Simp BMS

[arber333]

@tom91
I have connected VW modules via can cables and supplied 12V. When i observe can traffic there is a steady stream of info.
However i noticed 2 problems.

1. When i start simpBMS i get 96 cells and errors! When i observed debugg screen i found system is counting 12 cells and 8 strings as it should, but it also shows cell 12 as 0V. I noticed it starts to count at cell 0?

2. Also i cant get any data from nextion display. I tried to connect to serial1 and serial2, reposition rx, tx wires, but nothing... Can you help me what could be a problem?

I am using latest VW software...
I didnt connect the modules together in a single 96S string yet. Would that be a problem?

[tom91]

1. When i start simpBMS i get 96 cells and errors!
2. Also i cant get any data from nextion display. I tried to connect to serial1 and serial2, reposition rx, tx wires, but nothing... Can you help me what could be a problem?

Please check your settings, you need to setup your battery to say there are 96 cells present. Check in the debug menu if it registered propperly that there should be 96 cells, if not please reset the value by sending the number infront of it.

Also check your serial output settings.

[arber333]

Please check your settings, you need to setup your battery to say there are 96 cells present. Check in the debug menu if it registered propperly that there should be 96 cells, if not please reset the value by sending the number infront of it.

Also check your serial output settings.

Ok! i see can values and i can read all cells inside terminal. BMS states "ready". But still i dont get any serial from LCD. How do i check my serial settings?
EDIT: Yes i am dumb!!! I managed to swap my GND and RX connection to LCD. Now i have everything working, yay!
tnx

[arber333]

I am quite satisfied now. I get accurate data for VW hybrid cells. My intention is to fit simpBMS in with the trunk battery of our Ampera in parallel with OEM battery. I will wire contactor with a diode in reverse to be able to charge rear battery with OEM charger.
While Ampera would start simpBMS will provide 2s (precharge) delay for additional battery contactor to close.
TomDB can you elaborate if i can add a 2s shutoff delay to simpBMS protocol. When enable signal (key on) would go off i would need to hold connection between both batteries open for 2s so charge equalizes after i stop the car. Ampera is very finnicky about charge transfer after stop.
How would i go about this in your code?

tnx

[tom91]

How would i go about this in your code?

https://github.com/Tom-evnut/VW-bms/blo ... WBMSV2.ino
Look for how it changes states.
example:
Ready state to drive and thus close contactors
Line 730

Code: Select all

if (digitalRead(IN1) == HIGH) //detect Key ON

You will need to add a timer comparison to wait until the time has passed before actually doing what is under this if statement. Same for shutting down.

[meman124]

Hello, i'm trying to adapt the simpbms software to use another cell management board (for Taycan modules; it sends all needed info via canbus).

Started from the Outlander fork (https://github.com/Tom-evnut/OutlanderP ... anderBMSV2) and figuered that i just replace the outlander CANBUS commands with the proper Canbus commands for my batterty modules.

I have the reference canbus messages for the outlander from the pdf from Tom (https://github.com/Tom-evnut/OutlanderP ... Canbus.pdf). I found the 3C3 ID in the code, but not the other IDs (6x1, 6x2 and 6x3)?

What am i missing?

Who can help?
Best regards,

Bart

[tom91]

You need to read the coding and understand it to change it. Have a look at how messages are interpreted. So look in the Ino and .h and .ccp files.

[meman124]

Hi Tom,
Thanks for the reply.
I got it working, till a certain point.
Now, when i change the code to read the canbus messages coming from the BGTW (that reads the CMCs from the Taycan Modules), the watchdog resets simpbms constantly. I have no clue why?

[LRBen]

Are there any plans to add the Outlander charger support?
Also is there any way to map values onto the canbus, such as max cell voltage or total battery voltage etc.

[m.art.y]

I would also like to ask if the SIMP BMS is the same hardware wise between Tesla and other options and if just the software is different? Also if I can set custom cell voltage target for balancing in the SIMP BMS Tesla (and others) option as I need to set 3.95V.

[tom91]

Are there any plans to add the Outlander charger support?
Also is there any way to map values onto the canbus, such as max cell voltage or total battery voltage etc.

Working on outlander support. Need to review moving the charger onto the same bus as the modules.

The values are already being broadcast as described in the user manual.

I would also like to ask if the SIMP BMS is the same hardware wise between Tesla and other options and if just the software is different? Also if I can set custom cell voltage target for balancing in the SIMP BMS Tesla (and others) option as I need to set 3.95V.

Yes all firmware versions use same hardware. Yes all parameters can be changed freely, please check manual for parameters available.

