openinverter forum

What was the fix?

i have made a self build isa shunt based on a ESP32 because i find them to expensive, and on there a also put a DAC for this purpose. i calibrated the values but the adc misses sometimes a reading and that is what you see. it's a external adc wit opto insulation so i guess these is sometimes a timing issue or something, for now a masked the " wrong" values and it is working for now. later i will fix this the right way off course.
if anybody is interested a can share my design of this sensor i've made, but for now there are some bugs to be fixed before i want to make is public. the design is so you can order them yourself at JLCPCB.

any idea if the relays should close during the welding test?

nathaniel wrote: ↑Wed May 03, 2023 8:23 pm During the weld test I also don't hear them closing, assuming this would be the case. Can anybody confirm that?

You should hear them click. Are you sure it's carried out? How is the 0x272 message behaving?

nathaniel wrote: ↑Wed May 03, 2023 3:19 pm one more question, in anticipation of the next step, my current sensor reads a positive value when I use current from the battery when driving, and a negative current when I charge. so when i go to charge it will report negative current to the lim, is this correct or not?

Positive amperage is charging.

I think you connected the relays wrong. One is on pin 1+3, the other on 2+4!
Not 1+2 and 3+4

christoph wrote: ↑Thu May 04, 2023 8:58 am You should hear them click. Are you sure it's carried out? How is the 0x272 message behaving?

The message goes to zero, during the test I can see it working in the log and is passed successfully. It was failing first so I swapped the priory on the relays, they have a diode in them. Guess it has something to do with it. They are connected om pin 1 and 3 Abd the other one on 2 and 4. But now I know that the problem is in the relay part so I know what to fix. I'm happy that the charger was working to give me power! For only the second try not bad I think

I haven't had time to test the relay setup but in the meantime I have an other question also regarding the AC and DC charging with the LIM. I use the LIM now also for AC charging so if I plug the cable in the LIM sends the data to to vcu and the vcu commands power and the LIM closes the plug lock and the AC charging starts. But I want to be able to stop the charging from the car side, and as far as I can find its only possible to do it via the web UI. I've tried to map a custom van message to the Chgctrl but it didn't like that. Am I missing something or is it now not possible other then via the web UI to stop the charging from the car side?
Stopping the charge via the evse side is working but my granny cable can't do that, do I have to go in the web UI to stop the charge for now

nathaniel wrote: ↑Wed May 03, 2023 8:40 pm i have made a self build isa shunt based on a ESP32 because i find them to expensive, and on there a also put a DAC for this purpose...

A custom high voltage and current sensor board sounds very interesting.

Just wanted to share this with you guys, I got ccs working thanks of your help! I installed small relays that switches the big ones and that did the trick. Strange thing is that I use 30 ohm resistors because that was the only thing I had. But the LIM is accepting that it seems. Swapped the current sensor values but my sensor reads about 10% higher then the charger but that seems also not a problem.

nathaniel wrote: ↑Wed May 03, 2023 8:40 pm i have made a self build isa shunt based on a ESP32 ...

Please share your design. Thanks in advance.

In the next couple of days I will make a project on the forum for that. The design exist out of a couple of different boards and I want to share also what my design distortions where to give a bit of understanding how it came to be. I post a link here when I'm finished with that

nathaniel wrote: ↑Wed May 03, 2023 8:40 pm i have made a self build isa shunt based on a ESP32 because i find them to expensive, and on there a also put a DAC for this purpose. i calibrated the values but the adc misses sometimes a reading and that is what you see. it's a external adc wit opto insulation so i guess these is sometimes a timing issue or something, for now a masked the " wrong" values and it is working for now. later i will fix this the right way off course.
if anybody is interested a can share my design of this sensor i've made, but for now there are some bugs to be fixed before i want to make is public. the design is so you can order them yourself at JLCPCB.

I was worried, until you mentioned using an external ADC, as the ESP's onboard ADC is notorious for issues (non-linearity, requires manual calibration for the ±6% out-of-the-box variance, and foreshortened actual measurement range, etc.). It's fine for some hobbiest-level tinkering but rubbish for ADC where the digital representation of the signal needs to be close to reality.

We are coming more and more off-topic, so only short: A simple high-voltage measurement is shown here: https://github.com/uhi22/pyPLC/blob/mas ... d#dieterhv Could be extended to also measure current, just by using a shunt and amplifier.

The IVT-S current shunt w/three HV inputs and CAN output is fairly expensive (though also very reliable and a quite nice piece of hardware), and I find that discussion of alternatives to it are on-topic for this thread, as some kind of current sensing (and translation to CAN) is required by the i3 LIM and ZV combination, unless one modifies the supplied ZV software.

Could discussion of alternative current sensing devices be put in a separate, dedicated thread? Sure, and maybe if this becomes a detailed discussion it should then be moved to such a thread, but in the last 44 pages of development we have gone off on several side tangents . . . and always return to whatever is the hot topic today.

