FlexiBMS Lite - Flexible Configuration BMS w/ CAN-bus

[magharees]

@Pimousse was kind enough to craft a manual with all the answers. I won’t back link to the yeuch place directly

https://drive.google.com/file/d/1cAlaAxA7yCMaTV4SlLBUlxvXA49OH1vI/view

And of course the readme on github

DieBieEngineering/DieBieMS/blob/master/README.md

Also found this just now

dsoto/DieBieMS-Manual/blob/master/troubleshooting.md

You know @b264’s favorite knowledge place duckduckgo.com

@SimosMCmuffin apologies for the derail

[SimosMCmuffin]

Here’s the current list of available configurable parameters on the BMS and their descriptions.

SimosMCmuffin/FlexiBMS_Lite_FW

[ducktaperules]

its crazy that this motorbike carries the charger around all the time, just to save it shipping with a large external charger.

Wonder if you could make your charger so it mounts on your board for long group rides, saving space in your backpack.

[Murloc992]

@ducktaperules

Wonder if you could make your charger so it mounts on your board for long group rides, saving space in your backpack.

For top mounted MTBs I think it would be possible. Like a piggy-back charger stacked on the main box.

[JTAG]

Such much love , and from others also , thanks!

Just finished my backlog of BMS repairs, not that many just a few, most failed due to bad wiring or bad packs, but that kind of failure will damage any BMS connected to it. The problem with balance wires is that they can deliver quite a bit of current, also when that is undesirable.

[SimosMCmuffin]

They be golden.
Production boards are here with their ENIG ( Electroless Nickel Immersion Gold ) finish.

Some of the critical components are on backorder (battery stack monitor), but I have enough of my own personal inventory that I can start the assembly now and make what I can with the components I have on hand.

Storage discharging has been implemented in the FW and more can be read over here:

FlexiBMS Public Support, Feature & Troubleshooting Thread

0.7 is out. Bug fixes, improved balancing temperature handling and storage discharging implemented. Parameter list updated Commands list added Quick start guide (will likely be expanded later) Serial terminal setup guide Serial terminal use guide

Also found a little improvement for the active mode current consumption with a better resistor choice.

[SimosMCmuffin]

I have some boards assembled, but I’m making/developing some improvements to my PnP machine.

Auto feeder proof of concept

[potatocoder]

@SimosMCmuffin So When Can I start to get my hands on ones of those boards?

[fessyfoo]

@mackann

On Focbox Unity i add a 4,7ohm 1w resistor on 5v canbus cable for 2 unity on 4wd to make it work safe

why a resistor on the 5v line? that’s not the same as the terminating resistors is it?

what does safe mean in this context? safe from blowing each other’s can circuits? or safer can signaling quality? or??

why connect the 5v line at all? I thought he canbus just needed the two CAN wires connected?

[ducktaperules]

IIRC connecting the 5v lines means that when one unity powers up it’s 5v supply this connection also allows the other unitys 5v line to get powered up, causing both unitys to boot together.

The resistor means it if any faults occur then your not causing a dead short on the 5v line which could cause damage the unitys internal 5v supply.

[glyphiks]

@ducktaperules

connecting the 5v lines means that when one unity powers up it’s 5v supply this connection also allows the other unitys 5v line to get powered up, causing both unitys to boot together.

Fun fact: if you have push to start disabled, this doesn’t work.

[fessyfoo]

Is this just a unity thing? or all vescs?

Why do they need to power up together?

is this a precaution against the fabeled canbus chipset burnout from powering vescs on at different times or what is it protecting against?

[glyphiks]

Its a way to get two unities to boot up from one unity switch. So yeah, specific to unities

[Darkie02]

@fessyfoo

that’s not the same as the terminating resistors is it?

The problem is the VESC has not implemented CAN BUS properly is shortened bastardised vershion from what I understood.

@fessyfoo

why a resistor on the 5v line?

I think the resistor between the unity’s was some thing to do with useing 1 switch to turn on and off both unity’s. With out it when you pressed the switch the 1st unity would turn off but the 5v raile on the 2nd would take over and boot up the 1st unity again. This would leave you stuck in a cycle of not been able to shut down.

Bringing this back to topic I believe the DieBieMS had a solder bridge on the PCB the you could add or remove depending if it was end of line or in between VESC that did have a resistor unsure on the FlexBMS

Sorry that I keep comparing Flex BMS @SimosMCmuffin to DieBieMS but it’s the only thing I know that works in a similar way. I see both have there advantages in there own way not as a copy

[glyphiks]

Ahhhh that explains it. The resistor is there to stop the loop on power off

When i first set mine up they powered on but would not power off. I swapped out the whole can cable/resistor and it worked like a charm

[SimosMCmuffin]

@Darkie02

Bringing this back to topic I believe the DieBieMS had a solder bridge on the PCB the you could add or remove depending if it was end of line or in between VESC that did have a resistor unsure on the FlexBMS

Sorry that I keep comparing Flex BMS @SimosMCmuffin to DieBieMS but it’s the only thing I know that works in a similar way. I see both have there advantages in there own way not as a copy

@SimosMCmuffin

I’m not quite sure how the CAN-bus will behave if you have multiple devices (>2) on it and multiple of them have termination resistors. Normally the termination resistors are only used at the end of the cable chain. So just in case I moved the termination resistor a little bit on the board and added an easily cuttable open trace, so if there is too much termination on the bus, you can just cut that little trace to disconnect the termination resistor and solder bridge it back on later if it’s needed.

image1920×949 270 KB
[/quote]

[Darkie02]

@SimosMCmuffin

solder bridge it back on later if it’s needed.

I don’t know if I would be able to solder on a pcb trace (never done one before) would creating a bridge hear work?

[SimosMCmuffin]

You can bridge it that way too