Many motorists consider it normal to regularly, every 1 - 2 years, purchase new batteries for their cars. Complaining about the low quality of products produced under little-known and well-known brands, they go to stores to leave their honestly earned money, which, as we know, is never superfluous.
Meanwhile, there is a high probability that the problem is not at all with the power source. To make sure of this, you should perform a few simple checks, starting with the generator.
Car generator power. How to recognize (define) it and what it depends on
A lot of motorists are interested in the power of a car generator. After all, there are now a lot of electrical devices (for example, inverters) that can turn your car into practically a power plant for a country house. Many carry loads of 1000 – 1500 and even 2000 W! Is it a lot or a little? Can a running car do this? Some write that – NO! Others that - YES! But often they have a “mess” in their heads; I often see such statements on forums: the power is no more than 300 - 600 W. Where these numbers come from can be seen from the ceiling. Let's correctly define power, and also find out what it depends on...
In this article I will introduce you to the approximate power of your car alternator, this is physics grade 7. Let's take into account that we have direct, not alternating current.
What to look for when choosing?
There are a number of details that you need to pay attention to before purchasing a generator. First of all, look at the packaging:
1) the addresses of the supplier and manufacturer are required on the box - unless, of course, they have nothing to hide; 2) information about product certification (STP, EAC, ISO) - the product must comply with technical standards. If there is no certificate, you should not buy a generator; 3) information about the guarantee: from what moment it is considered and for what period it lasts. For example, the warranty on generators is valid for 2 years from the date of sale, but there are cases when the period is counted from the date of production; 4) information about the original codes of the product and its applicability to your car model - it will be unpleasant if after purchase you find out that it does not suit you; 5) their own system for identifying spare parts - bona fide manufacturers have their own unique part numbers for specific car models: for example, the StartVOLT generator for a VAZ 2110 car has the manufacturer’s brand designation LG 0110; 6) the presence of a seal or liners in the box to protect against mechanical damage.
Please check the completeness of the product before purchasing it. The box should contain:
warranty card - without it you will not be able to return a defective product to the store or directly to the manufacturer; additional documents, including a product passport, instructions, test results or promotional materials. The more documents, the more information you can get about the product; Some generator models are additionally equipped with separate fastening elements (for example, a generator mounting bracket). If they are not there, installing a generator will be extremely problematic.
Packaging of the StartVOLT generator with documents
Remove the generator from the box and perform a visual inspection:
Any chips, scratches or other defects are unacceptable - damaged goods cannot be purchased. The consequences of using such a spare part will be its complete destruction during operation; it is necessary to inspect and check the tightness of the main fasteners of the generator, at least by touch. Please note that before installing the product, you do not need to check the tightness of the second (outer) nut of the generator output bolt, if there is one (terminal B+) - they are not specially tightened to make connecting the product easier; turn the pulley and listen for any extraneous noise when it rotates. The noise indicates poor quality assembly; such a product should not be purchased, much less used; Some stores have special testing equipment. so as not to “bite your elbows” later, it is better to spend a little time and carry out a test at a specialized stand.
Other causes of low voltage
A small potential difference in the system is not always associated with a breakdown of the generator or a bad battery. If the diagnosis of these elements does not reveal any problems, then you should pay attention to the following:
- condition of the battery terminals - connection density and oxidation;
- electrical wiring problems - oxidation, violation of its integrity;
- output contacts to electrical appliances;
- correctly selected energy consumers.
Each contact must be tightly adjacent and intact, that is, there must be no formations (for example, sulfation) that will disrupt the flow of current. Incorrect connection of contacts leads to accelerated battery discharge even when the car is not running.
To improve the connection of the elements of the car's electrical system, it is necessary to clean all contacts and restore the integrity of the wires by replacing them or connecting them and wrapping them with insulating tape.
Device
Externally, all generators are similar at first glance, but those who are familiar with electrical engineering can easily determine which device they are dealing with. The situation is simplified by the fact that DC machines were used only on very relic cars, long out of production.