I can confirm that every CCS try until now was working perfectly, even the Tesla superchargers! And also fastnet, big one here in the Netherlands
Super happy!

asavage wrote: ↑Mon May 08, 2023 1:48 am The IVT-S current shunt w/three HV inputs and CAN output is fairly expensive (though also very reliable and a quite nice piece of hardware), and I find that discussion of alternatives to it are on-topic for this thread, as some kind of current sensing (and translation to CAN) is required by the i3 LIM and ZV combination, unless one modifies the supplied ZV software.

Could discussion of alternative current sensing devices be put in a separate, dedicated thread? Sure, and maybe if this becomes a detailed discussion it should then be moved to such a thread, but in the last 44 pages of development we have gone off on several side tangents . . . and always return to whatever is the hot topic today.

I'm working on a OEM style current sensors incl. voltage sensing.
The idea is more affordable then the IVT-S.

I'm not using the LIM, But I have ordered a HDH-21 to mess about with for the DC Voltage monitoring.
12v powered, 4-20mA output, 0-400V input (Likely 0-500V).
https://www.aliexpress.com/item/1005003767797166.html

I reckon that with some adjustment of the Zero / Span pots, it'll be possible to mimic what the LIM is looking for.

Seems like it's an isolated design, but I'll be cracking mine open to investigate.

Would gladly accept a IVT-S replacement! buying one new was by far the most painful cost justification of the whole build.

I once ordered a similar unit. After opening it I decided to go another route and develop the Voltage Sense Board.
This is what it looked like:

Not quite a robust design!

I apologize if this has already been answered, but can any old i3 LIM module work for this? or must it either be programmed fresh or from a wrecked i3 that had CCS on it previously?

There's a chart of LIM part numbers known to work at the Wiki:
https://openinverter.org/wiki/BMW_I3_Fast_Charging_LIM_Module#LIM_versions.

A used unit from a wreck, etc., should "just work", provided it was from a vehicle that was provisioned for CCS; see note about this at the link above.

A new, un-coded LIM will not work; it must be configured first. There are at least two ways to do this, and they're outlined at the Wiki:
https://openinverter.org/wiki/BMW_I3_Fast_Charging_LIM_Module#Programming_a_new_LIM

I know I promised to share my current sensor design but I'm a bit delayed with the revision. The sensor can be more stable and I've make a new revision but I need to test it first before I want to share it. As soon as in happy with the result I share it for you guys.

But in topic, in the meantime I've been super charging a lot. One time I had a hard time to get it to charge, first hanging on state 5. But then I remembered that I didn't do the relay welding test. And after that it took a couple of tries and it keeps in hanging on state 2. After some trying it works again. No logs unfortunately.

Now on vcu 2.0 firmware and working. But the thing why the welding test is not performing is that the CP_DOOR always starts in error state. I have a switch on the charge cap and I need to open the cap for a couple of seconds, then de CP_DOOR goes to open sand then I can close it again and it reports close. And then I can toggle the start of the vcu and the welding test is dining it's thing. My lim is connected to constant 12 volt and when I "start"the car it gets the 12 volt for that.
But after every "start" the CP_DOOR is in error state.
Das anyone also have this "problem" or am I the only one?

nathaniel wrote: ↑Sun Jun 04, 2023 8:36 pm Now on vcu 2.0 firmware and working. But the thing why the welding test is not performing is that the CP_DOOR always starts in error state. I have a switch on the charge cap and I need to open the cap for a couple of seconds, then de CP_DOOR goes to open sand then I can close it again and it reports close. And then I can toggle the start of the vcu and the welding test is dining it's thing. My lim is connected to constant 12 volt and when I "start"the car it gets the 12 volt for that.
But after every "start" the CP_DOOR is in error state.
Das anyone also have this "problem" or am I the only one?

I have not had this issue but often need to do a weld test when the supply of the voltage sense board was off.
If I keep the LIM and the sense board on I don't need to do a weld test.

bitterandreal wrote: ↑Thu Jun 08, 2023 9:58 am I have not had this issue but often need to do a weld test when the supply of the voltage sense board was off.
If I keep the LIM and the sense board on I don't need to do a weld test.

ooh thank you, that is very interesting. my voltage sense board is going off when my car is off.
how is your door contact connected? or just always in "open" state? and when you need to performe the weld test you close the contact manualy?

muehlpower wrote: ↑Fri Mar 17, 2023 4:49 pm As already written, I use nothing but a Vector CAN card, 12V supply and E-Sys. I have the Fahrzeugauftrag (FA) as a file and do not need to read it from the key. Due to the direct connection with the Vector Card, I don't need a BCD as a gateway either.
I don't know how to sort the pictures, so I numbered them.
The pictures are in the wrong order, bottom to top is correct. The first shows the FA editor, with it I can edit and save the VIN and options. Then you can see how I establish the connection, read the code from the LIM and how I can change the code. As an example, I unfolded two folders.20230317_172253.jpg

I'm trying to charge with more than 125A which seems to be the internal limit. I hope to find a parameter which makes this mutable?
How have you been able to decode the NCD configuration in the FDL-Editor?
If I edit the NCD all folders inside "Funktionen" are only dots.
Which PSdZData package full or lite did you use?
Have you been using the BimmerUtility to map CAFD?