[Bigpie]

LRBen I've added Outlander charger to my fork, but I've got it on an SPI canbus module.

[LRBen]

The values are already being broadcast as described in the user manual.

Ideal. Sorry missed that part on the manual!

[LRBen]

LRBen I've added Outlander charger to my fork, but I've got it on an SPI canbus module.

Is that the space balls repo?

[Bigpie]

https://github.com/jamiejones85/VW-bms it's the vw one and uses different can libraries, but the actually outlander charger parts should be simple enough to merge in to the variant you're needing, cant remember the modules you're using.

[LRBen]

https://github.com/jamiejones85/VW-bms it's the vw one and uses different can libraries, but the actually outlander charger parts should be simple enough to merge in to the variant you're needing, cant remember the modules you're using.

Thanks I'll see if I can copy paste the relevant code and see what happens. In the meantime I can still use my VCU to control the charger with voltage data from SIMPBUS canbus. Going to use Tesla model S modules now.

[m.art.y]

I want to use 108S configuration and only charge to 3.9V on every cell just because I have extra cells and hopefully this would prolong the life of them. The idea is to use Tesla Model S slave boards on non Tesla battery modules and SIMP BMS. Would SIMP be able to handle 108S configuration on Tesla slaves or would Tesla slaves be happy when wired in such configuration? Thanks

[arber333]

I want to use 108S configuration and only charge to 3.9V on every cell...

The way i noticed with my 104S configuration is that cells under 4V are more reluctant to balancing effectively.

I dont think simpbms would mind the cell numbering, it is a master. But what would you use on the cell sides to get such high number. You have custom modules?

[m.art.y]

The way i noticed with my 104S configuration is that cells under 4V are more reluctant to balancing effectively.

I dont think simpbms would mind the cell numbering, it is a master. But what would you use on the cell sides to get such high number. You have custom modules?

What I mean is that I want to use Tesla model S BMS slave boards on a non Tesla battery modules (mine are 2P6S). I would just need to add extra 2 Tesla BMS slaves to have 108S.

My cells are older design, they are only meant to be charged to 4.1V max. I am currently driving with them stacked in a cab without any BMS so I can access and monitor them with a multimeter. I only try to charge to 3.95V max and they seem alright, of course I am not getting spot on voltages as these are old cells and they are not performing same, don't have same capacity, but I am getting max difference of ~30mV which I think is acceptable. My main worry is that some may have higher self discharge rate and over long time may drift well out of balance. So I am looking for a BMS solution that would allow me to monitor and correct any differences that develop.

[arber333]

.
My cells are older design, they are only meant to be charged to 4.1V max. I am currently driving with them stacked in a cab without any BMS so I can access and monitor them with a multimeter. I only try to charge to 3.95V max and they seem alright, of course I am not getting spot on voltages as these are old cells and they are not performing same, don't have same capacity, but I am getting max difference of ~30mV which I think is acceptable. My main worry is that some may have higher self discharge rate and over long time may drift well out of balance. So I am looking for a BMS solution that would allow me to monitor and correct any differences that develop.

True i have the same worry with Mazda cells. They have some selfdischarge...
But then if you are able to change simpBMS code i could convince you to go with Hankzor active balancers 24S with CAN bus. They work their magic immediately and can show cell values on bluetooth. It is really good for balancing old cells.
But if you want complete system you need a CAN master to connect them modules in a chain.
I am working on the CAN code for my DUE board.
viewtopic.php?t=2256

[m.art.y]

Hi, does anybody know if Simp BMS with Tesla slaves is balancing cells all the time or only during charging?

[tom91]

Hi, does anybody know if Simp BMS with Tesla slaves is balancing cells all the time or only during charging?

Anytime the highest cell passes the balancing voltage threshold.

[m.art.y]

Anytime the highest cell passes the balancing voltage threshold.

Great . Would it work with 108S setup (18 slaves). Also any chance to connect to serial terminal to adjust settings over wifi? Thanks

[tom91]

Great . Would it work with 108S setup (18 slaves). Also any chance to connect to serial terminal to adjust settings over wifi? Thanks

Have a read of the user manual, everything is very adjustable: https://github.com/Tom-evnut/SimpBMS

108 series no problem. No serial over wifi.

[m.art.y]

Have a read of the user manual, everything is very adjustable: https://github.com/Tom-evnut/SimpBMS

108 series no problem. No serial over wifi.

Thanks. Just wanted to ask how reliable the comms is between all the slaves and Simp master? Do we need to use shielded cable? Also how far can Simp be from the slaves - can it be 2-3 meters of cable?