A car subwoofer capacitor is becoming increasingly popular among car owners. Now the installation can be found not only in expensive audio systems, but also in simple sets of audio equipment that use external sound amplifiers.
Do you need a capacitor for a subwoofer? Drivers who understand the meaning and functionality of the device answer unequivocally: of course it is needed. Since this device significantly improves the performance of the amplifier, as well as the quality of the sounds produced.
Operating principle of a capacitor
For modern subwoofers, short-term peaks are enough to start drawing more current. As a result, it cannot fully provide energy to the battery. Even the thick wires that feed the amplifier do not have such resistance that will cause a decrease in voltage at the moments of the pulses.
Connecting a subwoofer to an amplifier and capacitor
As a result, the functionality of the amplifier is reduced. To eliminate such phenomena, it is necessary to install a drive in the car. It is an electrolytic device with a large capacity. Connected in parallel with respect to the power circuits on the amplifiers. The resistance of the equipment is very low, and the current is transferred to the amplifier at lightning speed. Thanks to this, the occurrence of subwoofer malfunctions is excluded. Just as quickly, the capacitor is recharged again and “gives” a portion of the current back.
So, what is a subwoofer capacitor for? In simple words, we can say this: the device accumulates and quickly transmits electricity. In technology, this function is used to improve the sound of a car radio.
Capacitor
There is an opinion that the current storage prolongs the life of the battery or facilitates its operation. And some car owners install devices based on this consideration. But this is a proven myth! The storage device does not produce energy. It only accumulates electricity and delivers it to the consumer.
general information
The best capacitors for acoustics
So why do you need a capacitor? As you know, the price for it is not small and not all motorists, even lovers of good sound, want to cut their budget once again. On the other hand, every music lover sooner or later acquires a powerful speaker system or brings it to perfection. This is very good, but the more powerful the system, the more energy you give it.
Note. The battery is not capable of delivering such energy, as a result of which a drawdown occurs (what this means is described in detail below). The drawdown is expressed by the fact that the car’s headlights begin to “blink,” the amplifier’s power drops, and the bass coming from the subwoofer, which was previously clear, becomes “blurry.” In some and especially severe cases, a sharp drop in amplifier voltage leads to clipping, which can damage the speakers.
What types of automotive capacitors are there?
Today, many different capacitors for cars are already produced. From the simplest and cheapest models, to elite and expensive ones, with a large capacity of 20F. Such capacious installations are used in powerful equipment that has a distributor and has the ability to connect more than two amplifiers at the same time.
Automotive capacitor
The choice of device depends on several factors. Basically, you need to consider the power of the car's battery. Never buy equipment if it looks questionable. Capacitors have the “property” of exploding. And even the slightest violation of the integrity of the structure can lead to an explosion.
When inspecting the device in a store, you need to pay attention to the presence of protection on the terminals. They protect the system from accidental short circuits. It is also important to study the ease of connection and installation.
Automotive capacitor
Why do you need a capacitor in a car?
Signal connection diagram via relay
If your vehicle's headlights are flickering, the speakers are wheezing, and the drives are malfunctioning, this means that the overall power system is not working well. Most likely, your vehicle's generator is not always able to fully provide the required amount of voltage that is required for the correct operation of all elements and components of the machine.
If the system's supply voltage changes by just a few volts, it will immediately affect the speakers, spoiling the overall listening experience. If the headlights flash in time with the bass of the speakers, it means the car components are not receiving stable voltage.
If the supply voltage in the car system changes by only a few volts, this will immediately affect the speakers
You need help, and the first solution is to install a capacitor on the car.
What equipment capacity is needed?
There is no exact formula here. Many follow this rule: 1 kW. from the power of the amplifier must correspond to 1 F of the capacitor capacitance. This is normal and most users purchase the design precisely for this reason. For example, if your car has an audio system with a power of 2 kW, then you need to purchase a drive with a capacity of 2 Farads. But experts recommend choosing a device with a large supply of capacity.
Subwoofer amplifier and capacitor
Some models have built-in voltmeters. They control the system voltage level. Devices with voltmeters are more expensive.
How to choose
An electrical capacitor is a special device with two strips that accumulates, stores and transfers current charge to connected nodes. Its design consists of plates with dielectric insulation. The main property of the product is capacity, which indicates the amount of energy that is obtained per unit of time. This parameter is displayed in farads (F).
Among the variety of capacitors, the maximum capacity is characteristic of electrolytic models or more modernized types - ionizers.
