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Excess PV charging with SMA energy meter and Heidelberg wallbox

Posted: Sun Jul 31, 2022 6:47 pm
by johu
I have finally gotten around to program my fathers wallbox (is it even called wallbox in real english?) to charge his 2 electric cars (e-Golf and Seres 3) as much as possible with excess PV power. The system consists of
- 8 kW PV system
- SMA inverters and especially energy meter
- Heidelberg 11 kW wallbox with RS485 modbus communication
- e-Golf (2-phase charging up to 7.2 kW and down to 2.5 kW)
- Seres 3 (3-phase charging up to 11 kW and down to 3.7 kW)

I've decided not to implement dynamic phase switching for now (I think the wallbox may support it) and also I never interrupt charging when too little energy is available. In doubt it just charges with minimum power from the grid.

To talk to the energy meter I use this software: https://www.unifox.at/software/sma-em-daemon/
To talk to the Heidelberg wallbox I use this: https://github.com/leuzoe/hdec

For controlling charge power I reused my zero export scripts from here: https://openinverter.org/forum/viewtopic.php?t=2322

Still needs some refactoring but will attach here anyway.

Re: Excess PV charging with SMA energy meter and Heidelberg wallbox

Posted: Mon Aug 01, 2022 4:21 pm
by johu

Re: Excess PV charging with SMA energy meter and Heidelberg wallbox

Posted: Mon Aug 01, 2022 7:48 pm
by arber333
I really like the fashion of the day 8-).

Re: Excess PV charging with SMA energy meter and Heidelberg wallbox

Posted: Sat Aug 06, 2022 6:07 pm
by johu
arber333 wrote: Mon Aug 01, 2022 7:48 pm I really like the fashion of the day 8-).
Yes it's still alive :) When was that? 2014 or so?

Now some chart from todays charging session. It doesn't get any better. I've set the controller to pull 100W from the grid. That way it maxes out the stationary battery inverter instead of allowing it to charge the stationary battery with priority. So car is always filled first.

Here's the result
PortalChartsAPI.png
39 kWh go directly from PV into the car, another 8.5 kWh come from the battery and just 1.6 kWh come from the grid including the end of charge when there wasn't enough solar power. Max charge power was 8.7 kW. Right now the battery is back to 34% which should be enough for the night