[EcoDrift.ru] Ninebot Z10: A Diagnosis of Common Issues

[Ziiten]

15 hours ago, Girth Brooks said:

I just got mine from We Unicycle on eBay. They also have an Alli store as well. I got a new battery from them for my Z10 with no issue. It was at 96% on both batteries upon arrival with both LED lights flashing blue.

Just heard back from the seller; warranty was 6 months, so out of luck there.

[Girth Brooks]

10 hours ago, Ziiten said:

Just heard back from the seller; warranty was 6 months, so out of luck there.

I was not the happiest to not have mine covered under warranty either. I was initially going to sell mine without a battery and get what I could for it. I ended up buying a new battery instead after a few months thinking on it. I missed my Z10 too much to sell it for scrap or leave it collecting dust.

[Ziiten]

@Girth BrooksYou probably said it already, but what happened to your original battery. Same problem as I had?

Edited August 9, 2019 by Ziiten

[Girth Brooks]

1 hour ago, Ziiten said:

@Girth BrooksYou probably said it already, but what happened to your original battery. Same problem as I had?

The BMS board failed in mine.

[Rotciv]

3 hours ago, Girth Brooks said:

The BMS board failed in mine.

What did you do with the broken battery? I would like to know how the battery pack is put together and to see if the cells can be replaced. Would you like to donate your broken battery to be taken apart and studied?

[Ziiten]

It appears, it not just the cells 1 an 2 of the 2nd battery. Did a full recharge (about 10 h), turned the wheel on and did about five meters hovering back and forward and this is what I got. The first image is taken right after I got the cell voltage difference warning, the other image is about five minutes after the wheel being turned off (about 5 secs turned off will do it too). I wonder if the problem is the battery after all or something in the bms.

Edited August 10, 2019 by Ziiten

[Chriull]

1 hour ago, Ziiten said:

I wonder if the problem is the battery after all or something in the bms.

It's a bit like looking into the crystal ball, but this really could be the bms...

Cell 1 and 2 of Battery 2 leveled( balanced) out quite some difference by charging and then within some short drive battery 1's cell 1 and 2 of battery 1 are messed up and leveled again within 5 minutes...

(Or did you swap the battery packs?)

 

[mrelwood]

I’m having hard time believing that the cells would actually get that much out of whack, and then suddenly correct themselves.

1) The BMS should never let any of the cells get past 4.2V, so the charge should’ve stopped when the highest cell is at 4.2V.

2) @Ziiten’s issue is sometimes in pack 1, sometimes pack two.

I suspect that the issue is with the cabling going from BMS to the mainboard, or in the mainboard itself. Interestingly, the issue seems to be always at cells 1 and 2, so I’d guess the packs have connectors or board traces where the leads for cells 1 and 2 of both packs are going next to eachother. That’s where I’d look first if I were to open the wheel up.

[Planemo]

Agreed. I would love to have a scrap Z10 battery to pull apart and check all the points you raised. Could also check individual cells voltages at that point as well to isolate the problem/s.

[Leonardo Deleon]

I have been experiencing the same problem. But for mine is cell 1 of battery 2. I can ride the wheel until it gets to around 70% of battery, when it starts getting unbalanced. Sometimes it can unbalance during the ride, I turn it off and on again and it reverts. Should I check any cables?. 

[Ziiten]

2 hours ago, Leonardo Deleon said:

I have been experiencing the same problem. But for mine is cell 1 of battery 2. I can ride the wheel until it gets to around 70% of battery, when it starts getting unbalanced. Sometimes it can unbalance during the ride, I turn it off and on again and it reverts. Should I check any cables?. 

I have this problem in both batteries, but usually it is battery 2. But it is always a big voltage difference between cells 1 and 2, no. 2 showing the higher voltage. Sometimes I can ride for long rides without  any issues, whereas other times I get the problem after 2 meters from starting the ride with a 100% battery.

I have discussed this with @mrelwood and it is his opinion that this isnt necessarily a battery issue, but rather a loose connection somewhere. So, yes it might be a good idea to check the cables and their connectors. Opening the battery and especially accomplishing something useful with it might be a more complicated matter.

[Leonardo Deleon]

1 hour ago, Ziiten said:

I have this problem in both batteries, but usually it is battery 2. But it is always a big voltage difference between cells 1 and 2, no. 2 showing the higher voltage. Sometimes I can ride for long rides without  any issues, whereas other times I get the problem after 2 meters from starting the ride with a 100% battery.

I have discussed this with @mrelwood and it is his opinion that this isnt necessarily a battery issue, but rather a loose connection somewhere. So, yes it might be a good idea to check the cables and their connectors. Opening the battery and especially accomplishing something useful with it might be a more complicated matter.

Have you checked the connections on yours @Ziiten ? Are you still having the issue?

[Leonardo Deleon]

Example after I get to work

[Ziiten]

Looking at your cells' status it seems indeed that the problem cells are 0 and 1 whereas I have 1 and 2.

I havent yet investigated the wiring but that is being planned with the help of someone who actually knows what he's doing @mrelwood

Edit: Forgot to ask you: has your wheel taken any serious beating like when falling or something similar. Mine has flown arournd quite a lot, so I would not be surprised of some loose connections.

Edited August 22, 2019 by Ziiten

[Leonardo Deleon]

2 hours ago, Ziiten said:

Looking at your cells' status it seems indeed that the problem cells are 0 and 1 whereas I have 1 and 2.

