Victron VE.Direct to USB cables vs Generic PL2303 USB-Serial adapter

The Victron cables are crazy expensive, can I use a generic PL2303 TTL USB-Serial adapter?
I'm trying to get a VenusOS Raspi up and running and not spend $100+ on VE.Direct to USB cables.

Will it work?
Are there different types of the PL2303 chipset that I should avoid?
I'm assuming I need to use 5v not 3.3v
Is this pinout correct for all VE.Direct ports? The RX and TX should be flipped?

Thank you

Might have found a solution out of Italy.
Isolated 4 port USB to serial. They also sell RX/TX swapped 2.0 JST PH cables.


Hit me up a month from now I'll let you know if it worked

I used these, and moved the pins around in the plug.

The physical interface is balanced pair similar to RS485 physical interface.

To convert to RS232 you can use an RS232 to RS485 converter. It is basically just a MAX485 eight pin I.C. to convert serial RS232 to RS485.

You can also get a USB to RS485 converter. On a computer or Raspberry Pi the USB connection shows up as a comm port assignment just like a RS232 serial port would. These have a USB to RS232 chip followed by MAX485 RS232 to RS485 chip.

The MAX485 chip should have 5v supply but the serial interface is compatible and can be connected to either a 3.3v or 5v serial logic voltage level.

These modules are pretty low cost.

Both RS485 to serial and RS485 to USB are available on Amazon.

For the balanced RS485 pair, only the first and last devices should have 120 ohm terminations to the balanced transmission line. Some modules you buy have no terminations, some have it included and connected, some have the termination resistor with a jumper you can put it in for first or last device or remove jumper for middle of line run connections. You can check with an ohm meter to see if it reads near 100 ohms.


Twisted wire pair has Zo of about 100 ohms. You can use CAT5 or CAT6 ethernet cable which has four individual twisted pairs.

I've read a few posts on the Victron forums where lack of isolation and ground loops were causing massive problems.
I'm reasonably sure the Duppa products I linked are a quality product that doesn't have these issues. The hardware looks really good.
The price is about as much as a single genuine USB to VE.Direct cable so I think I'll bite the bullet and give it a whirl

There is three levels of protection. Cheapest is no protection, second level is ESD and resettable fuse interface, third level has full galvanic isolation.

You can buy the converters with galvanic isolation. They have either optical (LED) or magnetic coupling that keeps the MAX485 chip isolated from the serial data lines.

The 5v supply for the MAX485 chip has to be an isolated supply. Some modules have an isolated 5v to 5v DC to DC converter to provide this isolated supply. (black block in upper left hand corner of picture, about $20 for module)

I have 4 of the AdaFruit cables in use today. No issues for 3 or so years.

totalconfusion said:

Might have found a solution out of Italy.
Isolated 4 port USB to serial. They also sell RX/TX swapped 2.0 JST PH cables.

Isolated 4 port USB to TTL UART FTDI – DuPPa

www.duppa.net

VE.Direct JST cable – DuPPa

www.duppa.net

Hit me up a month from now I'll let you know if it worked

Click to expand...

I bought those cables and isolated adapter.... And I bought a Raspberry Pi to run the software on.

AMAZING is all I have to say. Just burn the SD card for the Pi and then plug everything in. Connect to the pi from the Victron phone app and associate it to your account and IT JUST WORKS.