FlexiBMS Lite - Flexible Configuration BMS w/ CAN-bus

sucks :frowning: so we are all stuck without good small charge only bms for VESC for now. :weary::weary: at least those that need 16-18s :sob::sob:

get in this thread, 16s charge only bms. no canbus or anything tough.

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There is something weird going on as the BMS shows the battery voltage on the charger port. This would indicate that the charger FETs are likely damaged, because when the BMS goes into faultState it should shutoff the charging Fets and therefore shouldn’t show any voltage there, especially with no charger connected. This is also the reason for the double green chargingEnd blink, as the BMS detects a voltage on the charger port, but finishes immediately, as there is no current flow.

Assembly is currently underway.

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Nice. :star_struck:

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Hi, I’m wiring my Flexi and my sensor wires looks like this:

Connector 0 goes to negative terminal, next balanse wires, up to positive battery terminal. I have a question regarding balance wires. Let me explain my picture… connection between those 2 batteries (thin black) is spot welded, bent nickel strip. there is additional nickel strip coming from that connection (green) but from negative side (safer, no short). Does it matter if balance wire goes from positive or negative terminal ? They are connected in series so it should not make a difference.

Since they’re electrically connected (same voltage) anyway, it does not matter.

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No; like you said, it’s safer on the negative side because if something vibrates/rubs through the cell’s wrap then it’s not a short.

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Is there a 3d model of the OG flexi? Or an enclosure other than the one with the cable holes on top?

So I have put in the work and designed my own case, here is the link to thingiverse. Feel free to use this.

Link

Pics:

Cheers

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I really love this case, is there a way you could edit it just slightly (or post the .step/.ipt) so it would work with both vertical and horizontal plugs? I have a mix of both and it should be as simple as making the lid cutouts deeper by 2mm on the balance side and 3.5mm on the CAN side.

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Sure, updated the thingiverse page with an updated lid version, now supports both horizontal and vertical ports. Could be a while till it shows up though, so check back later if it processed.

Edit: fuck it, takes to long. here’s the .stl.
Flexi BMS lid vert. + hor. ports v6.stl (83.9 KB)

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Awesome thank you so much! I’ll print it off now and let you know if it works.

Could you also make a version with a thermistor plug cutout. That would greatly be appreciated.

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You guys seriously need to learn how to alter .stl files, its not that difficult. :rofl:

But seriously, just thread the wires through the cooling slots.

Yeah yeah, still sucks working with them :joy:

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Honest question, how is that possible :joy:

What software do i need to use to edit stl in a way like cad drawings can be edited? ( Im used to Catia )
Like dimensions, sketches etc

Most software is pretty bad with STL files, therefore many people just use tinkercad for small edits.

Teach me because every time I try I end up just measuring stuff and remaking it “by eye” lol

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It should be a law that if you put up a stl file on thingiverse, a cad file should be supplied as well😂

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