I havent yet investigated the wiring but that is being planned with the help of someone who actually knows what he's doing @mrelwood

Edit: Forgot to ask you: has your wheel taken any serious beating like when falling or something similar. Mine has flown arournd quite a lot, so I would not be surprised of some loose connections.

I did have some falls here and there. And I also notice that after some kinds of bumps/curbs/potholes it can trigger this unbalanced state. Riding today it was triggered three times. But turning off and on again a few times makes it balanced again somehow. Really strange

I opened up my wheel to check the connections, but don't see anything out of place.

[Leonardo Deleon]

I haven't opened the battery as it's a bit more dangerous. But the problem is likely there 

[Ziiten]

I have also noticed that this occurs often at bumps and similar. I guess these bumps cause current peaks, which makes the faulty cell to dip and cause an alarm. I am starting to think it is a battery issue - we have just had bad luck with the batteries.

[mrelwood]

20 hours ago, Leonardo Deleon said:

Example after I get to work

Just noticed, the total voltage for both batteries is nearly identical, yet the one with the issue reports about 750mAh more capacity left. For some reason the software is unable to calculate the battery capacities correctly. Intermittent connection could do that, but I don’t think a dying cell would. And a dying cell doesn’t get healthy from a wheel reboot. And a battery cell doesn’t start dying (over and over again) from riding normally to a bump. So far I’ve seen nothing that points to a battery failure.

[Leonardo Deleon]

20 hours ago, mrelwood said:

Just noticed, the total voltage for both batteries is nearly identical, yet the one with the issue reports about 750mAh more capacity left. For some reason the software is unable to calculate the battery capacities correctly. Intermittent connection could do that, but I don’t think a dying cell would. And a dying cell doesn’t get healthy from a wheel reboot. And a battery cell doesn’t start dying (over and over again) from riding normally to a bump. So far I’ve seen nothing that points to a battery failure.

@mrelwood If the battery is not failing, where could be a culprit that a connection is bad? Inside the battery? On the BMS? On the motherboard?

I thought if the problem was on the battery it would show up consistently, but it always changes when it gets unbalanced. I would like to rely on the wheel for commuting, right now I don't know the next time is gonna tilt me back or throw me off

[mrelwood]

2 hours ago, Leonardo Deleon said:

@mrelwood If the battery is not failing, where could be a culprit that a connection is bad? Inside the battery? On the BMS? On the motherboard?

Any of those, or on the cables and connectors themselves. I haven’t been inside a Z10 (yet?), so unfortunately I can’t offer any specifics where to start from.

Quote

I thought if the problem was on the battery it would show up consistently, but it always changes when it gets unbalanced.

My thoughts exactly. There is no route for the cells to get that badly unbalanced and then ”fixed” in such a short perioid of time, unless the wiring that is in place for balancing the cells has a short. Which again would mean that it’s not an issue with the battery cells themselves.

Quote

I would like to rely on the wheel for commuting, right now I don't know the next time is gonna tilt me back or throw me off

The situation is very unfortunate. I will of course post here as soon as we have a look inside @Ziiten’s wheel, but we don’t yet have a date planned for the checkup.

Edited August 24, 2019 by mrelwood

[Leonardo Deleon]

1 minute ago, mrelwood said:

Any of those, or on the cables and connectors themselves. I haven’t been inside a Z10 (yet?), so unfortunately I can’t offer any specifics where to start from.

My thoughts exactly. There is no route for the battery to get that badly unbalanced and immediately ”fixed” in such a short perioid of time, unless the wiring that is in place for balancing the cells has a short. Which again would mean that it’s not an issue with the battery cells.

The situation is very unfortunate. I will of course post here as soon as we have a look inside @Ziiten’s wheel, but we don’t yet have a date planned for the checkup.

@mrelwood I'm buying a new wheel. Do you think I should keep mine for a possible fix or sell it for scrap?

[mrelwood]

5 minutes ago, Leonardo Deleon said:

@mrelwood I'm buying a new wheel. Do you think I should keep mine for a possible fix or sell it for scrap?

I really can’t say either way. It is possible that we will find a connector that seems prone to failing in a certain way, in which case a fix might even be reasonably simple.

Then again it is possible that I’ll never even get to have a look inside the Z10. So I really can’t tell you to wait for my findings either.

Either way the shop you bought the wheel from should be let know about the issue. I’d give them a chance to fix the issue before losing money on selling your broken wheel.

[Ziiten]

12 minutes ago, mrelwood said:

I really can’t say either way. It is possible that we will find a connector that seems prone to failing in a certain way, in which case a fix might even be reasonably simple.

Then again it is possible that I’ll never even get to have a look inside the Z10. So I really can’t tell you to wait for my findings either.

Either way the shop you bought the wheel from should be let know about the issue. I’d give them a chance to fix the issue before losing money on selling your broken wheel.

@Leonardo Deleon  I am most likely buying a new wheel as well, possibly a Nikola or KS 16X. However, I think I will do the purchase next spring, because ordering now by the time I would get it the riding season would be almost over.

I considered buying a battery for the Z10, but that could turn out being a waste of money (+800€) if the fault was somewhere else, which is quite likely.

@mrelwood My car is being rented all the time so I have to get back to you whenever I have it for a weekend preferably. Or I could just ride the wheel to you and hope for the best. After all, you are only about 15 km away, so I should still manage that without too much of issues.

[RoberAce]

 

[Ziiten]

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Edited August 25, 2019 by Ziiten