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2020 Evoke Urban Classic BMS Issues

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nemonobody:
Hello,

Newbie here with some newbie questions.  ;D

I own a 2020 Evoke Urban Classic: https://www.reddit.com/user/NemoReviews/comments/tj3ci7/evoke_urban_classic_storyreview/?utm_source=share&utm_medium=web2x&context=3

When im riding, I see the following errors:

Charger overvoltage (most common)
Battery vol too low (2nd most common)
Mos overheat
Discharge MOS error
Discharge overcurrent
Discharge protection
Main connection failure (only saw this once)

I look at the AntBMS app and check the logs and it shows
"Single Overvoltage" 20 times
"Discharge monomer under voltage" 1 times
"Discharge Battery over temperature" 1 time
"Charging monomer overvoltage" 1 time

I think single overvoltage is referring to the cell and it might be exceeding the single overvoltage protection value set in the BMS app which is 4.2. Evoke has said it might be that the cells are not balanced. However, I already discharged the bike to less than 10% and left it to charge to full overnight, but I continue seeing these errors. I am balancing by running the bike to less than 10% since the bike is basically unridable (very slow). I then charge using an AC wall outlet and leave it charging overnight. I used to charge the bike using Lvl 2 charging, but I was told that charging on Level 2 cuts off power after the battery reaches 100% and does not allow the battery to balance.

I was also told that I need to completely bleed the battery to ZERO by using a heating rode and connecting it to the battery connectors. I am not sure how to do that or if that will make a difference. Please let me know.

Tonight, I am charging the bike from 30% SOC and leaving it to charge overnight and testing the bike again tomorrow morning.

Please let me know if the errors conclude a balancing issue or if something else is going on.

Thank you!!

Nemo

rgutt:
First up, discharging is not a requirement of balance lithium cells. And unless you want a really expensive paperweight, do not bleed your battery to 0, though hopefully the BMS would protect you from actually destroying your battery as long as you tried to discharge it across the distal side of a BMS-controlled contactor.

If you do have a large cell imbalance and depending on the balancing technique used by your BMS, it can take more than an overnight charge to correct it. Do you have any way to see the actual max and min cell voltages?

By the way, about the only reason to ever fully or near fully discharge a lithium battery and fully recharge it in a single shot (excluding just making a long trip obviously), is to possibly let the SOC calculation recalibrate itself. It does nothing good for the battery itself.

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