Simp BMS

[joromy]

Struggling to find a cab300 will a cab500 work or will o need to alter the code

I use cab500 works great, without any changes

[Ev8]

Struggling to find a cab300 will a cab500 work or will o need to alter the code

I use cab500 works great, without any changes

Awesome news thanks

[Bryson]

I'm running SimpBMS with a Tesla pack and a LEM current sensor, and when I walked out to my car today, I noticed that the nextion display on my BMS showed what appeared to be 214A flowing with the contactors still in the open, nonconducting, state. I pulled up the serial log which shows more like 2 million amps, with or without the current sensor plugged in. This leads me to believe something odd is going on with the current sensor input on the board.

Next I pulled the SimpBMS out of the car completely and connected via USB (no other connectors or pins attached) and my serial terminal is reporting 0mA, as usual. I didn't see any obvious shorts or open circuits on the board, tracing as best I could to the CAN Hi and Lo pins 4&9 of J5, so I'm not sure what to do next. Any bright ideas from the community?

[Bryson]

Looks like it was related to a low 12V battery. The 12V system is charged up and it's working properly again. Odd.

A great idea for a SimpBMS feature: low 12V detection transition to charge state using hysteresis or a timer to turn off. My DCDC is triggered on by feedback from the second contactor closing - an auto-charge would prevent the 12V battery from going dead!

I suppose I can also do that with another teensy feeding this teensy too

[JaniK]

Low 12V battery actually seems to be the biggest problem in a non modifed OEM EV world too.

So electric cars have electric issues, who knew.

[Ev8]

This weekend i am mostly having issues getting serial comms working to my nextion display from the stripboard prototype board I built, the code looks to be using serial2 which on the teensy 3.2 should be pins 9 and 10 for rx, tx, but no joy can anyone confirm ive got the pin assignments right?

[Bryson]

I just followed the setup guide. Connector J5, pins 5 & 10 for 5V & ground and pins 8 & 3 for tx & rx. Did you try swapping tx and rx? It can be confusing to get them right.

[Ev8]

Not using simpbms hardware yet testing things with a teensy 3.2 and strip board prototype before investing in hardware, so looking at what serial ports on the teensy I should be using, and yes I have tried swapping tx rx

[tom91]

There are so many options for items that can be wrong.

Pin 9 and 10 are correct. Check you set the simpBMS firmware to output display serial try resetting if it shows in the menu.

Nextion display needs to be flashed with the latest firmware from my github; https://github.com/Tom-evnut/SimpDisplay

[Ev8]

Thanks Tom!

[Ev8]

so csvdebug must = 1 to enable ()dashupdate (serial2.write) will check when back at work on monday

[Ev8]

so csvdebug must = 1 to enable ()dashupdate (serial2.write) will check when back at work on monday

Ignore this I didn’t spot the ! In csvbug != 1

So dashupdate runs when csvbug=0

So still no closer to discovering why my display doesn’t work, everything is up to date code wise at both ends I’m Using bmwphev firmware, I will take the display home and test it on the nextion simulator

[Ev8]

So I got nowhere trying to get the display to work, it responds correctly when sent commands via a ttl adapter,
I’m using serial2 pins 9 and 10 on the teensy with baudrate of 115200 set on the nextion and in serial2 begin, and I’ve read through the code again and again and am either missing the obvious or something is up, Tom you mentioned have I got serial display enabled in firmware, i can’t find how this is done in the bmwphev firmware? Any pointers before I give up!

[Jackk]

Hello All

Having a bit of trouble with my SIMP BMS and was wondering if all you highly intelligent people could lend a helping hand!

I am running 4x tesla modules split up into banks of two and for some reason when i connect to the serial interface it only recognizes one bank (two modules)
I'm pretty sure my wiring is correct and both banks are getting +5v. Question is how do I find out which bank is or isn't registering?

BMS status is ready but only registering half the pack!! any ideas??

Thanks!

[tom91]

Any diagram of your wiring? If you only got half the banks reading unplug to find the offending plugs.

Reading only half is very very strange and points to a wiring issue 100% due to the way information is daisy chained.

[Jackk]

Hi Tom,

thanks for your time, please check out my wiring and tell me if you spot anything off...
I cant see how pulling the plug to each module will work as its a daisy chain so if I pull the any of the plugs I will get no readings whatsoever as it breaks the circuit, what am I not understanding here?
Each module has a blinking LED. I presume that means power or comms?. another question does the HV circuit need to be connected, have had it connected and doesn't seem to make any difference....

Jack

[tom91]

LEDs blink a bit on first power application.

They will keep blinking during correct comms.

If only a few modules show up when wired like shown above it should mean comms do work but there is another issue.

Try using the reset switch on the teensy while the setup is powered on, this should have the LED on the Teensy turn off and then back on after a few moments. This may solve the issue, if it is down to the startup.

What software version is listed in your settings menu?

[Bryson]

Wiring looks incorrect based on the diagram above. It should always go pin 4/9 -> 2/7 from left to right.

Cables from connectors 2-3 and 3-4 need pin 2 moved to pin 4

[Jackk]

LEDs blink a bit on first power application.

They will keep blinking during correct comms.

If only a few modules show up when wired like shown above it should mean comms do work but there is another issue.

Try using the reset switch on the teensy while the setup is powered on, this should have the LED on the Teensy turn off and then back on after a few moments. This may solve the issue, if it is down to the startup.

What software version is listed in your settings menu?

Hi Tom tried to reset teensy but no joy - Firmware Version : 210331

[Jackk]

Wiring looks incorrect based on the diagram above. It should always go pin 4/9 -> 2/7 from left to right.

Cables from connectors 2-3 and 3-4 need pin 2 moved to pin 4

Hi swapped pins 2 to 4 on connector two and three and now getting fault...

BMS Status : 5 Error 0

Out:0000 Cont:0000 In:0000 Charge Current Limit : 0 A DisCharge Current Limit : 0 A

[Bryson]

How many modules is the BMS recognizing? All four?

[Jackk]

How many modules is the BMS recognizing? All four?

Only recognizing two modules (four wired up) . All four leds are flashing. Really at a dead end with this one as have checked wiring countless times... any more suggestions would be fantastic!

Jack

[boekel]

How many modules is the BMS recognizing? All four?

Only recognizing two modules (four wired up) . All four leds are flashing. Really at a dead end with this one as have checked wiring countless times... any more suggestions would be fantastic!

Jack

Jack, the way you wired (picture you posted earlier) you basically skip the middle two modules. the comms pins you connect to are connected top/bottom, so that's why you only see the first and last module.

the led's can flash even without anything connected, and they probably flash due to 5v being present.

Tom already wrote about your wiring error.

[Jackk]

Thanks boekel!

OK sorry if I'm being a bit stupid but what alterations to the RX and TX do i need to make on modules 2&3...

I tried Brysons suggestion but no joy!

Many thanks for your help!

[boekel]

Thanks boekel!

OK sorry if I'm being a bit stupid but what alterations to the RX and TX do i need to make on modules 2&3...

I tried Brysons suggestion but no joy!

Many thanks for your help!

look at the last module...where does that connect? the same should be done with he middle modules. so use pin 2 instead of pin 4