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Classic car USB connector

JG Classics Administrator — Tue, 28 Mar 2023 22:40:45 +0000

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Classic car USB connector

Occasionally we need to have to connect some small device inside our classic car. It can be a socket for charging a phone, a portable GPS, or any (semi)permanently installed device.

Nowadays, many of these devices come with a USB cable that is used to power the unit. USB (acronym for Universal Serial Bus) is an interface that was designed a few years ago to transmit data between devices quickly and capable of supporting connections/disconnections while the devices are still running.

In addition to this functionality, the USB connectors incorporate a permanent 5V signal between pins 1 and 4. This means that from the 4 USB pins, the two in the middle are data (signal and ground) and the two at the end are permanent 5V.

The type of USB connector we probably don't want/can't have on our classic

The fact that this type of connector has become a standard, and the need to make things cheaper, means that a large number of low-voltage devices do not have their own power supply and are therefore designed to be powered through a USB socket (which, let’s say everything, also has the advantage that we have finally have get rid of the endless number of power supplies that each gadget came with and that where quite a nightmare).

The small problem with our classics is that there is something that – in general – we don’t want: we don’t want a cigarette lighter connector or similar inside the passenger compartment (for aesthetic reasons).

To avoid this, there are still adapters in the form of a small box that can be discreetly installed inside. But they also have an aesthetic problem: The USB outlets are aerial, so it is difficult to integrate them somewhere inside the car without being visible. I am referring to a device like this one:

But apart from the aesthetics, there is something else: if our classic car has a 6V electrical installation, 99.9% of these adapters work only at 12V input. So cars with 6V electrical installation are left out..

In my case, I needed to install a small speedometer on my Renault 4CV. There are some models that are very small, operate by GPS and, if installed properly, can be hidden, “removable”, or in a discreet place that is only visible to the driver and does not detract from the interior of the vehicle. In the case of the 4CV, the need came to have something more accurate than the speedometer on the dashboard, which, despite having changed the cable from the gearbox to the instrument, has a certain inaccuracy.

A USB power supply with input between 5 and 24V on a 2.5 cm board.

Well, we finally located this little wonderful product: It is a mini circuit (measuring 2.5cmx1.5 cm) with USB socket and the best of all: it supports any voltage input between 5 and 24V, delivering 5V stabilized to the USB output.

The best thing: the price. As of the date of this article (March 2023) the device costs 0.68 euros + shipping (calculate between 1 and 2 euros for shipping).

In my case, the tests I have done on it have been satisfactory. These are the ones I have made:

Powering the above speedometer: one quarter ampere of consumption in the maximum case.
Powering a cell phone in fast charge: 0.5 Amps if the device received 12V input. And about one ampere if it received 6V.
Change the input voltage (I tested it with a lab power supply) to see the circuit was able to keep the output of the usb connector stable: as far as I have tested, between 5 and 15V the device still provides stable signal. Below 5V input, the device does not work and does not deliver signal to the output. But in the mentioned range, I have been able to prove that it works (I insist : changing the voltage in real time).
in real time
without disconnecting anything)

These photos are the monitor of a laboratory power supply that has been used to test the circuit by simulating different input voltages. The voltage (in yellow at the bottom left of the source display) is the input voltage to the power supply. The amps read at the bottom right of the source display is the current passing through depending on the load of the connected USB device. In the case of the 0.05 amp consumption, it is the small GPS speedometer (in standby configuration, it will probably consume a little more in operation). The following with half and one ampere of consumption respectively correspond to a cell phone in fast charge feeding the adapter with 6 and 12 volts respectively.

As I mentioned, we were able to verify that the device is tolerant to changes in input voltage, even sudden changes, without impacting the stability of the output signal. We also verified that up to 5V the input signal can be lowered without affecting operation. At less than 5V input, it stops. In any case, this adapter is NOT a DC booster. So if what you need is a direct current booster (for example, the classic 6V to 12V),
you can have a look at this entry

Where to buy it?

I found it on Aliexpress. It is obviously not the only supplier. But at least here you can find it in the following links:

On Aliexpress, under item number 1005005219811934
On Aliexpress, Under the description (you will get many items, this one among them): DC USB output charger 6-24V 12V/24v to 5V,
In this
link

Conclusion

Indeed, the miniaturization of electronics and the industrialization of manufacturing processes have made it possible to create devices with these features, of this size and at this price. A few years ago, such a stabilizer would have cost much more (probably 100 times the amount this one is worth) and in a much larger size. Think that we are talking about a board measuring 2.5cm long by 1.5cm wide that already includes the USB connector and costs less than one euro.

