openinverter forum

Proton wrote: ↑Tue Jan 28, 2025 3:32 pm For now I cannot even help myself.

Please start by looking at CAN networks and how the Open Inverter mapping of data works on the CAN bus. I believe this is key to help you answer some of your questions.

The issue you face and I also is the level of understanding is low to begin with. I find only after I have read things 4 or 5 times, probably had someone like Tom or Jamie or someone else explain to me several times and also played with it, do I feel like I somewhat understand. The biggest issue is terminology for me at least. Familiarise yourself with the interface, read about the can mapping and reread everything and hopefully you will start to understand. Where you don't or there are gaps, simple questions on that specific subject, and then feeding that back into the wiki is the best way forward for yourself, and the community which is the most important aspect of this whole project.

Please don't take anything I wrote as a sleight and I'm assuming stuff about you from the few posts I've read.
Also, anything you write/ask/clarify on FOCCI integration will be greatly appreciated by myself.
Good luck!

Good luck!

Yes, there are many things to be better described. To improve the situation, my idea would be, that the guys which detect the lack, try to formulate short and clear questions (I guess there are a lot of them in the heads of the readers). And we can collect them in an FAQ, and the experts can provide short answers in the form "Yes. Because ...." or "Depending on .... there are the following options A ... B ... C...."
I'm happy to support with the answers. No question is a silly question. Every question helps us to bring the knowledge into words.

Let's start:
Q: Does Foccci help me for AC charging with a Tesla OBC?
A: No. The Tesla OBC wants exclusive access to the control lines of the charge port. It handles the communications with the AC charging station by its own. This communication means providing the CP Résistance and measuring the CP PWM duty cycle. Foccci can also do this, but there cannot be two instances which do the same things. There is the other case: DC charging. For this, the Tesla OBC is not involved. The BMS needs to send the limits to Foccci, and Foccci performs the communication with the charging station.

This leads to the question: could the Tesla OBC provide the CP duty cycle via CAN to Foccci, and Foccci make the state C switch via CAN and the OBC, so that we could remove the CP PWM things (including state B and state C resistors) from Foccci?

uhi22 wrote: ↑Tue Jan 28, 2025 6:42 pm This leads to the question: could the Tesla OBC provide the CP duty cycle via CAN to Foccci, and Foccci make the state C switch via CAN and the OBC, so that we could remove the CP PWM things (including state B and state C resistors) from Foccci?

Anything is possible if you modify the firmware for both devices, as I stated at the start of this thread.

Same with yes you can change a Tesla Charger with OI control board to be a "dumb charger" that responds over CAN. There you just need to make sure the timing is right with the AC charging Voltage application, AC and HV. This is all very possible and has been done by myself before in client projects.

The key here is that all this gets defined properly then implemented across all involved devices. Which becomes again a web of options.

For AC charging
A. Which device controls the HV application to the Tesla Charger
B. Which device sends the charge current limits to the Tesla Charger
C. Which device tells the Foccci to start charging

At this moment all of the above is done by a ZombieVerter for all of the above for charger that are Zombie supported via CAN using "stock logic". (so not using an OI board. If you then decide to start want other devices to do parts but not all things can get messy quickly.

@uhi

My question would be what else this board would need to start charging.
- Can I use it with my current setup: Openinverter BMS and the 11kW Tesla charger?
- Since the Tesla is AC input only, what do I need to do DC charging.

And some explanation on few different scenarios so I can at least have an Idea of what can be done with the Board.
A video would be the best.

I want to buy it because I need to be able to use chargers if I go far from home but I need to understand first if I can use it and how I can use it.

The fundamental difference between AC and DC charging:

When AC charging power conversion from AC to battery DC takes place in the car. The Tesla charger is such a device.
When DC charging power conversion from AC to battery DC takes place outside of the car, allowing much higher power because there are no space and weight limitations.

Both variants need to be informed by the BMS how much charge current is allowed.
The Foccci is a communication gateway between the cars BMS and the external charger.

A decent BMS must calculate this limit continuously based on cell voltage, temperature etc.

The OI BMS, Tesla charger and Foccci have a CAN bus. All can be freely configured to exchange the required data items (charge limit, soc, battery voltage)

The OI BMS comes with a fixed mapping of these items but allows a custom mapping in parallel.
The Tesla charger also comes with a fixed mapping (compatible with CHAdeMO) but also custom mapping may be added
The Focccis I ship out come with CHAdeMO mapping as well

So if I understand correctly, the Focci BMS will tell the external charger how many AMPs and the voltage it needs to send to my car.

Proton wrote: ↑Wed Jan 29, 2025 2:17 pm the Focci BMS will tell the external charger how many AMPs and the voltage it needs to send to my car.

For DC charging:

The BMS tells the FOCCCI max voltage and current for charging. The FOCCCI the negotiates with the DC Fast Charger (external charger) how much current it can provide based on the limits.

The FOCCCI listens to the BMS so the BMS always is in control of the MAX voltage and current.

I found this video.

Did it give you any info that is not on the wiki?

If so add it to the wiki.

tom91 wrote: ↑Fri Jan 24, 2025 12:56 pm Note that if you have an STM32 control board there also is a crap load of CAN ids on the bus because of having only one CAN, so it will be required to most likely be on its own CAN bus as it will conflict with other ids.
I have done this in a past project with the Tesla Charger, but a very very old board that was running my own firmware (I wrote the original firmware to control the Tesla Chargers).

Hi Tom, is there really only one CAN channel on stm32 versions of Tesla charger control boards? No external CAN?
I'm also still using this very old SAM3X based control board with 2 CAN channels and wonder if you would share your code version that you mention above where cp and pp are received over CAN?

m.art.y wrote: ↑Thu Jan 30, 2025 10:09 am I'm also still using this very old SAM3X based control board with 2 CAN channels and wonder if you would share your code version that you mention above where cp and pp are received over CAN?

No I wont share that code as it was coded for something I put togethor myself. I has no way of working with anything currently released, so its no use to you at all.

tom91 wrote: ↑Thu Jan 30, 2025 9:23 am Did it give you any info that is not on the wiki?

If so add it to the wiki.

OK I just realized that I can edit the Wiki and I added the link for the Youtube video. The auto translation in English is not that good but is usable
https://openinverter.org/wiki/Foccci

Proton wrote: ↑Thu Jan 30, 2025 6:47 pm OK I just realized that I can edit the Wiki and I added the link for the Youtube video. The auto translation in English is not that good but is usable
https://openinverter.org/wiki/Foccci

I've not viewed the video but given its an external source the information would be best typed up on the wiki if you can, that way it's not lost if the video is not accessible for any reason.

I would say that the creator of the Foccci is better suited to do that. I am still learning.

Proton wrote: ↑Thu Jan 30, 2025 6:47 pm the Youtube video. The auto translation in English is not that good but is usable

Even the german transcript is quite ugly, most likely because our German is not like a written book
The video is a quite "high level" overview on the one side, and has too much details about the communication, I'm not sure how much it helps for integrating Foccci in a car. Even if the task would be to explain such a car integration, this sounds impossible, because there are many options, especially in combination with AC charging.
I started an FAQ section in the wiki, please feel free to add more questions there.
https://openinverter.org/wiki/Foccci#Fr ... _Questions