Alfen EV Car charger modbus intergration

[evertide]

Hi,

Does anybody have some experience on connecting the Alfen single Pro to the Plant modbus for monitoring the usage.
The Alfen needs/usages this for loadbalancing to make sure grid fuses are not blown but more importantly give priority to the house energy consumption.

the setup is a 27kW battery, 12kW inverter and a home gateway.

the Alfen can read a modbus but I need the modbus id and registers

I found these below and tested on some bus id but did not get any values that make sense back.

| Function. | Register | Type | Scale
|--------------------------|----------------|-----------|
| Current L1 | 36001 | int16 | x0.1 A |
| Current L2 | 36002 | int16 | x0.1 A |
| Current L3 | 36003 | int16 | x0.1 A |
| Current N | 36004 | int16 | x0.1 A |
| Active Power L1 (W) | 36101 | signed32 | x1 W
| Active Power L2 (W) | 36103 | signed32 | x1 W
| Active Power L3 (W) | 36105 | signed32 | x1 W
| Plant Total Power | 36107 | signed32 | x1 W

Regards

[purcell-lab]

connecting the Alfen single Pro to the Plant modbus

As far as I'm aware the SigEnergy system isn't able to control a 3rd party chargepoint via ModBus.

There is a good thread on ModBus integration for Alfen to use directly in Home Assistant, which would be a good first step to get monitoring from your chargepoint.

https://community.home-assistant.io/t/alfen-eve-pro-ev-chargepoint-interface-via-tcp-modbus/346000

[evertide]

Hi,

Thanks for the thread, excellent one for my next steps “how not to drain the battery by my ev” or “automate when to automatily charge the car when I want to”.

But the question on the modbus was from Alfen to Sigenergy not controlling the Alfen from Sigenergy. Ideally the Alfen needs to know how much the house is using so it will not overload the total power of the plant/grid.

The old setup was it got the usage from the P1 (homewizard p1) but now its behind the gateway so p1 gives zero since the battery can deliver (till its empty)

regards

[purcell-lab]

Ideally the Alfen needs to know how much the house is using so it will not overload the total power of the plant/grid.

You probably want to do that at the Home Assistant level as it would have full visibility of the SigEnergy entities and the Alfen entities.

Creating a template sensor in Home Assistant would tell you the total power remaining that HA could then send this value to your Alfen.

So you would have the Alfen talking ModBus to Home Assistant and the SigEnergy talking ModBus (through this integration) to Home Assistant. Home Assistant could then compare the values and issue the power limited commands you are seeking.

I posted a similar automation to set the charging amps for my Tesla Vehicle, so in your case instead of setting charging_amps in Tesla, you would set charging amps in your Alfen:
https://community.home-assistant.io/t/optimizing-use-of-unused-solar-power-to-charge-a-tesla/340818/12

[Frederik-Verwaest]

Hi,

I also have a Sigenergy and an Alfen and a Homewizard P1 meter.

Initially I also used it with the HW P1 meter for loadbalancing but now I'm controlling it directly from Home Assistant.

Then you can do whatever you want. For example solar charging without draining the battery or if you have not much time to charge let it use battery as well.

I'm using https://github.com/ThaStealth/alfen_modbus (available in HACS) to monitor and control the wallbox.

Did not experiment with your approach to let the Alfen read modbus values directly from Sigenergy...

Another (hacky) approach would be to create a fake Homewizard P1 device (e.g on raspberry PI - it uses a simple JSON based API)

Frederik

[evertide]

Hi,

Interesting approach.
My initial thought was: would the Alfen be quick enough to throttle down when, e.g., an oven or another large consumer is started? It would solve both my challenges in one go: 1) balance the total power, and 2) control the EV charger — when and how fast it charges.

Can you elaborate a bit on your setup? I am very curious about your setup/automations and Alfen timeout settings.

How does the triangle Home Assistant — Sinenergy — Alfen charger work togehter?

Many thanks,
Evert

[Frederik-Verwaest]

Hi,

In short what I currently have (is a bit work in progress)

1. In the Alfen I have configured the loadbalancing to use an extrernal EMS, set a safe current of 6A and a current validity time of 300 seconds (as a safety measure, the Alfen will fall back to the safe current if no update was done over modbus during last 300 seconds). I have also enabled 1 and 3 phase charging.

2. In Home Assistant I have created a template sensor that sets the currently allowed power for the EV to use.
   For solar charging this is the sum of:

• GRID power (export: positive; import: negative)
• Battery Charging power (charging: positive; discharging: negative)
• current EV charging power

I have also added a min/max slider to speed up charging if needed.

The battery is then used either to handle short dips in solar power (cloud passing or some other device turned on) or to help to charge faster if that is needed - my goal is to have max self consumption of PV and zero grid usage.

3. Using Node RED I have 2 flows:

• One that uses the allowed power value above as input and updates the allowed charging current in the Alfen when a car is connected and is charging (after passing it through a low pass filter)

• One to start/stop and to switch between 1 and 3 phase charging depending on available power

The behavior is simular to the Alfen's own load balancings algorithm (e.g in reaction time to solar power changes).
Most of the time I don't use the automatic switching between 1 and 3 phases because I'm not sure the car likes that if done too often.

For grid charging mode in winter I will add a slider to set max grid import power of the whole house (for Capacity Tarif in Belgium) and plan to put the Sigenergy Battery automatically in standby when the car is connected and charging.

Frederik