You can set it up to balance when not charging. Balancing should not be needed under normal circumstances. I have the balancing disabled completely on my Flexi.
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Yes I agree but I just killed my 25r pack over the last 1 1/2 years as I dident want to replace the bestech bms ran it with no BMS untill more smart BMS came available.
To me logically charge balance shoul be active from min cell voltage untill max cell drift or charger is removed.
Say I build a new pack and you pick cells with the same voltage with in the p group. Each p group will have a different voltage from experience this often differ by about 0.3V pack will charge in a few hours but the balancing could take a few days. By leaving the charger in dose it balance after the charge termination has activated?
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0.3V? Is that recycled cells? Any new li-ion cells I have purchased so far were charged at 3.4V ± 0.01V.
Not unless you set it up to balance when not charging.
From my experience, it makes sense to get the pack balanced initially. That can be done by enabling balancing when not charging and letting it sit for long enough.
After that you shouldn’t need balancing more than once in a few dozen charge cycles. If you do, that indicates a problem with your pack that you should address properly rather than blindly balance out the voltages.
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I desoldered it. I looked for a solder bridge. The only thing I can think of is that maybe a miniscule bit of solder that I couldn’t see bridged here. But it looks like they are meant to be connected.
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You can ask here if it’s related to the project.
Not at the moment, as I’m trying to figure out how exactly the wiring was done.
If ($17) alwaysBalancing is 0, then balancing only happens when a charger is connected even after hitting a charging termination event.
If you’re pointing to the charging current shunt resistor, the other end of it is meant to be connected to the BAT- pad.
those this work on stock firmware unity ? i can’t manage to get the data displayed.
also since i changed battery type to “flexi…” powering up the unity turn down the bms ?!? like it stop charging and no more lights
if i plug it in while the unity is already up, it does work, but i still don’t get anything displayed on metr (maybe i just messed the can bus pinout ?)
Picture of the setup would be helpful.
After changing the battery type to “flexi” in the Metr app, turning on unity seems to shutdown the BMS?
And this happens even while it’s charging (you should have status led green or yellow during charging)?
What happens if you are charging and you have disconnect the CAN-cable. Does turning on Unity do anything then?
I’ll take a picture tomorrow, but after some reading i realized i’m suppose to only connect can-h and can-l as for a two vescs
I did connect the four wires:
can-h > can-h
Can-l > can-l
Grnd > grnd
Ena > 5v
I guess that’s why i got weird behaviours, hope i didn’t fry anything though
Here what i did :
Plugged the charget onto the bms (i was surprise not to see the green led light up on the charger)
Plugged the psu in the sector
It started charging : two red light on the charger and green led on the BMS
Turned on the unity (with and external antispark)
All leds on both charger and BMS turned off, and the unity booted as usual (succesfully conected to the metr app)
After changing back metr setting to li-po, i got the same result,
i unplugged everything some few minutes and when i tryed again after it did not turn it off
I’ll try that tomorrow as well as disconecting the two extra wires.
Edit : is there a specific way to actovate can forwarding on ghe unity ? I didn’t found the option and assumed it was on by default
Don’t you want the opto enable as well so it’s powered on when the VESC is in use.
I can’t rember if the unity has a high or low side switch
so it was that, i inverted the sequence on the unity side.
It’s now working and well : i got the info displayed on metr,
i still have this powering on/off issue randomly, i’m trying to reproduce it and film but obviously now it’s not happening 
(i have the four wires routed from the bms to the esc)
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Ok, last one and i stop flooding this thread ahahah
Everything works fine on the bench,
but i noticed that the unity keeps blinking (realy dim though) even after i turn the antispark off as long as it is connevted by can
(even with only canh and call)
Is that ok/normal ?
Can’t rember how the unity anti spark works.
Edit. Never mined found it on the old forum @Deodand
This dose mean you have 2 return paths that has a bad habit of doing funky things with electronics. No idea what @SimosMCmuffin put in to avoid this
I tryed all of the configurations :
can-l and can-h : works only when charger conected as expected
Can-l can-h with ground only : doesn’t do shit
Can-l can-h with opto only : works 100%
All four wires : works 100%
But in all of those case i got the unity blinking with antispark (an external one, the stock one is fried) off
Even though in all configuration the blink pattern is different (always the same blue led but different time)
And the intensity of the light changes as well (l+h+opto has the lowest one, it’s so dim i saw it only when i turned off the light on the room, but it’s clearly a net pattern : three fast blink every two seconds, not only my eyes messing around)
That’s the one I used
What happened is the + and ground are connected but no high or low (wondering if it’s the unity can communication is backfeeding the LEDS)
The opto isolate is only there to turn the bms on when the vesc is on. It turns on when the usb or charger is conected otherwise
wouldn’t that impact on the esc life expectancy as it prevents it to go really off ?
yes it’s pretty cool to be able to log in real time which cells are used more when on use, it could help diagnose a connection going partially loose or other preventable failures
That be a unity issue if it’s what’s causing it. lack of filtering gates etc with in the unity. I wouldn’t exspect any support from Jasion and his latest company massive dick.
Hi Simons, i want to change my bms on my board and your flexi is very interessant.
I understood the functions of the flexi for balancing, but I didn’t understand how it behaves on the “max battery discharge current” is there a maximum current that can be passed inside the flexi or not?
would you have any available? what would it cost? I live in Italy
Thanks for your time
You need to bypass discharge to use flexi
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thanks man.
it would be enough to connect the battery to the flexi but also to have a direct connection between battery and Unity right?
