Controlling Webasto Live-Wallbox, start/stop charging

Hi everyone,

I am doing some research on how to control my Webasto Live-Wallbox through Modbus as I want to charge my EV with regard to PV-production and overall consumption of my home.

With the register addresses for TQ-DM100 I am able to receive all necessary information and can control the maximum ampere for the current session at 5004 “charge current in A”. What I do not see is an address to switch charging on and off when the EV is connected.

Sadly Webasto Support is not able to assist me on that case.

Another google search led me to the nymea plugin for Webasto Wallbox by @bernhard.trinnes - after some closer looks at the source code on github I wonder if you are able to start and stop charging and how you do it.

I understand that you work with the register addresses 5000 and 5001 as writable addresses. The documentation for the TQ-DM100 implementation by Webasto states that both addresses “charge power in W”.

Maybe you see a chance to assist me on that case even with my challence not being related to your project.

Thank you very much.

Best

Stefan

Hi,

I double-checked the modbus register map, and indeed there is no register to disable charging.
You’ve found a bug in the plug-in, thanks for that! Usually the min. current is 6A on wallbox chargers, maybe this wallbox disables the charging if the set charging current is 0A, I doubt it but worth a try. Otherwise, I don’t see any possibility to disable charging on this model.

Bernhard

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The “Ebee” modbus register map has both writeable registers, “max charging current” and "disable/enable chargin

Hi Bernhard,

first of all thank you very much for taking some time on that issue. I really appreciate!

Is there any chance you could provide me with the “Ebee” modbus register map you had been looking at? Or confirm I got mine correctly with:

Holding 124 Charge Point
availability
R/W 1 Get/Set
available/unavailable
UINT
16
Holding 131 Safe Current (Amps.) R/W 1 Max. charge current
under communication failure
UINT 16 A
Holding 132 Comm. Timeout
(seconds)
R/W 1 Communication timeout UINT
16
s
Holding 613 DLM Operator EVSE Sub-
distribution Limit
L1
R/W 1 Operator current limit for DLM available for distribution to EVs UINT 16 A
Holding 614 DLM Operator EVSE Sub-
distribution Limit
L2
R/W 1 Operator current limit for DLM available for distribution to EVs UINT 16 A
Holding 615 DLM Operator EVSE Sub-
distribution Limit
L3
R/W 1 Operator current limit for DLM available for distribution to EVs UINT 16 A
Holding 1000 Hems Current
Limit (A)
R/W 1 Current limit of the
HEMS module in Amps
UINT
16
A

I understand that 1000 is equivalent to “max charging current”, right? Is 124 “enable/disable” or is there a different one not in my list?

Wish you a great day.

As the Ebee register does not provide the same set of information as TQ-DM100 I followed the idea of setting max current to 0 - consequently it stoped the car from charging - with error warning - but does not lead to setting the CP status to disabled - which is at least partly true, because it will resume the very moment the current is set to 6 or higher.

I will try a bit and maybe I can either work with the limitations of either the register sets or find another solution.

Anyways; thanks again for the assistance.