DC generator
The DC dynamo includes:
- frame;
- field windings on a stator fixedly fixed in the housing;
- power windings on a rotating armature;
- brush assembly with copper-graphite or carbon brushes that remove current from the rotating armature commutator;
- a voltage regulator that stabilizes the output by regulating the excitation current in the stator electromagnet windings;
- drive pulley on the armature shaft;
- bearings in which the armature shaft rotates.
What is a generator in a car and what is it for? Generator in the car
What questions do the car owner have during its operation regarding the operation of the generator? The most varied. Let's try to summarize them, essentially. 1. What is the best way to select a generator based on power (current) for specific on-board equipment (powerful audio installation, computer system, lighting equipment)?2. What is the relationship between the battery capacity and the required current output of the generator?
3. How to check the constituent elements of the generator and determine the faulty element?
4. How to analyze the energy balance of a car?
And so in order:
Standard generators installed on serial products provide normal power supply to the on-board network with a small margin. Wanting to make it easier to start the engine in winter, many try to install a battery of maximum capacity that can be installed in the place provided on the car. Usually, instead of a 55 Ah battery, it is possible to install a 72 or 75 Ah battery. And for new batteries up to 80 Ah. What do we get? It all depends on the condition of the electrical wiring: if it is in good condition, losses at the contacts are minimal, the generator produces the current it is supposed to, and without voltage drop under load, then everything will be fine. But if the machine is aged, there are loose connectors, oxidized mass contacts, then instead of improvement you can only get worse. For example: in winter, at night, in snowfall - let's see what happens:
— dimensions and lighting of license plates, instruments and interior 6x5W+5x2W= 40W — headlights+foglights rear and front 2x65W+2x45W+2x21W= 250W — heater fan at maximum current mode up to 18 amperes or 200W. — radiator fan for a short time (2-3 minutes) approximately 250 watts. — heated rear window about 150 watts. — fuel pump and engine control system about 70-100 watts. — radio in medium volume mode 100 watts.
It turns out a total of 1100-1200 watts, which is about 70-100 amperes, i.e. the generator will work to the limit, especially when the radiator fan turns on. What about a 400-1000 watt amplifier and 100 watt halogens? Now it’s time to think about a second generator. Of course, I exaggerated, and you can limit your consumption a little, don’t turn on the rear fog lights, turn on the heater at 2 or 3, and the radiator fan works for a short time (during this time you can turn off the rear window heating). In this case, it would be useful to have a digital voltmeter on the instrument panel connected directly to the battery terminals. If the voltage on it begins to decrease, then it makes sense to turn off something. Don’t forget, after all, the battery also consumes some current, and the more the battery gives during start-up and during parking, the more it will take on after starting the engine, and the greater its capacity, the greater the appetite. Therefore, it makes sense for music lovers to replace the standard generator (hereinafter I am thinking, keeping in mind, by default, VAZs of all types and models), with a nameplate current of 80 amperes, with a more powerful one of at least 100-120, and preferably 150 amperes. But do not forget that 120 amperes of output is already almost 2 horsepower minus the engine thrust. You have to pay for everything! It also makes sense for owners of foreign cars to estimate these calculations; ideally, take DC current measuring clamps and see what flows from the generator to the battery, and how much flows out through the second wire from the battery. Usually no one makes such measurements. And it’s very useful to broaden your horizons and understand the real picture of the energy balance! But technically competent owners who are able to understand the picture and, after analyzing, draw the right conclusions, are the only ones.(!) Of course, after reading all of the above, and taking into account your experience and feelings, you can draw more meaningful conclusions. Is it worth it to install cheap 100/110 watt halogens in the headlights, and heat the headlight optics and relay contacts in MB, instead of buying expensive branded lamps with good light output and a power of 65/50 watts, and have even better illumination of the road with less power. Or install more economical but expensive xenon lamps? In conclusion on the first question, a note on amplifiers and powerful music. When installing a high-power audio system, remember that it will draw an average current of 20-40 amps (and up to 50-80 amps at peak power) at 400 watts of power. The calculation is simple:
14 volts X 50 amps = 700 watts with efficiency = 65% (for an amplifier this is close to ideal)
we will have a useful power of about 400 watts. Of course, listening to music at such a volume level is dangerous for your hearing, but there is no point in explaining this. Everyone must step on their own personal rake! This is assessed later, when at the medical examination they are unable to hear at least some of what the “ear” whispers while testing their hearing.
