seller tests it with a load plug. He shows that he sells a battery ready for use, and not a half-discharged battery with the first signs of sulfation stale in a warehouse.
Device
The load plug is a simple device that combines a multimeter, a resistance spiral, an alligator clip with a wire, a case, and a load switch. They differ from each other according to the following criteria:
- by type of voltmeter (digital or analog);
- voltmeter accuracy;
- spiral resistance (0.1 ohm is equal to a load of 100 amperes);
- measured voltage;
- type of connection to the battery.
A digital voltmeter is good because it is easier for them to visually show that the voltage is growing under load, because. it grows, as a rule, imperceptibly to the human eye in comparison with an analog voltage meter.
Some experts are inclined to believe that it is not desirable to test batteries with a capacity of 55-75 A with a load of 200 A, but these are unfounded fears. In cold weather, when starting the engine, the load on the battery is much more significant.
How to use: instruction manual
To check the battery, you need to make sure that the battery terminals do not have any signs of corrosion and oxidation. If under load the contact with the terminals is poor, the multimeter will give incorrect (underestimated) data.
Next, we hook the crocodile to one of the battery terminals (usually negative). At this point, nothing will happen to the multimeter. Then you need to make sure that the load at the plug is turned off. If you first measure the battery under load, and then without load, the voltage will show less than vice versa. We recommend evaluating the battery charge level as follows:
- 12.70 V or more - excellent charge;
- 12.60 V -12.69 V - good charge;
- 12.50 V -12.59 V is a satisfactory charge.
Lower than 12.50 volts - the battery needs to be charged (at charger), its operation is undesirable, especially in cold weather, because electrolyte may freeze.
More detailed data are shown in the figure.
Thus, we will check the degree of charge of the battery. But this is not enough. Even an old battery can show a voltage of 12.77 V (especially if it has just been removed from charging), but it will not be able to start the car engine. The reason is that the starter has a strong resistance, upon encountering which the battery voltage will begin to drop sharply.
The next step will be a load test. The process is similar to the previous step, but only with the spiral resistance mode turned on. The battery in this mode produces 20-30% less voltage than in the simple mode of the multimeter. Here the main point will be that the voltage of a good battery will begin to rise during the measurement.
If you test the Arctic Batbear battery (photo), then at first it will give out 10.5 V and in 5 seconds it will rise to 10.9 V (!!!). At the same time, many cheap batteries increase the voltage by only 0.1-0.2 V.
Delusion. Some motorists, and even those who sell spare parts, believe that a load fork can determine which battery is better. Sometimes they ask to get 3-4 identical batteries and choose the one that will show under load best performance. It's a finger in the sky, especially in the latest trend of "lightweight batteries", because. An honest 12.6V battery will last longer and start better than a lightweight 12.7V battery.
Overview and rating of load forks from different manufacturers
There are only a few manufacturers of load forks on the shelves of Russian car dealerships, we will study them and make our own rating. The rating methodology is to study the characteristics of devices and identify the pros and cons. So, let's begin.
Autoelectric T-2001
The first tester we'll cover in this review. It is well known to sellers of specialized stores. This tester used to be an ideal option, if not for one “but” - to switch to the load mode, it was necessary to sink the sting, which closed the contact to the spiral, it burned and the plug quickly failed.
Auto electrician T-2001 mini
This tester has replaced its older brother T-2001. The modern T-2001 mini took into account the disadvantages of the former and began to cost less due to the transition to a resistance of 100 A. This device is primitive, but at the same time reliable.
He revealed only one minor minus - during assembly, it is necessary to clean the seat of the handle from paint, because. it is not conductive, so it may not work properly.
Master 122-0001
It looks like a serious tester for current sources. It has a multi-colored scale with several measurements, which visually gives it seriousness. Also of the pluses - "ears-brackets" for crocodiles, which allow you to avoid tangling wires. Everything is in its place. It is not a shame to measure Optima and test Warta with such a measure. Produced in Taiwan.
Orion NV-01
The most primitive resistance voltmeter in our test. Small curved metal box with a handle. Particularly frivolous gives the appearance, at first glance, which is perceived as something assembled from a tin can in the garage. Such a unit cannot inspire confidence, especially since a small scale creates a large measurement error. 
Orion NV-02
Improved model of the previous sample. It has a powerful crocodile, a large wire, a thick sting and a factory case. At the same time, the characteristics are similar to the previous model and it is possible that the filling has remained the same (write in the comments if you disassembled and compared).
