Questions Victron ESS communication cables

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question

rasti asked Mar 4, '22

Questions Victron ESS communication cables

Hello,

I am planning a Victron ESS with the following components

- Multiplus 2 48V / 5000 (only one in a 3-phase-system)

- Cerbo

- Touch 50

- MPPT RS 450/200 (all 4 PV inputs connected to solar modules)

- EM24

- home made 23kWh LiFePo4 battery with SEPLOS BMS

- grid parallel topology (only one phase connected to L1)

I have the following questions:

1) I EM24 ethernet or RS485 version ?

In my special case I have a long distance (20m) between the EM24 and the Cerbo GX.
Which one (ethernet or rs485) do I need ? Are both OK ? If I use the RS485 version, I understand it is connected to the cerbo with a USB/RS485 converter ? Is this correct ? And is this USB/RS485 converter included when I order the EM24 ?

2) Which cables do I need for interconnections, I am confused about VE BUS, VE CAN , VE Direct ?

So which cable do I need

- between Cerbo GX and Multiplus2

- between Cerbo GX and MPPT RS 450/200

- between Cerbo GX and Touch 50

???

Thanks in advance for your help

Regards

Ralf

ESS victron

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Modifications Space

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Answer 1 · 2022-03-04T09:33:56Z

Alexandra answered · Mar 04, 2022 at 09:33 AM

@rasti

The product pages have everything you need to know. Manuals and pictures at the bottom of the pages for each product. Each product has a technical specifications page like the mppt rs one.

Victron inverter to Cerbo - VE Bus. All connections can be seen in the Cerbo manual.

RS Mppt - VE Can if you want to daisy chain a few. VE Direct of you want to, really both options are there.

Cerbo and touch 50 come with everything you need to power up and connect them together so nothing there.

On the EM24 since there are two options that is up to you. And what is available. And you would need to buy the dat comms cables or what is needed for that.

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Answer 2 · 2022-03-04T09:45:59Z

rasti answered · Mar 04, 2022 at 09:45 AM

Thank you Alexandra.

Am I right that both VE Bus and VE Can are just normal LAN / Patch cables ?

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markus ♦♦ commented · Mar 04, 2022 at 09:57 AM

Yes - UTP = unshielded(!) twisted pair

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Answer 3 · 2022-03-04T11:07:31Z

rasti answered · Mar 04, 2022 at 11:07 AM

Hallo,

I have a (maybe stupid) question regarding the ethernet version of EM24.

I haven't seen any picture/foto of the EM24 ethernet port.

On this one https://www.ebay.de/itm/143979556259 for example, I only can see RS485 inputs.

Same thing for any other vendor I found on the internet.

Is the device on this picture really the ethernet version ?

So where is the ethernet port, anybody has a picture for me ?

Regards

Ralf

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markus ♦♦ commented · Mar 04, 2022 at 11:58 AM

This is how the EM24 ethernet looks like:

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67de3db8-ded5-4f24-a9f3-cdc58a385a3d.jpeg (3.4 MiB)

Answer 4 · 2022-03-04T13:29:42Z

rasti answered · Mar 04, 2022 at 01:29 PM

OK that makes sense. Thank you ! So in all the pictures where they are selling the em24 Ethernet they show a the rs485 version....

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Answer 5 · 2022-03-04T15:28:41Z

rasti answered · Mar 04, 2022 at 03:28 PM

One more thought on the Ethernet version of the EM24.

In contrast to the RS485 version there's no direct connection between Cerbo and EM24.Cerbo and EM24 both attach to the network, each of them gets an IP and then they can communicate.

IS THAT CORRECT ?

In my home I have a private LAN/WLAN for home automation and stuff like that and I have a guest LAN/WLAN which only connects to the internet outside. Of course I could connect both Cerbo and EM24 to my private home automation LAN/WLAN but maybe it is a good idea to add a tiny small router just for the victron components to make it completely independant from the rest.

Any thought on this, does this make sense ?

Regards

Ralf

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markus ♦♦ commented · Mar 04, 2022 at 03:49 PM

Your thoughts are good.

Of course it would be possible, to make a direct connection from the Cerbo to the EM24 eth. too. (LAN with only 2 devices)

Your thoughts are the reason why I like the RS485 version more than the ethernet version. If the LAN goes bad for some reason, the communication to the EM24 is lost.

It is therefore a good idea, to use a separate router (or VLAN) to create a separate LAN for the Victron components.

BR

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Answer 6 · 2022-03-04T16:52:44Z

rasti answered · Mar 04, 2022 at 04:52 PM

Hi Markus,

when you say ,".... it would be possible, to make a direct connection from the Cerbo to the EM24 eth. too. (LAN with only 2 devices)...". how would the connection look like ? Could I also use a simple switch (not router),one input connected to Cerbo, one input to EM24 and one input to the internet,. Does that make sense ? Could the EM24 and Cerbo communicate in case if internet input of this switch is dead ?

Or do you mean that one ethernet cable directly connects the LAN ports of the cerbo and the EM24 ? The connection of the cerbo to the internet only can be WIFI in this case because there is no second lan port.

Regards

Ralf

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markus ♦♦ commented · Mar 04, 2022 at 05:29 PM

„Or do you mean that one ethernet cable directly connects the LAN ports of the cerbo and the EM24 ? The connection of the cerbo to the internet only can be WIFI in this case because there is no second lan port.“

This is what I mean.

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rasti markus ♦♦ commented · Mar 05, 2022 at 12:16 AM

Thank you Markus,

OK I understand that.

But sorry for asking again the same question : Wouldn't a simple switch (instead of a router with new subnet etc) also solve the problem ?

In the sketch shown, Cerbo and EM24 are connected to a switch, and the switch is connected to the router which in turn is connected to the Internet. If Cerbo and EM24 have static IPs, then the communication between Cerbo and EM24 should also work if the connection to the router (orange cable) is interrupted ? Or maybe I understood something wrong ?

Regards

Ralf

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em24-cerbo-switch.jpg (62.0 KiB)

markus ♦♦ rasti commented · Mar 05, 2022 at 08:26 AM

Of course it will work as well like you draw it.

We were talking about possibilities for a direct LAN connection between the meter and the cerbo for stability reasons.

If you have a direct connection, there is no chance for IP address conflicts or any other disturbances by other clients in that LAN.

…but it is not a must to create a separate LAN, of course.

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rasti markus ♦♦ commented · Mar 05, 2022 at 09:26 AM

Hi Markus,

thanks for confirming. Regarding the above setup with a switch: Of course I am in trouble if e.g. another client claims the same IP as the EM24. I understood that. But adding that switch would at least add a small additional level of security,because I could completely disconnect or reboot the router anytime without interrupting the cerbo <=> EM24 communication.

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markus ♦♦ rasti commented · Mar 05, 2022 at 11:16 AM

"I could completely disconnect or reboot the router anytime without interrupting the cerbo <=> EM24 communication"

Yes - this will be true.

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