Signs of a generator malfunction
In modern cars, breakdowns of the electrical system are one of the most common. A large number of electronics requires particularly careful monitoring of the operation and condition of the generator and battery, because their failure can immobilize the car. The most common signs of a generator malfunction are:
- battery indicator light on the instrument panel;
- unstable operation of the battery (its boiling over or undercharging);
- different intensity of headlights;
- extraneous sounds from the generator.
If you notice incorrect operation of the car, then perhaps the battery charging current from the generator is insufficient.
All malfunctions of electrical equipment, which includes the vehicle’s energy-generating device, are mechanical (deformation or breakage of fasteners, housing, malfunction of bearings, pressure springs, drive belt, etc.) or electrical (winding breaks, diode bridge malfunctions, burnout or wear of brushes , short circuits between turns, breakdowns, etc.).
Don’t write off a non-working generator: find out if there are repair kits and spare parts. Replace them if possible. If you cannot carry out repair work yourself, then take the generator to a workshop. Many craftsmen will be able to restore the unit at no extra cost and in the shortest possible time.
However, some breakdowns require the purchase of a new device that generates electricity. For example, a failing bearing that is soldered into the generator housing cannot be restored or replaced in most cases.
Remember that failure of this unit can be caused not only by wear and corrosion, but also by poor quality of elements and components; excessive load; external influence of salts, liquids, temperatures.
Minimum battery input voltage parameter
When checking the parameters of the generator, it is worth taking into account the characteristics of the battery itself.
Many car owners are interested in what the voltage at the battery output should be for normal engine starting.
There is no exact answer here, but the average parameter should be 12.6-12.7 V. Depending on operating conditions, this indicator can be adjusted.
Some manufacturers claim that their product has a voltage of 13-13.2 Volts. This parameter is real, but you should not measure the voltage immediately after recharging with a generator or charger.
It is advisable to wait 1-2 hours before carrying out work. In this case, U should drop to a level of 12.7-13 V.
If this parameter begins to “float” or drops below 12 V, this indicates a 50% battery discharge or a generator malfunction.
It is recommended to check the charging circuit or use an external charger.
If you continue to operate the battery in this condition, sulfation of the lead plates occurs, which reduces the performance of the battery and reduces its service life.
In practice, such a decrease in voltage is not critical, because the battery can still be started, and then the generator recharges to the required level.
The main thing is to make sure that the charging circuit is working properly and that the voltage at the battery terminals is increasing.
If U at the output drops below 11.6 V, we can talk about the complete discharge of the power source.
In this case, further use of the battery is impossible - it must be removed, checked for serviceability, and charged from an external device.
Taking into account the above, we can conclude that the voltage on the battery with a working generator should be (with the engine off) 12.6-13.2 V. In practice, this parameter is slightly lower and amounts to 12.3-12.5 V.
This voltage indicates a slight undercharging of the battery. There's nothing wrong with that. The main thing is not to allow U to decrease below 12 V.
How many amperes does a car alternator produce per battery?
The current strength required by the electrical system of each car is individual and depends on the number of electricity consumers and their values. And also the charge current must be sufficient to charge the power source.
It is worth noting that ampere readings appear only when there is a load in the vehicle’s electrical system and, accordingly, the battery is discharged. After starting the car engine, the charging current is about 6-10 amperes and drops over time, because the battery is charging, taking on the main energy consumption. If you turn on additional equipment - headlights, radio or heated mirrors, you can see an increase in the charging current values.