To simplify the selection of a capacitor for an amplifier in a car, you need to get a general idea of what happens in the vehicle network when you start a car radio with a power of 1 kW or more at low frequencies. With simple calculations, it is possible to determine the following - current consumption reaches 100 A. However, the load becomes uneven, and peak values are noticed during bass hits. Voltage surges are associated with two phenomena:
- The internal resistance of the battery, which limits the current output.
- Exposure to resistance from wires that contribute to voltage drop.
The battery and capacitor have some similarities. They are designed to accumulate and release electrical energy, while the second node copes with this task faster than a battery. This property determines the scope of its use.
The capacitor is connected in parallel. If there is a sharp jump in current consumption, the resistance inside the battery drops sharply. At this time, the condensing element is activated, which transfers energy, compensating for the drop in power.
When choosing a part, you need to consider the power of the subwoofer. In addition to complex calculations, you can apply a simple rule: every 1 kW of power requires 1 F of capacity. Exceeding this will only lead to positive responses. In this case, the operating voltage should vary from 14-18 V. Individual capacitors are equipped with a special indicator that simplifies their use, as well as electronics for monitoring the charge.
This is due to the principle of its operation and the following features:
- The device acts as a filter for network voltage surges that appear when switching loads or interacting with electronic devices. Its presence has a positive effect on the operation of all parts.
- The capacitor suppresses surges when starting or deactivating on-board voltage consumers, which is why the generator operates without failure.
- When the car starter starts, the condensing unit provides it with additional assistance by transferring a voltage charge to the on-board network. This feature will be especially useful in winter, when the battery cannot normally transmit electric current.
How to install a drive in a car
Installation is usually carried out close to the amplifier. This prevents the amplitude of the electricity from decreasing. Since the connecting wires always produce resistance due to the low resistance of the capacitor. It is important to know that a distance of no more than 60 cm should be maintained from the amplifier to the capacitor. The smaller this gap, the better the installation.
Connecting a subwoofer
Some people mount the structure directly on the amplifier. It is convenient, practical and neat looking. Doesn't take up much space in the cabin. But there are other ways to arrange the system. For example, many car enthusiasts have gotten used to placing the amplifier in the luggage compartment, on the side of the wall. And the capacitor is on the opposite wall. It looks nice, but from a technical point of view it is not practical, since the distance is too large.
An important point: when installing a current storage device, it is not allowed to connect it uncharged to the positive and negative power wires. Because with such contact, the device will be “powered” by current from the battery, and this leads to burning of the fuse.
To avoid such troubles, manufacturers began to attach special circuits to their products, according to which the capacitors are charged gradually. If such a circuit is not available, then you need to charge the equipment in advance through a 12-volt light bulb. If the light goes out during installation of the device, it means it is sufficiently charged.
Capacitor for a subwoofer in a car
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Autocapacitors have one serious drawback: the ability to self-discharge. This type of electrical devices is bad for your car battery. Especially if there are a lot of them and it’s cold winter outside. To solve this problem, there are many devices on the market that are connected only when voltage appears at one terminal.
Capacitors from popular companies are equipped with a very convenient function, for example, installing a voltmeter. This is necessary for visual instrumental monitoring of voltage sags.
When connecting to the starting system, be sure to check that there is no voltage on the starting wire when parked. If there is no potential on it, then the car's network will be blocked from the capacitor. It is very easy to perform manual switching yourself. To implement this, you just need to use a relay. The switch can be placed in any place where it is convenient.
Connection recommendations
- The system can be connected to circuits of any power. Even in cases where one amplifier built into the head unit is working. But when installing a capacitor in an audio system equipped with an external amplifier, the first step is to start with the minimum system power (from 250 to 300 W).
- Such a device does not have to be connected only to a sound system that has a special battery. It’s just that such a “sonic” battery can quickly supply current and just as quickly unload the car’s network.
- If you are going to connect the device yourself, it is better to have protective circuits. Also, you should have on hand devices that monitor the state of the on-board network.
Be sure to follow the diagram when connecting elements. It has visual drawings showing the location of electrical circuits. All important information is also present on the diagram.
Selecting a starting capacitor for an electric motor
A modern approach to this issue involves the use of special calculators on the Internet that perform quick and accurate calculations.
To carry out the calculation, you should know and enter the following indicators:
- Motor winding connection type: delta or star. The capacitance also depends on the type of connection.
- Engine power is one of the determining factors. This indicator is measured in Watts.
- Mains voltage is taken into account in calculations. As a rule, it can be 220 or 380 Volts.
- Power factor is a constant value that is often 0.9. However, it is possible to change this indicator during calculation.
