USB socket in the car. Do-it-yourself stationary USB connector in a car How to connect a USB connector in a car

On sale there is a large assortment of automotive USB connectors that connect to the car's cigarette lighter. But this is not always convenient, besides, with such a considerable number of USB devices that have become so closely integrated into our lives, it would be quite nice to have a stationary connector in the car that does not take up space in the cigarette lighter socket. One of the ways how this can be done will be discussed in this article.

Required materials and tools:
- Standard USB connector with 12 volt power supply;
- A piece of plastic;
- Carbon film;
- Metal clips and coupler;
- Soldering iron with solder;
- Knife;
- Screwdriver;
- Sandpaper.

Step 1. We disassemble the connector.

Of the standard connector, we need only its electronic part, the case is not needed. Therefore, we boldly disassemble it and get the board.

Step 2. Front panel.

Since the socket will be built into the torpedo, there is no need to make the entire housing for the electronic part, you can limit yourself to only its front side. We cut out the piece of plastic we need in size, inside it we cut a rectangular hole for the connector itself. If there is an LED indicator, then we make a hole for it. We pass the edges of the plastic with sandpaper.

To improve the appearance, you can stick a piece of carbon film on top.

Step 3. Assembly.

Using a metal tie, the board with the connector is attached to the inside of the plastic socket. It is desirable that the connector enters the socket with a minimum gap.

Metal clips are attached to the back of the plastic socket:

The socket is installed in the place allotted to it and fixed with clamps:

And the device is ready to go:

This charge is remarkable in that it is not inserted into the cigarette lighter socket, but is installed instead of it or crashes into the panel. When buying autoloading not for $1 (as last time), you expect to get something more or less normal - I will study it in detail ...

The rubber plug covers not only the USB sockets, but also the blue LED, which is rather a plus.
Installation hole 29mm, installation depth with connection terminals 65mm

Before loading the charger, it was decided to disassemble it at the beginning in order to have an idea about the installed components and not burn it prematurely.
The charging is disassembled without global destruction - the back bottom is slightly glued and removed with a scalpel.

The LED suddenly turned out to be rectangular.
Traditionally, I drew a charging scheme.

Assembled charger based on CX8505 (Step-Down 30V 3A 350kHz Up to 95%)
It is noteworthy that the converter is synchronous.

The working frequency of the inverter is really 350kHz

The amplitude of the output ripple at a load of 2A is only 40mV

Now more about the problems...
There is no built-in fuse - you will have to put an external 1.6-2A on the connection wires.

There is no protective zener diode (suppressor) at the output, i.e. upon breakdown of the microcircuit, the full on-board voltage will go to USB

There are no filters - the occurrence of interference is not ruled out. It is advisable to put a filter on the input power.

The input capacitor HUAHONG CD110 100uF 50V (measured 90uF 0.6ohm) works with overcurrent.
In accordance with the specification, an effective operating current of only 210mA is permissible for it, but in reality at a load of 2A, an effective current of more than 1A flows through it, while it naturally heats up a lot.

The manufacturer had to put a normal LowESR capacitor 330uF 35V there.

The 85μH inductor is wound on a D10.2 / 5.08 / 3.96 (-26) core with a 0.6mm 46 turns wire, which does not work efficiently at such high frequencies, so the manufacturer had to greatly increase the inductance to reduce core heating. It would be optimal to use a ring made of high-frequency material (for example -52).

The capacitances of capacitors C1 and C2 are for some reason mixed up in places (compared to the official specification).

Examination
No-load current at input 7mA
Open circuit voltage at the output 5.23V (by USB tester 5.17V)

Open heating test at 22°C ambient temperature
- Current 2A, inductor 71°C, capacitor 62°C, chip 65°C (actually even higher, because the case is small).
When closed, the heating of the elements will increase significantly, but it should work normally.
- Current 2.5A, inductor 89°C, capacitor 75°C, chip 80°C
When closed, the elements will overheat and charging will not withstand such work for a long time.
- Current 3A temperatures exceeded one hundred and testing was terminated.
- Current 3.5A very briefly without temperature measurement
- Even more current does not pull - at 3.6A, the current limitation is triggered and the voltage immediately drops.
- Short-circuit output current - 5.2A (short-term)

Checking the heating of the closed case at an ambient temperature of 22°C
- Current 2.1A maximum case temperature 48°C
- Current 2.5A maximum case temperature 59°C

Measurement of efficiency, voltages were recorded directly on the charging contacts

An attempt to raise the efficiency of the converter to the declared 95% by replacing the inductor and input capacitor was unsuccessful - the efficiency increased noticeably only at currents above 2A, which does not make sense in charging at 2.1A.
As a result, I replaced only the input capacitor with 470uF 25V (to reduce its heating), put a 1.5KE6.8 suppressor on the output and fixed the parts with sealant.

