Recently my Ownboard Bamboo AT started not powering on. I thought battery died but upon closer inspection I found it was a simple BMS failure and fixed it easily.
If you have a bamboo board and your board doesn’t power up, this could be the fix you can do. Just sharing since I have heard many people having problems with Ownboard battery.
Update:. It seems clear to me now that the BMS Failure is caused by the USB module:
Some more insight into these packs. They’re made with 2S4P groups folded in the center attached to pcb’s they integrate the balance leads and wires into them. The balance leads all plug into the bms on both ends, which is pretty cool. The series connections between groups can be made with short jumper wires because the pcb’s carry current. The last PCB has the bms built into it which is neat but does make the constant battery/BMS issues they were having even more unfortunate.
Yours didn’t seem to be but some of their packs were fully potted into the enclosure. Essentially no fixing happening there. Other were half potted and the originals, also current one I believe, are mostly held in by double sided adhesive foam. I’m estimating something like 4 different battery versions at this point. The PCB’s even used to be yellow.
The USB module is fine. The reason you were getting 9V when it was plugged in is the same reason the esc wouldn’t power on when you then plugged it in without the usb port. The USB port is has no way to power off and was putting just enough drain on the battery to cause the BMS to fault.
So, while you fixed the problem by bypassing the discharge through the bms, you agree that its a bms faulting issue. How are you sure the bms is actually balancing the cells when charging and that they are balanced right now? A bms error is pretty major and you’d probably be better off addressing it by fully replacing the BMS, in my opinion. Which is difficulty since its built into the PCB.
Oh thank you so much for the extra information! That’s gonna come in real handy next time I mod my ownboard with vesc.
As far as charging it seems to work fine, the board was simply not turning on. But I will test out the board this week and closely monitor the battery. Yes may be best to replace BMS but I just hate waiting for parts.
I think if bms charging is faulty the battery will most likely not charge fully to 42v. If that happens i will definitely have to replace the bms. Cells should be balance charged if battery pack charged to 42 volts, if unbalanced it should be slightly less. Right?
yeah, more than likely your pack is pretty close to balanced if you’re still getting to 42V. The bms will likely shut down if a cell more than .25V overcharged, so it could still be unbalanced but not by a large amount.
Listen, bypassing the BMS is not a good idea for Li ion 18650 batteries! They might be unbalanced and get overcharged, overheat and even catch fire while charging!
We all charge through a bms or balance charger. We simply wire the discharge from the pack avoiding the bms so it does not throw us off the board in the event it faults.
Ok but in this case from Dreskateboard something is definitely wrong with the BMS and this could include the balancing function protecting cells from not being overcharged right?
And also the batteries will not be protected from over discharging or does the esc protect from that?
I did this as well on my board. Does this really bypass the BMS for discharge? @A13XR3 what do you think?
My pack is still functional…amazing.
Yes it does. I am doing another Ownboard BMS repair, bypassing BMS is recommended if using vesc with it so you don’t trip BMS
Agreed. I dont know what’s happening to the bms frankly but it faults at the slightest current draw and prevents the board from turning on. If this happens mid ride, pretty high chance youre going to a slide. While it’s potentially not the safest choice in terms of battery health bypass discharge its generally considered safer for the rider since you are eliminating a fail point in the system.
With the 3 ownboard packs I’ve personally removed and replaced all the cells were still in good balance the 2 packs were newer, less than 100mi, and had a very small voltage difference between cells. I’m pretty sure the failure on the bms is in the discharging circuit although I can’t confirm that.
Yeah most likely discharging circuit is faulty somehow and cannot handle the current.
I finally figured it out guys, Ownboard BMS is not bad the problem is actually the USB module that shorts and causes BMS to fail. Because my BMS failed without an explanation as I don’t abuse it or anything like that.
But after putting new BMS in Ownboard, it STILL WOULDNT CHARGE I WAS LIKE WTF. Getting zero volts out of charge port.
So I opened the board and disconnected the USB module connection and voila! Now it charges fine.
The USB module I believe can short very easily from any kind of moisture that gets into it. I let Ownboard know and they will probably fix it
But if you have an Ownboard Bamboo definitely disconnect the USB module as it will ultimately cause your BMS to fail.
my usb port never worked and i removed it when i put a vesc in. Maybe that’s why it’s still working after 1000+ miles.
Yup that’s probably why.
Here’s a video explaining it
Now I don’t need to feel bad anymore that I shorted my USB module while swapping the batteries 
Yeah the USB module is definitely causing all the BMS problems.
Hello guys,
Just want to say same thing happened to me, I was using the skate on a rainy day and suddenly the board turned off. When I tried to charge it, it wasn’t working. I found this post, unplugged the USB charging port, unplugged the battery, replugged the battery and it turned on again.
Thanks for the info!
Hopes this help someone else