- The efficiency of the electric motor also affects the calculations performed. This information, as well as others, can be found by studying the information printed by the manufacturer. If it is not there, you should enter the engine model on the Internet to search for information about what the efficiency is. You can also enter an approximate value, which is typical for such models. It is worth remembering that efficiency may vary depending on the condition of the electric motor.
Such information is entered into the appropriate fields and an automatic calculation is carried out. At the same time, we obtain the capacity of the working condensate, and the starting condensate should have an indicator 2.5 times greater.
You can carry out such a calculation yourself.
To do this, you can use the following formulas:
- For the star winding connection type, the capacitance is determined using the following formula: Cр=2800*I/U. In the case of a triangle connection of the windings, the formula Cр=4800*I/U is used. As you can see from the information above, the type of connection is the determining factor.
- The above formulas determine the need to calculate the amount of current that passes through the system. For this, the formula is used: I=P/1.73U?cos?. For the calculation you will need engine performance indicators.
- After calculating the current, you can find the capacitance indicator of the working capacitor.
- The starting one, as previously noted, should be 2 or 3 times higher in capacity than the working one.
When choosing, you should also consider the following nuances:
- Operating temperature range.
- Possible deviation from the calculated capacity.
- Insulation resistance.
- Loss tangent.
Usually, the above parameters are not paid much attention. However, they can be taken into account to create an ideal electric motor power system.
Overall dimensions can also be a determining factor. In this case, the following dependence can be distinguished:
- Increasing the capacitance leads to an increase in the diametrical size and outlet distance.
- The most common maximum diameter is 50 millimeters with a capacitance of 400 µF. At the same time, the height is 100 millimeters.
In addition, it is worth considering that on the market you can find models from foreign and domestic manufacturers. As a rule, foreign ones are more expensive, but also more reliable. Russian versions are also often used when creating an electric motor connection network.
Ionistors
Ionistors are fashionable substitutes for storage devices, something that most music lovers often carry in the trunk; they differ from capacitors in the following parameters:
- Large energy losses
- Huge resistance
- They release charge much slower than drives
- They cost several times less than drives of the same capacity
- The optimal operating time of the ionistor is: 1 second/83 cool.
Checking the ionistor
The instructions recommend checking the ionistor to understand whether it works and how it works:
- Connect the ionistor to the speaker system with power drawdowns
- Start the engine and observe, if the voltage at its terminals increases, then everything is in order for now
- Increase the volume and notice how the voltage drops from 13 to 10 volts
Note: This means one thing: at the first hit of subwoofer power, the charge drops and the ionistor turns into an extra component in the power system, since it is active and useful when its charge is higher than the voltage inside the network.
- Car audio enthusiasts call this situation a drawdown ; it can become much greater if you use thin and low-quality wires made of cheap copper-coated aluminum in the power system
- In this case, the cable sag is added to the standard sag.
Note: It is worth knowing what the consequences of cable sagging are. The reason is that a sharp increase in consumption causes an increase in reactance.
And the faster and more the user wants to take energy through the cable, the more the cable will interfere with this (especially if it is thin and very long). The problem from a cheap and low-quality cable is reflected in the ionistor, which, after discharge, will no longer be able to accumulate energy again, so decide for yourself
How to connect a capacitor to a subwoofer
Installing a capacitor is not a complex procedure, but when performing it you need to be careful and follow some rules:
Figure 1 illustrates the connection of a capacitor to a subwoofer.
How to charge a capacitor for a subwoofer
To connect to the car's electrical network, an already charged car capacitor should be used. The need to perform this action is explained by the properties of the capacitor, which were mentioned above. The capacitor charges as quickly as it discharges. Therefore, at the moment the discharged capacitor is turned on, the current load will be too high.
If the purchased subwoofer capacitor is equipped with electronics that control the charging current, you don’t have to worry; feel free to connect it to the power circuits. Otherwise, the capacitor should be charged before connection, limiting the current. It is convenient to use an ordinary car light bulb for this, turning it on against the power supply circuit. Figure 2 shows how to properly charge large capacitors.
At the moment of switching on, the lamp will light up at full intensity. The maximum current surge will be limited by the power of the lamp and will be equal to its rated current. Further, during the charging process, the glow of the lamp will weaken. At the end of the charging process, the lamp will go out. After this, you need to disconnect the capacitor from the charging circuit. Then you can connect the charged capacitor to the amplifier's power supply circuit.
If after reading the article you still have questions about connection, we recommend that you read the article “How to connect an amplifier in a car.”
Why do you need a separate battery for car audio?
For stable operation of a car amplifier, the on-board network must have a voltage of 12.8 - 14 W.
