openinverter forum

FlexyZ wrote: ↑Tue Dec 16, 2025 11:27 pm When are you releasing the CAPE board?

Nothing to stop me really. Could basically put it up on the shop now with a couple of weeks lead time

I understand now that the voltage has to be the same supply side before the car will close the contactors. So what high voltage supply device are you using to get that step done?

Thank you and sorry for the stupid questions
Felix

Look on ebay for "5V400V"

Should look like this:

Thank you - so in your setup, how do you control the supply to output the correct voltage?

I don't
I connected 10uF to its output so the ramp from 0-400 takes 6s. I simulate this cap curve in pyplc and rely on the fact that 30ms<<6s so the precharge will complete when voltage suits.

Alternatively you can supply PWM directly to the converters FET and control output voltage with pwm frequency

got it and thanks again

Johannes,

The MQTT commands you run on the video are actually sent to the beagle board and from there to the inverter?

So beagle board is controlling duty cycle on CCS and contactors?

is the beagle board source code available?

Thanks again
Felix

Yes, to the inverter via https://github.com/tjhowse/modbus4mqtt

It is configured via sungrow-modbus.yaml

https://github.com/jsphuebner/esp-egyco ... ry-control

beagleboard controls CP PWM and the changeover relay between stationary and car battery. Contactors in the car are run by Foccci

I'm wondering if I can use this to use my new Cupra Tavascan as a Home battery together with my Sungrow SH10RT hybrid inverter?

Not quite. pyPlc talks the DIN protocol which is meant only for charging. Quite a few cars will also allow discharging during a charge session but the MEB cars do not allow this.
To make it possible we'd have to marry pyPlc to ISO 15118-20. With that MEB cars allow 10 MWh of discharging. So obviously not a full replacement for a home battery but an addition.

johu wrote: ↑Sat Dec 27, 2025 9:41 am Not quite. pyPlc talks the DIN protocol which is meant only for charging. Quite a few cars will also allow discharging during a charge session but the MEB cars do not allow this.
To make it possible we'd have to marry pyPlc to ISO 15118-20. With that MEB cars allow 10 MWh of discharging. So obviously not a full replacement for a home battery but an addition.

Thanks for your answer - is your plan to implement ISO 15118-20 in the future? Would be great. I'm getting the car in about 8-10 months from now, would be very nice If I can implement your solution then to use the 10MWh allowed discharge as an addition to my Home battery. Currently I have the Sungrow SH10RT + 9.6KWh battery.

If I can do anything to help let me know, I am no C++ expert, but I have lots of experience with Python, Linux, and e.g. Home Assistant which I use for e.g. intelligent energy usage (PV + dynamic energy tarrif)

johu wrote: ↑Wed Nov 19, 2025 10:15 am I set up a wiki page https://openinverter.org/wiki/FoccciCape

I've also added the precharge supply back in. I connected a 10uF 400V elcap and a 1M resistor to the output. This gives it a pretty deterministic voltage ramp which I think is also slow enough (0-400V in 6s) so that the vehicle will just report precharge completed.

Will start selling it on the shop soon. Hows interest?

I'll be intersted as well, if I could use it together with my current installation. Currently I have a pv Inverter from SMA STP-100-3SE-40 and a connected BYD HVM Battery. The SMA inverter should be similar to your Sungrow. My car ist meanwhile a BMW i3s. The management of my smarthome is iobroker with javascripts that manage tibber, the Sma inverter and many other things. So the main thing I'm looking for is a solution to get the energy out of the car as well. What else beneath of your cape ist necessary for my environment?

The list of tested cars is here: https://openinverter.org/wiki/Bidirectional_Charging
For all other questions I think it's best to watch the latest video

johu wrote: ↑Thu Jan 08, 2026 1:02 pm The list of tested cars is here: https://openinverter.org/wiki/Bidirectional_Charging

so no one tried it with an BMW i3 until now, whether it's possible or not, then maybe I should trie it. maybe the older i3 is different to the ix platform from BMW. I think BMW did it already together with a Kostal inverter in a pilot project. And BiDI charging should have worked there - don't- now how they did the communication but it worked.

according to this description, the i3 has been modified for this project: https://www.ffe.de/veroeffentlichungen/ ... bmw-i3-um/

that said, if you live somewhat close to Linz in Austria you are welcome to test your i3 with my DIY DC wallbox

@lewurm did you create the charger based on Johannes work or your self?

not this cape in particular, but it would have made it much much easier for more details read through the other thread: https://openinverter.org/forum/viewtopic.php?t=3551

lewurm wrote: ↑Thu Jan 08, 2026 9:49 pm according to this description, the i3 has been modified for this project: https://www.ffe.de/veroeffentlichungen/ ... bmw-i3-um/

that said, if you live somewhat close to Linz in Austria you are welcome to test your i3 with my DIY DC wallbox

was this or something similar the modification in the i3 so that it worked?

https://mandrill-engineering.de/wp-cont ... l-BiDi.pdf

Slide 8 - Mandrill charging controller

Yes, I m not so far away from Linz, and I probably will come to test at your Wallbox in spring when the weather becomes better.

johu wrote: ↑Wed Nov 26, 2025 6:53 pm What would be the "minimum viable product"?
- Just the cape
- Cape + preprogrammed BeagleBone

maybe both versions or both parts separate. I will try it at first by myself with just the cape to learn, and if I fail to get it running I would take a programmed BeagleBone as well or just the ssd with all the configuration. Which software(Version) are you using on the BeagleBone?

I'm doing the first steps now, I've never used beaglebone before, so a lot to learn. Just some beginners-experiences:
- I'm using the BeagleBone Black (BBB) because I thought that desktop mode with HDMI helps me. But it does not, see below.
- microSD card is not required for normal operation. The BBB has internal eMMC. Booting from microSD requires holding a button during power-on, this is impractical in daily life.
- Booting the image am335x-debian-11.8-xfce-armhf-2023-10-07-4gb.img.xz from microSD to graphical desktop took ~3 minutes, this is disappointing.
- microSD card IS required to update the OS on the eMMC.
- My BBB was delivered with a quite old version, cat /etc/debian_version says 7.9. This has still python 2.7, and got lot's of errors when trying to install python packages.
- trying to install a recent image incl graphical desktop on the eMMC (https://files.beagle.cc/file/beagleboar ... 4gb.img.xz) leads to "disk 99% full". So this is no option.
- Trying to go with a small image now: https://www.beagleboard.org/distros/am3 ... ot-flasher. This reports the same version as johu showed above:
debian@BeagleBone:~/myprogs/pyPLC$ uname -r
5.10.168-ti-r71
- Beginners lessons for the BBB helped me, e.g.

Got the new boards in yesterday And immediately spotted a problem, dead short from 3v3 to GND. Turns out down to my ego: DRC warned me about it and I ignored it. As celeron says, DRC always wins.
Nothing a Dremel can't fix.

I tried the new PWM generator and it isn't really much better: When loaded with 2k7 it drops very close to 8V instead of 9V.

All else remained unchanged so should just work.
Tried to add it to the shop but it doesn't let me add a picture anymore

I finally fixed the shop and now you can order the board: https://openinverter.org/shop/index.php ... duct_id=81

Depending on perception I will add more options later, like the preloaded BeagleBone and more connectors.

Thanks to Johannes I got a FoccciCape on my desk. Added a display via CAN. Dry-run with using Foccci as car works fine. Very excited to connect it to my Ioniq... Coming soon...

Ioniq is happy, but only for two seconds. (Cannot add pictures, is the forum disk full?)
Edit: Now the pictures work, see below

Random file. Works. Disk is only 14% full