Evolve Carbon GT battery cells balancing

I just charged my battery up to 100% and decided to check the cells.

The cells are showing a little bit of a difference between voltages.

What's the acceptable tolerances between cells?

C1 (highest) is showing a 93 mV difference to C8 (lowest).

For some reason, the recycle count is high at 5535.

Thoughts?

 

How old is your board? You have a recycle count of 5535? Ride much or just an error

I believe you need to answer the recycle count first before I can answer that question.

They all seem close, but C1 seems as least healthy cell since its reached 4.2v first. Did you let your board sit on the charger overnight to allow it to fully balance?

 

I can't remember how to check the cells with my remote. Can I get a reminder? Was dropped on my head a few times....

 

The board was one of the first boards from the CGT batch, around mid year 2016. It was purchased brand new from Evolve.
Is the recycle count the number of times it has been charged? I thought that number was strange because I haven't ridden this board as much as Id hoped to have (only once a week or fortnight). So the battery has only been charged as required.

 

Ahh, must be an error then with the recycle count. In theory if you charged 25% four times the recycle count should turn over to 1, indicating one full discharge / charge cycle of the battery. Batteries are rated in age as well as discharged cycles for how long they are to last.

 

Its the theory we best have for that number:
battery's cell voltage stays always the same and recycle count always 0

However that could be wrong. Someone should hit Evolve up to get the true word from them. I don't know what else it would represent honestly.

 

Should I be concerned about the >5000 cycles? I thought these batteries only had a limited number of recharges (about 500-ish)? I bought this brand new, so I guess I'd want to know if it was a used battery.
Is the balancing of the cells an issue? After running it a bit, C1 is still consistently higher than the rest of the cells.

 

Its either we got the whole recycle count wrong, which a 'cycle count' for a battery is what we described earlier or its an error which we've seen before but not in your style. I wouldn't worry about it.

Did you let your battery sit fully charged on a powered charger overnight or two?

 

Yea, C1 seems to be a better performer, as it never gets to fully discharge in relation to the other batteries.
I like to keep balance within 100 mV of each other. Of course there are opinions, some tolerate more and some tolerate less. Like the others mentioned, keep it on the charger for several more hours and let the BMS do its thing, Then come back and report back again.
Your Recycle count could just be data corruption. If it bothers you, just call Evolve and have them replace your BMS, but this'll probably reset your count back to 0 for what it's worth.

 

I think you ment to say C1 was the worse performer. Unless I'm mistaken, his snapshot was after a charge looking at the voltage. Weaker cells will charge faster to their given rated voltage and discharge faster. Stronger / healthier cells charge slower or take longer to reach their rated voltage, since they can hold more energy, and discharge slower for the same reason. Only two points or times you can take that determine true cell health is during its fully charged state (100% SOC) and as near to empty as you can get with the discharged state (say 5%-8% SOC).

I agree with you, the 100mV is a good rule of thumb for cell balancing spreads.

 

I'm only speculating from what he said, saying that C1 constantly is at a higher voltage when discharging. Under this assumption, that would mean C1 is at a higher capacity. I do agree on the fact about a weaker cell charging faster and discharging faster as well. Just based on what he said, C1 never gets to discharge its full capacity due to the other cells.

 

I tried just leaving the charger on for an additional 6 hours after it reached full charge. Barely anything changed. All the cells were within + or - a few mV within each other.

How long should I let it go for?

 

Except for C1? If so, I'd call Evolve and convince them for a new battery.

 

Yeah...I think you're right.
Remote spat out a "maintain bat" message. What does that mean?

 

Hey guys! Same issue here Maintain Bat!
No idea what to do....
I read that it has to do with the balance between the cells and that you need to send the board to a maintenance center....seriously??? Any experience with this issue? Advice please!

 

...nooooo don't say that :-(
I live in the middle east, shipping will cost a fortune :-(

 

You should only have to send back the battery. Ask for a paid return shipping label, its their defect not yours. Your money was 100% working and functional and still is right? You're still under warranty I presume. Crappy battery cells is the culprit.

If this was some small company, I'd pay the shipping. However Evolve is quite big and can afford to give their customers a return shipping label to resolve an issue which the customer didn't create.

 

Thanks for your reply Wiztecy!

I have sent them an email, but no response yet. I will give them 2-3 more days before I start getting annoying on social media to get some attention. Not replying to customers who obviously have an issue isn't acceptable. I really hope they will help me sort it out. Anyways, as I will keep you all posted on whats happening.

 

Hi guys,
I'm new to the family and just got my board today, after charging for a few hours and then taking it out for a spin I received the same "maintain bat!" Error on my remote, I was hoping someone would be able to let me know what they ended up going to resolve the issues as I'm dying to get back on the board!
Thanks for your help

 

So it disappeared after I gave it a bit of throttle, don't know if that's all it needed but after riding for another hour on it it is yet to return!
Would still love to hear from anyone who has had the issue and resolved it in another way incase it returns