When purchasing a generator, pay attention to its technical characteristics, which the manufacturer indicates on the case - that’s where you will find information about the maximum current that will flow to the battery.
In the table below you can see the approximate current values that the generator shows at different loads.
Table 1. How many amperes the generator produces under load.
Characteristic symptoms of a malfunction
The on-board network of a car is a single organism in which everything is interconnected. Incorrect operation of the generator is the most common cause of battery failure. Several options are possible:
- Low charging current. By itself, it is not capable of causing serious damage to the battery. However, a power supply that does not fully recover its potential quickly loses capacity. It becomes difficult to start the engine.
- High charging current. Due to this malfunction, the electrolyte boils away and, as a result, sulfation of the active substance on the plates occurs, and the battery fails.
- Voltage surges. As a result, light bulbs often begin to burn out, and the life of other electrical equipment is reduced.
In any case, troubleshooting measures should be taken without delay.
Generator voltage under load
To ensure the functionality of the power supply, it is recommended to perform a load test.
To begin with, remember that there are three types of voltage:
- Nominal - indicated in the operating instructions. It is 12 Volts. This figure is far from the actual U value.
- Actual . Here we are talking about the voltage parameter after installing, connecting and starting to use the car battery. On average, this parameter is 12.6-13.2 V (this was mentioned above).
- Under load . Here the voltage parameter supplied by the generator can change.
The presence of a load allows you to verify the health of the battery and generator.
A seemingly serviceable battery with an output of 12 V can drop significantly after switching on the consumers. During the testing process, an additional device is used - a load fork, which allows for an increased load on the battery.
Let's give an example.
If your battery capacity is 60 mAh, the load value should be 120 A. The connection duration is 3-5 seconds.
We can say that the power supply is working properly if the voltage does not drop below 9 Volts. If the parameter drops to 5-6 V, this indicates a complete discharge of the battery. After testing under load, the voltage should return to 12.2-12.4 V.
If a strong drawdown is detected, it is necessary to check the battery, and then repeat the experiment with the plug again. If there is no drawdown, we can talk about the health of the battery.
To check the generator, you can do the following: start the car, turn on as many consumers as possible, and then take a measurement. The voltage should be 13.5-14 V.
If it is lower, this indicates a failure of the generator. The lower critical limit is 13.0 V.
If the voltage of the car's generator is very low, do not rush to draw conclusions - make sure that the contacts on the battery are not oxidized. If so, rub them with sandpaper.
The generator does not charge: reasons
Let us note once again that a normally operating generator completely replenishes the battery charge level, while the charge decreases under load. At the same time, in the general circuit there are many elements that can cause a battery charge failure. Often, problems arise both in the mechanical part (generator drive, bearings, etc.) and in the electrical part (break or short circuit of windings, burnout of the diode bridge, wear of brushes, breakdowns). The generator relay regulator should also be checked separately.
One way or another, it is important to find the problematic element. Note that usually the vast majority of generator breakdowns or battery charging problems can be eliminated (by replacing the drive belt, rollers, repairing the generator, inspecting contacts, terminals and other elements). However, there are breakdowns that become the basis for replacing the entire generator assembly.
We also recommend reading the article on how to increase the density of the electrolyte in the battery. From this article you will learn what the density of the electrolyte affects, how to measure the density of the battery, and also how to change the density of the electrolyte in the battery.
A situation also often occurs when the generator is working, the battery is normal, but there is still low voltage. Moreover, diagnostics using the methods discussed above may not reveal problems. In this case, special attention should be paid to the battery terminals.
The terminals must fit tightly; oxidation is not allowed. The same goes for electrical wiring. All wires must be intact, and the contacts must be securely fastened and clean. By the way, it is important to periodically clean the contacts from oxidation, since the current will pass through the oxidized outputs worse.
You should not yet rule out mistakes that may be made during generator maintenance. Incorrect contact connections can cause generator malfunctions, battery discharge and other malfunctions.