Now more about connection
One of the assistants

Included are terminals for wire 2.5kv mm (blue). This is too thick a wire for such a charge - with a large margin, 0.75 sq mm is enough

It’s impossible to just take and clamp this wire into the terminals, because. they just won't hold up.
But there is one trick - to use additional pin tips of the right size (in this case 0.75)

The wire was crimped first with them

Then he clamped them into the terminals

To indicate the polarity, I additionally put a red heat shrink on the positive wire

And fixed the insulation

Put on a ferrite noise filter

Assembled

Or so

So that the ferrite does not beat against the panel, I wrapped it with a soft tape for harnessing

Added a fuse holder on the other end

Now you can put in the car instead of the cigarette lighter socket or cut a new mounting hole.
I did it myself...
Choose a location for installation

Removed the protective cover of the gear knob

Marked the place with the removed nut and marker

Drilled out along the contour

I trimmed it with a semicircular file, cleaned the sawdust with a vacuum cleaner, cut off the plastic interfering from the inside with a knife (not yet cut in the photo)

Installed and tightened the nut

Connected in parallel with the standard cigarette lighter socket
I usually solder the connections, but here the currents are small and banal twisting works fine

Orthodox blue electrical tape refused to stick in the cold, had to wind the bourgeois

And lit

Fastened with zip ties in the right places.

Ready

It took 2 hours
If something is not clear - ask.

Advantages: appearance and workmanship, good efficiency, honest 2.1A.
The disadvantages are described in the article.

I plan to buy +106 Add to favorites Liked the review +134 +262

Until recently, a USB connector in a car was considered almost a luxury. There is no such connector in many modern models, not to mention cars manufactured 10-15 years ago. In this article I will tell you how to get 5 V for the USB connector from 12 volts of the on-board network.

Many people install various devices powered by a cigarette lighter in their cars - a DVR, a GPS navigator, and from time to time you need to connect a charger for your phone. And since there is only one cigarette lighter socket, they buy a splitter, but this is not a way out, the wires stretching through the dashboard not only distract and interfere, they can cause an accident.

As a rule, all these devices are designed for voltage of 5 V (standard voltage of the USB interface), and a converter from 12 to 5 volts is contained in the plug of each of these devices. I suggest installing one 5 V power source in the car and powering all the necessary devices from it via USB, mini USB connectors.

Update from 07/30/2015.
The information from the article is still relevant now, but an alternative solution has appeared - ready-made USB adapters with a connection to a 12 V network. This is not about cigarette lighter adapters, they were on the market at the time of the first publication, but about independent converter devices.

The device consists of two modules. The case with an external thread is made in the form of a cigarette lighter cartridge and a USB adapter with two connectors is inserted into it. The manufacturer claims the following characteristics:

Output voltage: 5V;
Output current: 3 A.

Buy on AliExpress

Unlike the previous version, this device has a one-piece design and backlight with a choice of colors: red, green, blue, orange, white.

Declared characteristics:

Input voltage: 12 - 32 V;
Output voltage: 5V;
Output current: 1A; 2.1 A.

Buy on AliExpress

The adapter has a removable flange with screw holes, which does not add aesthetics to it, but it can be installed without a flange. Please note that USB connectors have different output current. Specifications:

Input voltage: 12 - 24 V;
Output voltage: 5V;
Output current: 1A; 2.1 A.

Buy on AliExpress

Structurally, the adapter differs from its round counterparts, thereby complicating installation. But outwardly it has a pleasant appearance and should fit well into the interior of the car. Technical specifications:

Input voltage: 12 - 24 V;
Output voltage: 5V;
Output current: 3.1A.

Buy on AliExpress

These are the USB adapters currently available. They are easy to install. You can connect it to the cigarette lighter power circuit and, please, we have a full-fledged USB connector in the car. But there is a small nuance - these adapters do not have a separate (cable) 5 V output. This is important for permanently installed devices, for example, a DVR. Thus, the old part of the article has not yet lost its relevance. Reading!