Orion NV-03
Modified previous model. Here, a digital voltmeter monitor and two connected spirals of 100 A each are already used, which makes it possible to attribute this device to the professional category. This device has one plus, which is insignificant in practice - it is able to store measurements in its memory. It seems like a trifle, but nice.
Orion NV-04
Slightly modified for truck services model HB-03. It has a large range for a voltmeter. The rest is no different from the previous fork. If you do not have a truck service, take the previous version of the tester, you will not overpay.
Ermak (2 wires)
Even the manufacturer does not write about this device. Although, apparently, Ermak is not a manufacturer, but rather a logo and colors. Other instruments are also made under these brands. Accordingly, this device is most likely an import manufacturer of the Aliexpress level. Therefore, choosing before buying, twist it in your hands, ask to see it in action. So far, the only plus of this toy is the appearance at a low price.
Ermak (1 wire)
Similarly, like the previous model of this brand, it is a copy of the original tester Orion HB-01. The last place in our ranking.
Plug scheme and principle of operation
All load forks have a simple principle and an elementary circuit. Among the considered devices, 3 different electrical circuits were identified:
Ermak is tested with one coil, with two - ORION NV-03, NV-04, with a resistor - Aist.
How to make a load fork with your own hands
We do not recommend assembling the load fork with your own hands. First, it is dangerous from a security point of view. Secondly, if you need a plug for work and often, you can buy a cheap and simple type Orion-2 or Autoelectric H-2001 mini. Thirdly, if you want to test your battery to find out its condition, then it is better to take it to a specialized center, they usually do battery diagnostics for free.
Many motorists have found themselves in a situation where there is at hand, and the degree of its readiness for work is unknown. And I want to quickly determine whether it can be put on a car. The simplest device for testing a battery is a load plug. Having it at hand and having a little knowledge of its application, you can almost instantly determine the health of the battery, and at the same time assess its level of charge.
Load fork device
There is nothing complicated in the device of the battery plug.
Modern looking battery plug
Regardless of the type and design, it includes the following elements:
- Voltmeter with a measurement range corresponding to the voltage of the battery under test.
- A low ohm resistor that, when connected, provides operating current to the device powered by the battery under test. It can also be a homemade nichrome wire resistor.
- Wires and clamps for connecting the load to the battery terminals.
- Most modern devices a switch or button is installed to connect the load to work.
It is not entirely clear why this measuring device is given the name fork. Perhaps this name came from the fact that the first models had protruding contacts in the form of "horns" instead of clips and wires. And the whole structure appearance really looked like a plug that was "plugged" into the battery being tested.
One of the old types of load fork
The principle of operation of the measuring device
Since a voltmeter is necessarily installed in this device, any battery load plug can also be used to check the voltage at any point on the vehicle's on-board network. But its main purpose is to test the battery, that is, to check its readiness to provide the operating current value.
The plug terminals are connected to the battery terminals, and then the load is “turned on” for a short time. By the level of voltage that the battery produces after connecting the working resistance, and by its change, a conclusion is made about the degree of readiness of the battery and its serviceability.
Basically, such devices are used for car batteries rated at 12 V or 24 V. Therefore, the voltmeter measurement scale should be up to 15 V, less often up to 30 V. The operating current that ensures the start of a car starter is 80 - 120 amperes. The connected resistance of the device must provide such a current at the corresponding battery voltage.
Before turning on the load, it is useful to check the amount of battery charge. To do this, you need to measure the potential difference at the battery terminals in no-load mode.
For 12-volt batteries, their charge is estimated according to the following voltmeter data:
Battery charge assessment, checked in idle mode
It is clear that it makes no sense to check the operation of a weakly charged battery under load. By loading such a battery with a large current, it can simply be damaged. First, it must be recharged, and only then arrange a readiness check.
A fully charged battery is to be tested for readiness for operation. To do this, the working resistance of the plug is connected for a few seconds. According to the readings of the voltmeter, the degree of readiness of the battery is determined.
Connecting a battery plug with a load to the battery
The assessment of the readiness of the battery for operation is carried out in accordance with the data given in the table:
Battery readiness assessment, tested under workload
It is worth noting that an additional indicator of battery life is a change in voltage at its terminals. For serviceable batteries, immediately after connecting the load, the voltage “sags” to the minimum reading, and then gradually increases by 0.2 - 0.5 V in a few seconds.
Varieties of load battery plugs
Even such a simple device is available in various versions. And this applies not only to his appearance.
Plug with dial indicator and two wires
Load battery plugs differ in the following characteristics:
- Type of voltmeter. Now more often they use digital scoreboards instead of turnouts. They give a better perception and allow you to more accurately assess the change in voltage when testing under load.
