FlexiBMS Lite - Flexible Configuration BMS w/ CAN-bus

[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.

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[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

[ducktaperules]

@fessyfoo

Is this just a unity thing? or all vescs?

think it can work on any vesc that has a built in power switch. afaik it works on new vesc mk3 and stormcore too. just means that you dont need multiple switches for a system with more than one vesc.

[fessyfoo]

now I want to know why that works. but we keep derailing here.

[Darkie02]

@fessyfoo

I want to know why that works.

@Darkie02

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.

Because electronics take time to depleat there charge

[fessyfoo]

yeah. the resistor I get. how come connecting that 5v line switches the antispark switch on in the second unity. was that by design or accident? why does that work?

[Darkie02]

I think it’s more of a work around when thay realised something people would want to run 4wd and not have 2 switches

[ducktaperules]

@fessyfoo

how come connecting that 5v line switches the antispark switch on in the second unity

Its caused by the “roll to start”. Its designed that when the motors are spun and the system is turned off the voltage generated is fed into 5v line for the processor. As soon as there is enough voltage to start the main processor it boots and if “roll to start” is enabled the processor turns on its own 5v supply to keep it active. This start up 5v pulse can be caused by the motors or by any other external device.

[fessyfoo]

thanks all. my curiosity appreciates you. and sorry for the derail.

[Darkie02]

@SimosMCmuffin

Some of the critical components are on backorder

Did the back order come in yet? Did the shop get finished?

[Davewesh]

@SimosMCmuffin Any word on getting these in the States? in the market for a BMS and would prefer to pick up a community one if I can.

[Dreads]

Also interested as well. (Located in the states)

[prime]

I’m also in the market for a good BMS to put into 2 or 3 of my boards. @SimosMCmuffin any updates or chances of getting some units in the US?

[Plurf]

not in the US but interested as well

[Chricious]

Does somebody has an idea how I can connect the Flexi to Metr Pro?

[mackann]

Install the bms, use stl or usb to update firmware, connect metr to uart on vesc, connect bms to canbus on vesc and start charging

[Chricious]

And which firmware is the right one? (everything is connected already, just can’t enter the software)

[mackann]

Latest on github, 0.8