Thanks for the tip.
I finally found the culprit : C0’s R36 resistor is 18 kOhm instead of 100 Ohm.
This resistor is inline with the LTC cell voltage reading input, so it explains why it’s off.
The microscope also confirmed he was probably the smoker one :
C1’s R36 has also a burn mark but still at 100 Ohm.
However, I can’t change a so tiny resistor by hand. Its life will end on the bench. 
Thanks for your time.
Oh sure you can! Just power it of first and its pretty risk free 
You just need two soldering irons or if you’re really quick you can do it with one.
I think one resistor is 100Ohm and the one next to it is 3.3k
I actually changed that on mine. 2nd from top is burnt.
Also, fixed burnt traces with wires.
These pics were taken in Jan 2019. Still working great!
What happend ?
I connected balance terminals – and probably accidentally switched on the VESCs – before I connected the power terminals to the VESC.
I am having an issue, my board does power on but as soon as I apply any acceleration, even without me standing on it. Diebie shuts down with the following error shown in the diebiems tool: “errPreCharge”
Any idea what that error should mean or what would be the cause of it?
I’ll bypass bms later today just to confirm that it is diebie that’s shutting down.
Realtime data and charging works fine btw.
Thanks
The Pre charge function enables a PFET:
Can you check on your PCB for any signs? like missing resistor or burnmarks.
From what I can tell from the datasheet of bq76200, the precharge is meant for a deeply depleted battery to set a lower current to not harm the battery. Its controlled by the MCU however. So not an automatic function.
In settings to my BMS I have the precharge output on true for discharge as well. Not entirely sure what it does while discharging since the series resistor R33 only handles around 3-5W. Maybe its used as kind of a softstart/inrushlimiiter before you can utilize full current.
I can help you with a step-by-step troubleshoot, given that you’re comfortable with probing your PCB with a multimeter
Thanks a lot. I’ll do a visual inspection later today, I don’t have a multimeter with me since I am on a vacation but surely I’ll update you once a take a look at it tonight.
Thanks.
On further inspection I think that the precharge condition from the BQ76200 in Diebiems case Isn’t used as described in the datasheet at all(trickle current), but implemented precharge for the discharge if that makes sense.
This is it. This is why there is a timeout paremeter.
ERROR Precharge is triggered when the BMS is in Precharge operation and the load voltage hasn’t match the battery voltage * a precharge percentage (“Minimum precharge factor” parameter).
This is pretty strange as normally this error occured at the startup…
Could you hook a PC to the DieBieMS for reading its state ?
I do that. Opstate changes from a standard powered on if I remember correctly to errprecharge the second I put my finger on my remote…
I have noticed that after it shuts down it won’t power up for a minute it two after that at all…
I am using push to turn in function. I am not using switch to turn the board on.
BTW the battery is fine. Cells are 3.8v each, so nowhere near low V cutoff.
That’s weird…
It appears from nowhere ? Or is it after a servicing/issue/setup change ?
I was riding really slow… Like 8-9km\h. Stopped to let some cars go by, and the board was off… Turned it again on pushed the acceleration just to see it off again…
It was a rough road tho. So a lot of vibrations…
I’ve opened the board, spinned the wheels and the loud puck like electric bang was heard. I’ve cought it on video…
I don’t see anything burned or missing btw now.
I’ve tried bypassing the BMS and the esc Turned on just fine.I have a spare diebie so I will be replacing it in a few days.
Is there anyone doing diebie repairs? I would like to send this one for inspection and repair if possible.
Thanks.
I can ship it back to me take a look if you can’t find anyone local.
PM me if you need.
This lill guy is hiding in the dark, so cant quite tell. But maybe I’m paranoid.
If you have a multimeter, please check, I’ve swapped it on all diebies so far, s’posed to be 15Ohm but usually fails and reads Mohm after awhile:
Since we’re discussing defect DieBieMSs here.
I have one that shows weird behavior during (regenerative) braking. If I try to slow down to much, my brakes cut out. It is definitely the BMS because with my other DieBieMS everything is fine.
Also the display did this when the brakes stopped working.
(I’m not sure if that is related tho. I found a lose data cable on the display)
Anyone with a DieBieMS experienced something like this before?
Those screens are very cheap and sensitive. Think I have one left that is alive.
You should try monitor the fault Diebiems for a error msg. Easiest way to find out whats wrong
