openinverter forum

I currently have some SDU boards on the bench that I marked as "repair". They are the latest with ESP32, i.e. V7 or V8, respectively.

I found the wifi module could be programmed but otherwise wasn't working. It didn't even present the "inverter" SSID.

Now on one SDU board I found the boot strap capacitor of the 5V supply (C52) was dodgy and lead to an unstable 5V supply.

But that wasn't the only culprit. The wifi module is decoupled from the 3V3 network with a 10uH 0603 inductor (L3). And that is only rated 3 mA! Slipped through when checking the BOM. So there is a varying voltage between 3.2V and 3.3V and I suppose it dips even lower, inhibiting startup.

I've only shipped boards with working wifi, maybe those had the tolerances in my favour.

So if you discover wifi connectivity is very unstable or not working at all, swap that inductor for one that's rated more like 200mA or just short it out completely. I'm doing the former for all boards now and will correct the BOM for the next run.

EDIT: I think this one is a better fit https://jlcpcb.com/partdetail/375368-CM ... MT/C394952 . Just 4.7 uH but I guess that's the best you find in this small form factor.

Thanks for this.

I see in the V8 BOM the same part is used for L1 and L3. Should both be changed to use C394952 or just L3?

I'm happy to make the change and send a PR.

Just L3

Those were referenced for the Gen. 3 Leaf adapters and slipped through there as well. Fixing it now in V0.0.3 and will update info in the proper places.

Hi, my name is Frederik and I am new to this forum. I recently purchased a SDU logic board and am unable to access the wifi. I have already shorted L3, but no succes.
The board shows one constant LED and one blinking.
What can I do next?
Thank for your help! Best regards, Frederik

Does the wifi name "inverter" show up at all? If so can you connect? Tell us which step exactly fails.

No, it does not show. I tried several devices. I only connected 13 and 19.

Ok. Can you measure 3.3V on the wifi side of L3?

Looks like the voltage fluctuates between 2.8 and 3.3 V. But I will try to do an other measurement later today.

Ok, that sort of swing would cause it to not work. Can you check the same for the other side of the 3V3 rail and also for the 5V rai?

Now I measure 3.0V on the 3.3 rail and 4.0V on the 5V..

And your 12V is stable and provides sufficient current? Can you post a picture of the power supply section - maybe something came off?

Read here also https://openinverter.org/wiki/Electronics_Basics

Thanks for your help. Currently busy with other things, but will follow up soon.

Hi, I removed the board from the inverter and reconnected it to the 12v power supply. Now I measure a constant 3.3V near the eps32, for example on the right side of R59. Unfortunately it still does not appear in the wifi list.

Ok, I guess something is not well then. I'll send you a new one, please return the faulty one. Unless you want to try and re-program the ESP32. It needs the STM32 to be held in reset and then this: viewtopic.php?p=61098&hilit=python+platformio#p61098 with the files found here https://github.com/jsphuebner/esp32-web-interface and also the command

Ok, please send a new one. Thank you! I will return the one I have now.

This post is interesting and may explain the problem with my board, which worked fine 4 years ago but now will not connect reliably to wifi. It has an L2 inductor but not an L3 - is this a typo ?

No, this is just relevant for the newer boards with wifi soldered to it.

My board is V6 but does not have L2, just L3. The supply to the wifi module is measures at 3.4V, However I always have issues connecting on wifi (intermittent) and when I connect I can upload parameters OK but cannot download spot values - Just get a blank page. Does anybody have any ideas as to what the problem might be?

Can you supply a picture of your board?

image1.jpeg image1.jpeg

Yep, typo in my opening post, should say V7, V8. This thread doesn't apply to your board then. Just make sure the 3.3V rail is dead stable. Measure between some GND and the upper rightmost pin of the wifi module socket

Is the design intent for the V8 boards for the user (me) to source my own ESP32 chip and install it? Or were these part of the poor connectivity issues when the inverter is closed up, and hence the move away from them?

The design intent of V7 was to replace the esp8266 plug-in module with the soldered esp32 module. Turns out either way the connectivity is poor. So the boards I sell now do not have any wifi module onboard but you can choose to buy a CAN connected wifi module that can live pretty much anywhere in your car.
I've lowered the prices for the logic boards so the separate module doesn't add as much to the total cost.