openinverter forum

Hello,
I'm currently working on a conversion project and came across this shunt on eBay:
https://www.ebay.com/itm/335212904644?h ... R9zBhtOxYw
I've noticed some differences from the one used in the ZombieVerter videos on YouTube(it uses CAN1 yet others use CAN2). My question is, can it be compatible with the ZombieVerter VCU?

I have that same PN ISA shunt that I got from EVWest and had it talking to zombie without issue, reading current and voltage on a bench test setup. That is a great price compared to what I paid.

Thank you for sharing. I also came across a YouTube video that thoroughly explains the significance of ISA shunts. According to the video, ISA shunts with CAN2 lack "CAN termination on Board," necessitating the addition of a resistor for CAN termination. Conversely, those with CAN1 already possess "CAN termination on Board." For further details, you can watch the video here:

It's a good price, I almost bought from them as well. Either can terminated or not will work you just have to add a termination resistor if you get a non terminated version. There is a good video on YouTube by 'figleafproject' I think that shows how to setup the non terminated version. You've already posted it!

Hi,
I please need assistance with the readings I am getting with the ISA Shunt on the ZombieVerter running version 2.04A? It seems to initialize correctly and readings fluctuate with random readings even with udc connected to 12vdc or 0vdc.

udc -83886.06 V
udc2 486539.25 V
udc3 67108.84 V
deltaV 637534.18 V
INVudc 0 V
power 0 kW
idc -1325400.12 A

Can this be caused by the shunt setup? If so how do I connect to the VCU to change the ISA Shunt setup?

Thank you.

Looks like it did not initialize properly what can bus is it on? Use can1 to init

I have tried both CAN1 and CAN2 with the same results. I have also run the initializing procedure multiple times and I have the 120Ohm termination resistor connected on X2 of the ISA shunt.

EmilF wrote: ↑Mon Mar 04, 2024 4:25 pm I have tried both CAN1 and CAN2 with the same results. I have also run the initializing procedure multiple times and I have the 120Ohm termination resistor connected on X2 of the ISA shunt.

And the shunt is powered on when you int?

Do you have access to an ardunio due?

https://openinverter.org/wiki/Isabellenhütte_Heusler

I batch program shunts, so I use the due with the code in that wiki page.

Yes both powered on at the same time. I will have to get hold of an Arduino Due and CAN Shield. I have not really worked with the Arduino products before... Can i use any CP2515 CAN Bus module with the Due or does it need to be the CAN-BUS shield?

EmilF wrote: ↑Mon Mar 04, 2024 8:27 pm Yes both powered on at the same time. I will have to get hold of an Arduino Due and CAN Shield. I have not really worked with the Arduino products before... Can i use any CP2515 CAN Bus module with the Due or does it need to be the CAN-BUS shield?

in sort yes you can,

i made a little board with a MCP2515 chip. I use it for programing the shunts and as my GVRET(generalized vehicle reverse engineering tool) for savvy can. its very useful to have.

Hi, I managed to get hold of a Arduino Due and CAN-Bus board with MCP2515 chip. Which pins on the Arduino Due do you use for SCK, SI, SO & CS?

The SPI connections are on the connector marked "SPI", just look up Arduino Due pinout for actual pins.

If you intend to run Savvycan then you only need one or two CAN transceivers, either a MCP2551 or SN65HVD230.
CANRX - CAN0 RX, CANTX - CAN0 TX.
DAC2 - CAN1 RX, Pin 53 - CAN1 TX.

Hi, I managed to get the ISA shunt initialized and working. I modified my CAN BUS adapter and connected just the transceiver to the CANTX and CANRX port.
Thanks for the assistance.

I had the exact same issue, nonsense readings like above (not my actual numbers). Setting IsaInit to on and power cycling everything on the 12 volt rail didn't work. I think I fixed it by setting IsaInit to on in my Zombieverter, then powercycling only the Zombieverter (not the ISA shunt).

I think this worked because the Zombieverter and Arduino due library both command the ISA shunt to stop producing output before sending the initialization commands. I looked at the CAN traffic with a logic analyzer, my Zombie sent the stop command before the ISA shunt sent its first message. Then a few milliseconds later, the ISA shunt started sending voltage and current measurements, even though in theory it should have seen and respected the stop command. So my conclusion is that the Zombie tried to start configuring the ISA shunt before the ISA shunt had finished booting. My success power cycling only the Zombie seems to support my theory.

I haven't tried to replicate this method because my ISA shunt now works and I don't want to break it, so take my post with a grain of salt. But definitely worth a try before buying an Arduino due and CAN shield.

I just followed the instructions on Damien's GIT page and it all initialised OK.
Its also might worth noting that the ISA shunt and the BMW S-Box seem to spit our similar and conflicting messages that upset the Zombie so don't run them together on the same CAN bus. I only did so on my test rig but things weren't happy till I pulled the S-Box connected, then it all normalised...