Hi, I have two Pylontech US2000B and a Voltronic VMIII 5k for about 6 years. Voltronic is on mode PYL and communicates perfectly with the master Pylon via RS485, with a home made cable, this one:

 

Now I have a new Pylontech US3000C battery module, whichi I must use as master, so connect Voltronic with it. I have read that I need a new cable for this battery, one like this:

 

So I have made one.

The results are:

• US3000C does not communicate with voltronic with any cable, neither old or new. I have tried with only US3000C module, without US2000 modules connected. I have tried changing cable ends, one end in Pylon and the other end in Voltronic, and upside down.
• US2000C communicates perfectly with old cable and with the new one! How is possible!?

 

So...  the only think I could do is... update the Voltronic firmware. Do you think this could be the problem??? or it has nothing to do?

My actual firmware is:

U1: 20.65
U2: 02.21
U3: 00.21

Do you think updating the Voltronic U2 firmware will allow communication?

Is there any posibility of connecting a US2000B and a US3000C using the US2000B (I updated its firmware recently to v3.4) as master ?

 

Thank you very much

 

 

 

Edited February 22, 20251 yr by TomasCrespo

On 2025/02/22 at 7:04 AM, TomasCrespo said:

Do you think updating the Voltronic U2 firmware will allow communication?

Yes, I seem to recall that being necessary. I'm not at my computer; from memory 02.87 or 02.90 is the latest. 

Thanks
@Coulomb

I have just upgraded remote panel to version 102.73 and now US3000C communicates perfectly with Voltronic VMIII in PLY mode, only with the second cable.

I haven't updated main firmware (it keeps 20.65). Should I do it?

I have always thought firmware update is a dangerous operation

Edited February 23, 20251 yr by TomasCrespo

On 2025/02/24 at 5:26 AM, TomasCrespo said:

I have just upgraded remote panel to version 102.73 and now US3000C communicates perfectly with Voltronic VMIII in PLY mode

Good to hear that. Although x02.73 is over 2.5 years old  at this point. The latest I know of is 02.89. But no need to update if this works for you.

On 2025/02/24 at 5:26 AM, TomasCrespo said:

I haven't updated main firmware (it keeps 20.65). Should I do it?

No, for the simple reason that there are no newer firmwares available. The latest I have is 20.59 from 2018.

On 2025/02/24 at 5:26 AM, TomasCrespo said:

I have always thought firmware update is a dangerous operation

Danger is a relative thing. Voltronic keep using very inexpensive opto couplers; they are so bad that they normally run them at only 2400 bps! For firmware updating, they are run at 4x that speed, which sometimes reveals a slow one, and it can get hairy restoring operation after a failed reflash.