Car owners who decide to improve the sound quality and buy the necessary equipment are often disappointed, never achieving a result, no matter how hard they try to configure the system. The reason for this is voltage sags. What causes them: Unsuitable power cables, power distributors, fuse holders or batteries are used.
For stable operation of a car amplifier, the on-board network must have a voltage of 12.8 - 14 W. This indicator will easily “sag” (for example, when playing bass) if the power system has insufficient current conductivity. During drawdowns, the power of the amplifiers drops, which reduces the sound quality of the audio system.
In this situation, you can “blame” the standard battery. Due to its high internal resistance, it cannot supply enough electricity to the amplifiers to process the incoming audio signal. Drawdowns also occur due to its distance from the amplifiers (current travels longer through long cables).
The second point is that the task of the “native” battery is reduced to providing energy to the on-board network and the starter. There is not always enough of it anyway; there are cars with “tired” batteries that are undercharged.
And if you add car audio, which also requires power, the battery may even die out of the blue, and then it won’t be possible to start. After 2–3 deep discharges, the power source can be discarded.
Pros and cons of two batteries in a car
If there are two batteries, careful monitoring of the charging current and state of charge is required.
As for the advantages, firstly, this is a separate power source for:
Secondly, a separate battery for car audio, because the sound system requires a decent amount of energy. And when the engine is idling, the battery is not recharged, so you may be able to listen to music at a picnic, but not for long.
Usually, instead of a similar standard battery, a gel battery is used for car audio. It is durable, without the risk of plates shedding (when delivering critical current).
Manufacturers and costs of subwoofers
We've sorted out the hubs and types of subwoofers for cars. Now let's pay attention to the cost and manufacturers. Prices from different manufacturers may vary significantly. The cost in this case depends on the company, power, diffuser diameter and other characteristics.
Subwoofers from ALPINE, Pioneer, MYSTERY, and Prology are extremely popular among car owners. The cost of budget models varies from 2 thousand rubles. Among them:
- PROLOGY WOWBOX1200 (3000 rubles).
- PROLOGY WOWBOX1000 (2500 rubles).
- DRAGSTER DER210 (4000 rubles).
The average price category includes subwoofers from 7,000 to 12,000 rubles. These are the models that most car enthusiasts choose. Among them are the following:
- CADENCE MBX-12A (7500 rubles).
- CADENCE XBP-122 (10,000 rubles).
- ESX SXB-302 (12,000 rubles).
There are also more expensive, powerful, high-quality and reliable subwoofers for cars. Their cost is calculated from 15 thousand rubles. These are models ALPINE SWD3000 and FOCAL BOMBA27V1.
How to connect a capacitor to a subwoofer
Installing a capacitor is not a complex procedure, but when performing it you need to be careful and follow some rules:
Figure 1 illustrates the connection of a capacitor to a subwoofer.
How to charge a capacitor for a subwoofer
To connect to the car's electrical network, an already charged car capacitor should be used. The need to perform this action is explained by the properties of the capacitor, which were mentioned above. The capacitor charges as quickly as it discharges. Therefore, at the moment the discharged capacitor is turned on, the current load will be too high.
If the purchased subwoofer capacitor is equipped with electronics that control the charging current, you don’t have to worry; feel free to connect it to the power circuits. Otherwise, the capacitor should be charged before connection, limiting the current. It is convenient to use an ordinary car light bulb for this, turning it on against the power supply circuit. Figure 2 shows how to properly charge large capacitors.
At the moment of switching on, the lamp will light up at full intensity. The maximum current surge will be limited by the power of the lamp and will be equal to its rated current. Further, during the charging process, the glow of the lamp will weaken. At the end of the charging process, the lamp will go out. After this, you need to disconnect the capacitor from the charging circuit. Then you can connect the charged capacitor to the amplifier's power supply circuit.
If after reading the article you still have questions about connection, we recommend that you read the article “How to connect an amplifier in a car.”
Subwoofer storage, myths and reality
I won’t overload you with technical concepts and terms; I’ll write generalized useful information from the Internet + knowledge from personal experience.
So, let's go. Anyone who has a subwoofer in their car has probably wondered “what is a storage device (capacitor) and why is it needed at all? Maybe you can listen to music without it.” Let's figure it out.
In fact, as a storage device, especially a budget one, nothing more than
an ionistor - a super capacitor, but it sounds impressive :)) in fact, this is a device that is capable of quickly accumulating and releasing energy, it is used at high current loads, that’s in a nutshell. The Internet is filled with all kinds of information, in particular, “advisers” predominate - people who have forgotten or do not know the elementary school physics course or who do not understand what they are talking about at all. Please remember two axioms:
