OT: laptop im auto

[Translating...]

edit: aufgeteilt von https://community.dieselschrauber.org/en/viewtopic.php?t=4590
gremlin


Hi,

Gremlin hat perfekt recht. Das IBM-Teil braucht 16,8 Volt, mit einem EINFACHEN Ladekabel ists also nicht getan.

Es gibt dennoch ein KFZ-Netzteil dafuer, das kam irgendwas ueber 200 Euro.

Da ich aber den Inverter 12->230 geschenkt bekommen habe, ist das die deutlich einfachere Loesung. Nicht verstehen tue ich allerdings, warum VAG-COM dann nicht mehr funktioniert, denn ich halte es fuer sehr sicher, dass der Inverter galvanisch trennt, und beim Notebook-Netzteil weiss ich es.

Einziger Grund kann sein, dass der Schutzleiter des Netzteils (dieses Notebook hat ein Netzteil mit dreipoligem Stecker) beim Betrieb am Inverter nicht "geerdet" ist, wobei ich auch da keinen wirklichen Zusammenhang sehe. Ihr?


Jan

Einziger Grund kann sein, dass der Schutzleiter des Netzteils (dieses Notebook hat ein Netzteil mit dreipoligem Stecker) beim Betrieb am Inverter nicht 'geerdet' ist, wobei ich auch da keinen wirklichen Zusammenhang sehe. You?
Jan.

Sure...

It is called mass entanglement and scattering.

You now have two switching power supplies in series: on one hand, the DC/AC converter, and then the laptop power supply, which converts AC to DC. http://www.handykult.de/plaudersmilies.de/party/ylsuper.gif

Switching power supplies always leak current somewhere. If your laptop power adapter even has a ground connection, that's a good sign of this kind of issue.

The ground and the enclosure are usually connected via capacitors, meaning that high-frequency interference can flow to ground. However, this is no longer working...
It's quite possible that they could fail between the converters.

DC/AC converters are designed for resistive and inductive loads. However, a switching power supply represents a capacitive load. Consequently, most basic DC/AC converters will start to oscillate uncontrollably. My old 500VA UPS does this (when only the computer is connected) in approximately 2 seconds. Then, the outlet switch starts flickering as if it's possessed.
Try connecting a larger AC/DC power supply with a transformer to it.

Furthermore, your laptop is completely devoid of potential compared to a car... or maybe not.
It depends on the adapters being used.
In this case, you shouldn't encounter any problems (besides the ones mentioned above). However, some of the adapters have a connection through ground. While these adapters always include 100 ohms in that circuit, that might still be enough to cause interference. Just for fun, try using a high-impedance voltmeter and connect it to the vehicle's ground and pin 5 of the COM port. You might see anything from 0 to over 100 volts.
Okay, and also connect the ground pin of the laptop power adapter to the vehicle's chassis ground.

CU Gremlin.

Hi,

'Inverters can be a significant source of interference; it's difficult to make phone calls or listen to the radio near a cheap inverter. Given that VAGCOM interfaces are already quite sensitive and their performance can fluctuate, I would consider this as a possible cause.'

If your interface provides galvanic isolation (AND ONLY THEN!), then buy three single-cell batteries for testing purposes (alkaline batteries typically have around 16Ah).

Connect them in series and to the car's 12-volt power supply, then connect that to the laptop. It should start charging again and work. (12/13.8 V & 4.5 V = 15-18 Volts)


Since the monochrome printers are not very expensive at stores like Aldi, Lidl, and Penny, they could be a solution if you don't need to print very often.

Sure, I'll let you know when it's done.

Hello everyone,

Let's see if this works; I'm sending this from my mobile device. This is dieselschrauber.de and Wi-Fi from a Sharp Zaurus, while I'm sitting in a presentation...

Regarding the battery solution: It seems too risky to me because the voltage is not stable enough (13.8...14.4), and it's also not really regulated. Furthermore, and this is the most important point, my adapter does not provide galvanic isolation.

The issue with the interference caused by the inverter makes sense to me, although it seems to be an electrical problem since the computer is still running.

Connecting the ground wire of the power supply to ground seems like a good idea. The only question is whether the ground wire is connected to the secondary side (which I need to check), because otherwise there would be problems with the adapter.

Are there any other potential hazards if the cable isn't routed through the power supply unit?

Best regards,

Jan.

Connecting the ground wire of the power supply to ground seems like a good idea. The only question is whether the ground wire is connected to the secondary side (which I need to check), because otherwise there would be problems with the adapter.

Are there any other potential hazards if the cable isn't routed through the power supply unit?


Okay... I have Jeff's interface, which provides galvanic isolation, but the laptop is connected directly to the ship's power supply via a cigarette lighter adapter. So, there's no potential separation in that case...
The protective conductor is definitely not connected to the ground potential at a secondary point; that would be quite extreme...


CU Gremlin.

edit: aufgeteilt von https://community.dieselschrauber.org/en/viewtopic.php?t=4590
gremlin


Hi,

Gremlin hat perfekt recht. Das IBM-Teil braucht 16,8 Volt, mit einem EINFACHEN Ladekabel ists also nicht getan.

Es gibt dennoch ein KFZ-Netzteil dafuer, das kam irgendwas ueber 200 Euro.


Jan

Moin,

schau mal bei www.reichelt.de rein. Da gibt´s Universal-Schaltnetzteile für Notebooks mit 70 Watt und 11-14Volt Eingang. Die Ausgangsspannung läßt sich zwischen 15 und 24 Volt einstellen. Das sollte ideal dafür sein und kostet nur 34,70 EUR.

Grüße

Eike

Hi,

"@Eike: That should also work, and you're right."

"@Gremlin: I'll try testing the grounding next, maybe that will be enough. It's not completely unusable, it just disconnects very quickly when the engine is running."

Best regards,

Jan.

Try putting an isolation transformer between the laptop and the inverter.
I think it will work then, but I'm not sure. Maybe you could try it and post the result.


Regards,
Bubu.

eike wrote:

Take a look at www.reichelt.de. They have universal switching power supplies for notebooks with 70 watts and an 11-14 volt input. The output voltage can be adjusted between 15 and 24 volts. This should be ideal for that purpose and costs only 34.70 EUR.

That's exactly the type of part I use for my IBM laptop, and it works perfectly. I paid 25 euros for it at the online retailer E...Y.

I also have the one from reichelt.de, but I didn't buy it on eBay (I should have checked!). It works perfectly fine on my very old and basic laptop. You can buy it without having to do any modifications or DIY.

Hi,

Do these devices have galvanic isolation between the primary and secondary sides? My car adapter doesn't have optocouplers, so this could be a problem.

Best regards,

Jan.

Hi,

Do these things have galvanic isolation between the primary and secondary sides?
Not necessarily. A small voltage increase can be achieved using choke coils.

'By the way, I can't find a power supply like the one mentioned above on the Reichelt website... either I'm too stupid to search, or this wonderfully certified company doesn't want to sell anything to me.'
I'm already over them. They're riding on their high horse and packaging semiconductors as bulk material in plastic bags!

CU Gremlin.

Jan6K wrote:

...do these things have galvanic isolation between the primary and secondary sides?

Mine does, because I would consider 4.9 MΩ to be a level of galvanic isolation.
This device still draws 2.9 amps even at 24 volts!

http://www.vanson.com.hk/details/vansonnel2024a.html

http://www.vanson.com.hk/cgi-bin/ngen_details.pl?UCODE=238971&LANG=&LOOP=PROD

Hi Bertil,

"That sounds very good! I need to check if I should buy something like this instead of trying to use mass cables, because the prices sound absolutely reasonable, and it would save me from having to carry around another device."

Best regards,

Jan.

Hi Jan,

The fluctuating voltage isn't a problem as long as you stay within certain limits, because there's another (step-down) switching regulator located at the power input of the laptop. It can certainly handle up to 19 volts; how low you can go would need to be tested. You could also use one more cell and stabilize it at 16.8 volts with a low-dropout regulator, but I don't think that's necessary.

Since you're not providing galvanic isolation, that feature will only help with charging the battery.

'Using an isolation transformer is not a good idea because the (cheap) inverter essentially produces a square wave voltage, and transformers react to this due to the extremely high harmonic content, generating a lot of heat. Furthermore, the transformer is very inductive when idle, which can damage the inverter. This doesn't apply to pure sine wave inverters, but they also don't have the interference problem.'

Hi,

and that's exactly why it's very ineffective. Because it's usually full after about an hour, and then it only lasts for 5 minutes .

Therefore, I will first test the variants that use galvanic isolation.

Best regards,

Jan.