12-volt devices in the car

Hi,

Is there a "ready-made" solution to prevent 12-volt devices from being damaged by 14.4 volts?

Specifically, this refers to a Linksys WRT54G or a Netgear WN802Tv2.

Or should I just attach a 78S12 with a large heatsink to it?

m;

You can buy a DCDC converter that specifically outputs 12V.

We use it in the development of sensitive measurement systems in vehicles.
Unfortunately, such a converter is quite expensive.

What do you intend to do with it?

You can certainly build something like this yourself and use a properly sized voltage regulator. I built something similar, but for the increasingly common 5V devices that are powered or charged via USB cables. The USB port, which is demonstrably conveniently located on the top of the dashboard support and is used to play music from USB sticks, is no longer powered by the meager 5V supply from the car radio, but now has its own "power supply" that can also meet the power demands of a charging navigation device or my Pure Highway (a DAB+ receiver).

For USB and the required 5V, I found something at Pollin.de back then that, with a slight modification, could be used for my purposes. It has an input of 10...15V and an output of 5V with a maximum current draw of 2A. However, it should be installed with good ventilation if you really want to draw that much current. I mean, I wouldn't have spent more than 4 euros.


EDIT: It should be more powerful for you, right? At least, that's what I'm reading from your post. Take a look at the article number 721 628 on Pollin!

voodoo wrote:

What do you intend to do with it?

I was thinking about this:

dieselmartin wrote:

Specifically, this refers to a Linksys WRT54G or a Netgear WN802Tv2.

m;

Oops... I must have missed that.

So, in this case, the DCDC converter is naturally a little oversized .
I would use a standard, adjustable car power adapter for laptops.
z.B. http://www.priz24.de/-hama-kfz-universal-netzteil-fr-notebook-120-watt-schwarz-s-2-p-308878.html

or

http://www.tradoria.de/produkt/120-watt-universal-kfz-netzteil-fuer-notebook-496668311.html?cid=google_base&utm_source=preisvergleich&utm_medium=referral&utm_campaign=googlebase-2010-07

That was my idea too! Be careful, not every car power adapter for a laptop can output 12V! Most start at 15V, which is exactly what he didn't want. The item I selected in my previous post (see above!) should hopefully meet the requirements.

voodoo wrote:

ups... I had overlooked that. So, in this case, the DCDC converter is naturally a little oversized . I would use a standard, adjustable car power adapter for laptops. z.B.

or

http://www.priz24.de/-hama-kfz-universal-netzteil-fr-notebook-120-watt-schwarz-s-2-p-308878.html

Unfortunately, they are all outputting at least 15V.

Hatfahrer's http://www.tradoria.de/produkt/120-watt-universal-kfz-netzteil-fuer-notebook-496668311.html?cid=google_base&utm_source=preisvergleich&utm_medium=referral&utm_campaign=googlebase-2010-07{MARKER} seems to fit.

Thank you.http://www.pollin.de/shop/dt/MTczODcyOTk-/Computer_und_Zubehoer/Hardware/Netzteile/Laptop_Stromversorgung_fuer_KFZ_80_W_mit_USB.html

Hi Martin!
I got this http://www.amazon.de/gp/product/B002PZGTDK back then for my WRT54G3G, and it worked wonderfully. The WRT54G3G model is no longer available, but the power adapter is still around.

If you want, I can double-check to see if the 12V measurement is correct.

However, there are also some negative reviews about the product.

Hi Max,

What happened to the WRT54G3G?
Did the power supply fry it ?

m;

No, it was replaced with a Netgear MBRN3000. EDGE wasn't working with the Linksys, and that was important in this case. The Linksys device was also only occasionally in the car (during vacations, etc.).

And nowadays, that's almost become unnecessary, thanks to tethering.

Can the MJ11 FSEs also be tethered?

Tethering is not really interesting for tourists in France; rather, Wi-Fi repeaters and LARGE antennas are .
If the WRT is already in the car (a 13-hour journey), it can also run on 230V again at the destination.

m;

There are some devices that can support WPAN, but I don't know exactly which ones. And with some older devices, you can also establish a connection via Bluetooth (DUN ->
I haven't tried either of them yet. Tethering was specifically related to smartphones, and vacations were more about meetings and similar activities, where one is often on the move and not necessarily near a 230V power outlet. http://en.wikipedia.org/wiki/Bluetooth_profile#Dial-up_Networking_Profile_.28DUN.29).

I ordered a universal laptop power adapter directly from a company in mainland China through a platform like eBay. It uses "miniature fuses" that, instead of containing a physical fuse element, each have a resistor molded inside, allowing it to be adjusted to almost any required output voltage between 12 and 28 V. Although it's rated for a maximum of 42W, it worked perfectly with various different laptops. It was a bit underpowered when used with my "large" laptop if the battery was installed and completely empty. In that case, the power adapter wouldn't turn on. My small netbook (LG X110 3G+) works perfectly with it. I measured it again a little while ago, and it showed 12.25 V under load, and 13.1 V without a load.

The Pollin product should be powerful enough for all eventualities, and in my opinion, it was also reasonably priced. However, I would still take a look at online marketplaces and specifically search for sellers from mainland China, Taiwan, or Hong Kong. If it's not urgent, you should know that there may be a waiting time of up to 2 weeks.

You could also take a look at Dealextreme.com if you're looking for products from China.

Hi Martin,

Most power supplies are either boost converters, which are those that can only increase the voltage, or buck converters. So, those that can only reduce the voltage.

Buck-boost converters are less common in these applications.

For all types, you should check if you need galvanic isolation! As long as you don't connect anything wired to the access point, it doesn't matter. But if you have a laptop connected with a cable, and that laptop is also connected to the vehicle, then you can get very bad equalization currents.

The question is: is it okay for the voltage to the access point to drop during startup, or does it need to remain stable?

What would definitely work: boosters, like the ones used in RVs. These are typically galvanically isolated and have an adjustable voltage (default: 13.8V output, 8-16V input).

I have a Carbest Boost 8A [url][/url] whose output voltage is adjustable to 12V, and it is also galvanically isolated. I bought it on eBay for €50 including shipping. It might be "a bit" too large for your application.

Greetings.
Guste.http://www.reimo.com/de/82180-carbest_power_booster_8a/{MARKER})

Well, my NAS could still be used.

Then, 1-2 SSDs will be installed, and that should provide enough movies for the RIO (which is the German abbreviation for "WSO," meaning the officer who is present but not allowed to fly himself and operates the controls ). (300 MB per movie, optimized for the iPhone 3GS display and looks great on the iPad).
Or I could attach the NAS to rubber bands and risk damaging it (specifically, the hard drives).



m;