# EMUS BMS CAN unit -- how to wire



## marc02228 (Jan 15, 2011)

I just wanted to connect my EMUS BMS.
I ordered four CAN units to communicate between the different batterie modules (due to EMI).
On the EMUS homepage is this explanation.

But my CAN unit look different.
It has 2 cables, one with 2 wires (black and red) and one with 3 wires (black, red, green), coming out of it and one connector. The connector has a 4 wire (black, red, green, white) cable attached. 

I attached a picture of my CAN unit (1st picture) and two pictures, which I got from Elektromotus, before ordering the BMS, a few month ago.

Does anyone know how I have to wire this?

Thanks!!


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## marc02228 (Jan 15, 2011)

Got an answer from Elektromotus(attached). 
Took the red wire for "DN" instead of the green wire, because my two wire cable has a black and a red wire. 

It doesn't work. Checked it a couple times...
Any ideas?


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## marc02228 (Jan 15, 2011)

*SOlved*

solved the problem with a software and firmwareupdate from Elektromotus.


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## Tomaj (Oct 3, 2011)

I have the same problem. Communication between PC and main unit is OK, but there is no communication between main unit and CAN module.

Is wiring, in document posted above, OK?
What firmware are you using?


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## marc02228 (Jan 15, 2011)

Tomaj said:


> I have the same problem. Communication between PC and main unit is OK, but there is no communication between main unit and CAN module.
> 
> Is wiring, in document posted above, OK?
> What firmware are you using?


Yes, wiring is correct.
Windows tool V1.8.4
BMS firmware V1.8.7

I think you should contact Mr. Paluckas from Elektromotus. He can also give you some advice how to set up the parameters.

If send me a your mail address, I could send you the files. It's actually quite intuitive, but some parameters might be tricky to set up.


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## Tomaj (Oct 3, 2011)

Yes please. Here is my email [email protected]

I have already contacted him, but no response till now.


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## Tomaj (Oct 3, 2011)

I have followed the instructions but no success, still no signal from battery pack/CAN modules

Could you perhaps export settings from EMUS control panel and send them to me?

Thanks


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## marc02228 (Jan 15, 2011)

Did you attach the 120Ω resistor from the CAN high to CAN low wire?
Is any of the BMS cell modules green led on for a short time?
I think I saved my setup somewhere, I'm gonna check it tomorrow.


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## marc02228 (Jan 15, 2011)

I'm not sure, if this is a setup file and if it is, I don't know if it's the correct one. Just give it a try.

Edit: I can't attach it here. Just sent you a mail.


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## Tomaj (Oct 3, 2011)

Found the issue, one cell module is defective
All others are working properly and communication between CAN modules and main unit is now perfect. Now I just have to wait for new module

Thanks for your help.


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## cpct (May 31, 2012)

Hi,
Where did you find firmware 1.8? On their downloads section, there is only up to 1.7 ?


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## marc02228 (Jan 15, 2011)

Got it by mail, when I told them about my problems with the CAN modules...


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## watchimgo (Aug 30, 2011)

Tomaj said:


> Found the issue, one cell module is defective
> All others are working properly and communication between CAN modules and main unit is now perfect. Now I just have to wait for new module
> 
> Thanks for your help.


How did you determine which module was defective? I have a 32 cell pack that isn't communicating and I'm not sure if one of the cell modules may be bad.

Thanks for any help you can give.


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## cpct (May 31, 2012)

watchimgo said:


> How did you determine which module was defective? I have a 32 cell pack that isn't communicating and I'm not sure if one of the cell modules may be bad.
> 
> Thanks for any help you can give.


You should start connecting the control unit to the bottom cell module (TX I suppose). Then the green leds on the cell modules that receive something will flicker every 5s.
For example, if the communication wire between cell 10 and 11 is missing, the first 10 cell module LEDs will blink and the rest after that stays dark.

But the control unit will only establish communication once the "loop" from bottom to top module is completed.

This process is also explained somewhere on their wiki page.


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## watchimgo (Aug 30, 2011)

cpct said:


> You should start connecting the control unit to the bottom cell module (TX I suppose). Then the green leds on the cell modules that receive something will flicker every 5s.
> For example, if the communication wire between cell 10 and 11 is missing, the first 10 cell module LEDs will blink and the rest after that stays dark.
> 
> But the control unit will only establish communication once the "loop" from bottom to top module is completed.
> ...


Thanks for the reply. I should have explained that I am using two CAN modules to communicate with the two sections of the pack. Each CAN module is connected to 16 cells in series. I tried connecting one of the CAN module to the bottom cell and powering it, but saw no blinking from the cell. Of course I also tried connecting the entire pack with the same result. I'm using 2.0.16 firmware on the controller and 0x00000000 on the CAN modules. I tried updating the CAN module firmware to the most up to date v0.11, but it failed to update. Any other ideas?


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## cpct (May 31, 2012)

watchimgo said:


> Thanks for the reply. I should have explained that I am using two CAN modules to communicate with the two sections of the pack. Each CAN module is connected to 16 cells in series. I tried connecting one of the CAN module to the bottom cell and powering it, but saw no blinking from the cell. Of course I also tried connecting the entire pack with the same result. I'm using 2.0.16 firmware on the controller and 0x00000000 on the CAN modules. I tried updating the CAN module firmware to the most up to date v0.11, but it failed to update. Any other ideas?


Aha, ok, I have no experience with the CAN modules (yet).
Have you tried testing the pack/modules without the CAN module? At least that should already work.


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## Tomaj (Oct 3, 2011)

Hi guys!

Does anyone have problems with uploading CAN group module firmware?

It is just impossible Every time I try reports error Enter config mode failed.
I have the latest device firmware version. It has been just updated, check their website.


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## Lipo Louis (Oct 29, 2012)

I have the same problem, my system works if I use the normal bot isolators, but I can not get the CAN group modue to work. I tried 3 different CAN group modules.

Maybe I just use these bot isolators, what is so much better with a can group module ? Maybe to maintaining a battery pack and keep the car working with the other packs ?


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## Tomaj (Oct 3, 2011)

CAN modules work with 1.8 firmware, but not with 2.xx firmware
I use CAN modules because battery pack is separated in 3 boxes. Those modules reduce interference with other systems on the vehicle. You can easily connect them in parallel or series and monitor each pack separately.
This BMS is probably the best on the market. But with couple bugs and issues and also pain in the ass to program it correctly.


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## Lipo Louis (Oct 29, 2012)

Ok, so than I probably will use the latest firmware and pc software and use the bot isolaters, it is just one CAN wire to the other packs. You have to make a power wire from one to another pack anyway, this small CAN wire is not that bad.

One downside would be, when removing one of the 3 pack, you have to adjust the number of cells with pc software.


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