Modellers use UBEC to power aircraft, auto, and ship models. What it is?
UBECUniversal battery elimination circuit- This is a switching on-board power supply device, the output of which is 5 or 6 V.

The choice fell on TURNIGY 3A UBEC with interference suppression. Bought from HobbyKing. Also available on Parkflyer.

The TURNIGY 3A UBEC is thermally protected. The shielded housing serves to suppress interference. It has a high efficiency - 92%, the minimum difference between the input and output voltages is only 1.22 V.

The heart of this converter is the MP1593DN chip, the datasheet can be downloaded at the end of the article.

Specifications of the TURNIGY 3A UBEC converter:

Input voltage: 5.5 - 23 V;
Output voltage: 5V or 6V, set by switch;
Output current: 3A;
Dimensions (LxWxH): 51x16.6x8.5 mm;
Weight: 11.5 g.

This is how I received it (I already opened the bag, I could not resist):

The kit includes instructions and, in fact, UBEC itself. For comparison, I put a USB flash drive next to it:

The jumper has already been set to 5 V, there is a marking on the board how to switch the output voltage to 5 or 6 V. Let me remind you that we need 5V! The following two photographs show this marking. And also what is hidden under the screen. Thanks for these photos to Kirill Rodionov from the park flyer, I did not have to disassemble my converter.

For additional protection, if the converter suddenly fails so that the output does not turn out to be 12 V, I installed a zener diode 1N4734 (datasheet at the end of the article): stabilization voltage 5.6 V; dissipation power 1 W, stabilization current 45 mA. Here is a set I bought on ebay:

The zener diode is connected to the circuit parallel to the output, with the cathode to the plus "+". The cathode on the zener diode is marked with a black stripe:

We solder the zener diode, the red wire “+”, to it with a strip. Additionally, I soldered short conductors with a cross section of 0.5 mm 2, then it will be easier to wire the circuit from them. Pre-dressed pieces of heat-shrinkable tubing:

After shrinking individual pieces and a common tube dressed on a zener diode with a hairdryer:

Since I need power for the DVR and for the phone charger, two connectors are needed - a mini USB plug and a USB socket.

I found a wonderful adapter on ebay - USB A Female to Mini USB B 5Pin Male left angle adapter. It has an angled mini USB connector on one side and a USB socket on the other:

With tears in his eyes, he cut it in half:

Due to the lighting, the photos were taken on different tables.

The red wire is positive "+" and the black wire is negative "-". Just in case, I checked according to the pinout of the connector:

I took the wire, taking into account laying it behind the decorative elements of the cabin. For the mini USB connector, the length of the wire is longer, because. The DVR is mounted on the top of the windshield. For a standard USB, the wire is shorter, I'll put it somewhere on the dashboard, I haven't decided yet.

I connected the wires, marked them so as not to get confused. Similarly, I put a heat shrink tube on each conductor and on top of one common one:

Here are the two cables:

Soldered, put everything together, observing the polarity. This is what the final kit looks like:

It remains only to install this design in the car, lay the wires and bring out the USB connectors in the right places. Be sure to connect through a fuse, you can through some regular from an irresponsible circuit.

Many DVRs have a function to automatically turn on and off when power is applied and when power is lost. It is very comfortable. Therefore, if you connect the converter to the cigarette lighter circuit, then this function will work, because. The power supply to the cigarette lighter depends on the position of the key in the ignition switch. But in this case, for example, charging the phone from the new USB connector in the car will not be very convenient, you need the ignition key to be in the lock.

If this problem is not relevant for you, connect UBEC to the cigarette lighter circuit. Otherwise, connect to a circuit that does not depend on the ignition switch, and in order to keep the function of turning on / off the DVR, use an additional relay:

The diagram shows an automotive relay in the general case, but it can be without a quenching diode and without normally closed contact 87a.

Summarize. The TURNIGY 3A UBEC voltage converter is ideal for organizing USB connectors in the car. It is made qualitatively, corresponds to the declared characteristics at an affordable price.

This converter provides 3 A at the output, which theoretically allows you to connect up to six devices to it. According to the specification for the USB interface, the maximum current consumed by the device should be no more than 0.5 A, for USB 3.0 no more than 0.9 A.

USB socket in the car. Do-it-yourself stationary USB connector in a car How to connect a USB connector in a car

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