- The range of the measured voltage and the accuracy of the measurement scale.
- The value of the resistance of the connected load.
- Changeable load resistance. At different types batteries, the operating current can vary greatly. If the device contains several interchangeable load resistors, then they can test the battery at different load currents. In modern load forks, the change in load resistance is carried out not by mechanical replacement, but by changing the load mode on the electronic display.
- Option to connect the device to the battery terminals. There are two-wire and one-wire load plugs. In the second case, the role of the wire is performed by a contact pin located on the device body.
Plug with digital display and one wire
How to properly use a battery charger
A simple device corresponds to simple instructions for use. But following simple rules will ensure the reliability of data on the state of the battery. And their violation can damage both the test device itself and the tested battery.
- Measurements with a connected load should be carried out for no more than 10 seconds. This time is enough to get all the necessary data. And prolonged operation under load will lead to excessive discharge of the battery and to overheating of the device's own resistance.
- A suitable temperature for testing is 15 - 20 °C. Standard calibrations are carried out at this temperature. Yes, and once again load the battery, forcing it to work in sub-zero conditions, should not be.
- It is necessary to check the reliability of the contacts when connecting the plug wires to the battery terminals. Bad contact will result in unreliable test readings.
- Do not use loads that provide a test current of more than 120 amperes. Yes, there are currents up to 200 A at startup. But a battery that can reliably deliver 120 A can withstand 200 A if necessary. Once again, it is undesirable to test under the most extreme conditions.
How to make your own battery charger
If desired, you can make a homemade load fork. Of the finished products, you only need a voltmeter. Everything else can be built from improvised materials.
The greatest difficulty is the calculation and creation of internal resistance, designed for the required current. If you do it yourself, then the most suitable material would be nichrome wire from the heating coils of electric stoves. You can pick up a metal strip from other heaters. In order to provide a current of 80 - 120 A at a voltage of 12 V, the load resistance should be 0.1 - 0.15 Ohm. Finding a multimeter that can accurately measure such resistances is difficult. Therefore, it is easier to choose the length of one element by measuring the current passed by it, and then connect several such wires or strips in parallel.
Fork operating resistance calculation
Procedure:
- Using a multimeter with a measured current range of up to 15 A, the length of one nichrome wire or heating strip is selected, providing a current of 10 - 12 A. Or, with an accurate multimeter, measure the resistance of 1 - 1.2 Ohm.
- Parallel connection of 10 such elements will allow you to get a load that passes a current of 100 - 120 A.
- All elements are connected in parallel. It is better to twist the wire into a "braid". For more reliable twisting, they can be clamped in the chuck of a drill or screwdriver.
- The manufactured resistance is placed in a suitable case and fixed in it. If you have to bend it several times, then you need to ensure that the turns do not touch each other. For reliability, insulating cylinders can be put on the bending points.
- The ends of the resistance are soldered to the output contacts, and the connecting wires are soldered outside.
Homemade load resistance for the battery plug in the housing
- A voltmeter is connected in parallel to the load.
- Clamps are attached to the ends of the connecting wires for connection to the battery terminals.
The load plug is an important device for an auto electrician and is necessary for competent testing of a car battery. Drivers who prefer to service their car themselves often want to learn how to make this device on their own at home.
Making a load fork yourself is not a difficult task if you have the necessary knowledge, tools and parts. In order to correctly assemble the tester, you need to find out what it is and how it works. Read on for the secrets of making a fork.
A load fork is a device that analyzes the operation of a car battery, sometimes it is called a unloading fork, but there is no difference between them. A classic device consists of a voltmeter and one or two resistance spirals (resistors), to which two probes are connected.
In some cases, the load plug also includes an ammeter. The view of this unit is a small metal box, to which wires and clamps are attached: 
Older load forks are usually equipped with analog voltmeters. The new models are already equipped with predominantly digital voltmeters and LCD displays. There are also load plugs that have a complicated circuit that use several interchangeable resistances (spirals).
These devices, designed to measure different voltage ranges, are used to diagnose both acid and alkaline batteries. There are special load plugs for testing individual cans of batteries.
This device can be used not only to check the performance of the battery, but also to obtain data on the operation of any part included in the electrical circuit. The main function of the load fork is voltage control. Voltage measurements can be taken using the electromotive force under load, as well as when the EMF circuit is open.
With this device, you can determine various parameters of electrical appliances. It all depends on the configuration of a particular device.
Purpose of the device
- Determine the time that the battery stores electricity. It depends on the capacity of the battery. If the battery has a capacity of 50 A / h, then it will be able to hold a charge for approximately 141 days if the device is not supercooled and kept at a positive temperature.
At the same time, if the battery is in the car and connected to the network, then the charge retention time is halved. The thing is that electricity is consumed even when idle. If there is an alarm in the car, current leakage (in the region of 0.02 - 0.05 A / h) also occurs when the battery is at rest.
In winter, with such a loss of energy, the battery will be discharged in 10 days, but if the temperature is positive, the discharge time will be about 20 days.
- Measure the degree of charge. If the voltage on the battery is 11.7 Volts, the battery is discharged; from 12.1 to 12.3 Volts - the battery is half charged; 12.7 Volts - fully charged.
- Find out how long the battery can still hold a charge. It is important to know when to charge the battery. By default, the battery needs to be charged when the battery voltage drops below 12 volts. Already at a charge of 11.9 volts, the battery capacity remains only 40% full. In this case, it is better to charge the battery in a warm room, without waiting for frost.
- Check if there is a short circuit between the plates. A short circuit exists if during the plug test: the voltage drops below 9 volts; the electrolyte boils in a closed jar; when a voltage of 14.4 volts is applied, the electrolyte boils in a closed bank or in all banks except for a closed one.
- Set the generator voltage value at the output. The output voltage level must be stable. The car battery is sensitive to such changes. If the voltage level is below normal, the battery will not charge to the required extent.
Due to such problems, problems usually arise with starting the car engine. Otherwise, when the load plug detects an increased voltage, the battery will be recharged and the battery will wear out quickly.
Using clamps, the device is connected to the terminals of the car battery or to other parts of the electrical circuit. If the device is equipped with an ammeter, it can be used to measure the current.
An important indicator is the number of spirals in the load fork. The resistance level of each of them is 0.1-0.2 Ohm, they are designed for 100 A. If there is one coil in the device, you can check the charge of batteries with a low capacity (6-12V) with a load plug, if there are two coils - a larger (24V).
Different models differ from each other in such parameters as:
- the clarity of the data obtained (the measurement error usually lies in the range from 2.7 to 2.9 seconds);
- type of voltmeter (digital, analog);
- coil resistance (0.1 ohm corresponds to a load of 100 amperes);
- temperature at which the load fork can be used ( universal devices usually operate at temperatures from +1°С to +35°С, powerful plugs can operate in the range from -30°С to +60°С);
- the range in which the voltmeter operates (when measuring voltage is 0–15 Volts);
- test current;
- area of operation (acid or alkaline batteries).
A digital voltmeter is good because it is easier for them to visually show that the voltage is growing under load, because as it grows, as a rule, it is imperceptible to the human eye in comparison with an analog voltage meter.
Making a load fork with your own hands
The self-made load plug is suitable for use with 12-watt batteries. The assembly scheme of the device may differ in nuances. The essence of the device is a load-rheostat connected through a switch.
Simple to manufacture and inexpensive to purchase, the device will be useful in the garage of a motorist. Using a load plug will show how "tired" your battery is and how your car's alternator is performing. If you don’t want to buy (which is not surprising, given how much it costs), you can make this tester yourself.
Important! Proceed to self-manufacturing A load plug is only worth it if you have at least minimal experience with electrical equipment.
Materials for manufacturing
Scheme
Single coil load fork
R - resistance, V - voltmeter, S - switch.
Load fork with two coils
For testing batteries from 15 to 100 Ah. one load (100 amperes) is connected to check the battery with a capacity of 100 to 240 Ah. two loads (200 amperes) are connected.
Step by step instructions: how to do it yourself
Described above the simplest circuit making a homemade load fork. A device made in this way can become the basis of a design, to which, for example, an ammeter, a clock, etc. can be added.
Important! All elements must be well connected! This will help the welding machine.
Useful video
When making a homemade load fork, you can use this helpful video.
- The battery cannot be used if the battery terminals are coated with oxide. They need to be cleaned before use.
- You can measure the voltage only after disconnecting the battery from the car and only after 6 or more hours after turning off the engine. The battery must also spend all these 6 hours in the off state before connecting to the plug.
- Probes are connected to each jar separately!
- If you connect the load plug to the power source for more than 6-10 seconds, the assembled device will quickly fail.
- The electrolyte level for diagnosis should be at a normal level. When lowered, distilled water is added.
- Forbidden store the instrument near batteries and similar devices.
- After use, it is necessary to ventilate the room well.
Conclusion
Using a battery with a low charge in a car threatens with serious consequences and a long recovery time. For normal operation of the vehicle, the driver must regularly check the battery. The load fork is a device that helps diagnose the performance of this important part of the machine.