Due to the compact design, it can be installed anywhere in the passenger compartment and made invisible. It is up to the discretion of each person to find a place where the device is fixed and only the USB connection is visible.

One last comment: I have mentioned it several times here as “the device” but in reality it is not: it’s rather a circuit. So I would personally recommend that you either install it in a small box, or if that is not possible, you can drop a “turret” connector on the input connectors (the connectors are directly on the “top” of the printed circuit board, as you can see in the pictures) so you can either remove/replace it or attach it to a more mechanically sound installation.

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12V accessories in cars with 6 Volt installation

JG Classics Administrator — Fri, 07 Oct 2022 16:37:19 +0000

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12V accessories in cars with 6 Volt installation

And which converter to use to make them work smoothly:

Many of the vehicles manufactured before 1965 were equipped with a 6V electrical system. This includes many of the VW Beetle, the Renault 4CV, the first Citröen 2CV, the first series of the Renault Dauphine/Gordini and a list that gets bigger the further back in time you go. Even many of the English roadsters of that time, although they had a 12V installation (such as the MGA), this was achieved by mounting two 6V batteries in series.

In the event that you are the lucky owner of a classic car that comes equipped with a 6V installation, you may find yourself in the position of having to install an automotive accessory, which, perhaps, will operate at 12V. Some people goes for the project of converting the entire system of the vehicle to 12V, but perhaps you may not have the time, the opportunity, or simply the desire to do it.

The case I describe here happened to us with our Renault Dauphine Gordini. It is a 1963 unit manufactured by FASA-Spain, and was probably one of the last manufactured 6V cars of this model. To this unit, we installed the Blaupunkt Essen radio featured in this article. It is worth mentioning that there are radios from this period (approx. 1960-65) from brands such as Blaupunkt, Becker, and others, with voltage selector 6-12V as well as polarity selection for GROUND (ground)=NEG or GROUND(ground)=POS. But on this occasion, this 12V and negative-ground model was the one we were able to find.

The first test

For the radio installation, we tested with one of these compact devices found as “DC-DC 6V->12V converter” (or similar description). Something similar to this:

The result could not have been more dissapointing: The radio (still installed outside the car) generated a noise similar to the one of AC current, at such a high level that it completely masked the audio in the reception, -literally making it impossible to use-.

In reality, by the nature of their operation/design, these DC Boosters are native generators of electrical noise (somewhat similar to switching power supplies). So if what you want to power is a device that is not sensitive to electrical noise (e.g., a set of lamps, headlights, or the like), you will have no problem. But if you want to power something so sensitive to electrical noise as a radio, then you may have problems.

In our case, we did all possible tests: shielding the entire installation, testing different types and ground connections, installing anti-parasites in the power supply, and all the changes and tests we could think of: No improvement. In fact, I remember looking at the output signal of the converter through an oscilloscope and seeing that it was far from the flat signal you could expecte from a DC battery.

If you are interested in the subject, you can read this article about the noise associated with DC-DC boosters.

The solution

We found the solution on a Renault Dauphine forum in France. One of the forum members was talking about a STATRON® brand converter which worked very well. Since all the tests with the previous models of converters (several were tested) had not been successful, and on the other hand had been made in the Blaupunkt radio a significant investment in restoration by the company. Chrome London we didn’t want to lose, we decided to buy this converter. This is the device:

We installed it on our Dauphine to power both the car radio and two additional instruments installed on the dashboard (with their corresponding lighting). The result: Zero noise from parasites. Problem solved

You can buy it at AMAZON in Germany. It is around 100 Euros (at the date of publication of this post). At least for Spain, there is no shipping problem.

Installation:

In our Dauphine, the device is installed behind the glove box, on the passenger side. So that it is completely invisible. In this photo neither the inlet nor the outlet are connected yet. The device allows devices connected to the 12V output to use the same car ground without problems (I mention this because I had seen some converters that recommended NOT sharing the input negative with the output negative, making it quite complicated to use in a car).

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