V11 Voltage Delta between Battery 1 and Battery 2

[Buddywoof]

Hello, 

I have a new V11.  This is my 2nd one.  On this new one, after a full charge there is a relatively large difference between Battery 1 voltage and Battery 2 voltage.  As you can see in the screenshot, the difference between Battery 1 and 2 is up to 0.4 volts which I feel is significant.  I'm thinking these carefully balanced high quality cells from LG should have a very small delta (maybe 0.1 volts) given these are 20-cell packs (20 x 4.2 volts = 84 volts).  I suspect 1 of the 20 cells from Pack 2 is bad.

I'm wondering if other V11 owners are seeing such a delta between the two battery packs (battery 1 and battery 2)?  You can check this in the inMotion app-->settings-->About Vehicle-->Battery Pack Detail.  Thanks for your feedback.

Screenshot:

https://drive.google.com/file/d/1vxZh1qZjCyD8RnRDQz-1ECtBIOPKgqo4/view?usp=sharing

[Tawpie]

something isn't right there, I prefer to see 0.1v difference 'at most' before I connect two packs in parallel. can you ask your reseller?

[Buddywoof]

Thanks for the reply.  I will send an inquiry to my supplier.  

btw - these batteries are rated 1500Wh.  If everyone getting the 1500 Wh when measured from full charge to tilt-back after battery depletion? 

[mrelwood]

0.4 volts definitely sounds worthy of investigating that everything is ok. But a dead cell (group/pair) would mean a difference of 4.2 volts.

 Is this a one time occurrence, or is it like this after every charge? If it was your first charge, I’d ride the wheel for just a short while, and once at roughly 90%, charge it to full again. I always leave the wheel to the charger for 1-3 hours after the charger(s) turn green to make sure that the cell groups get as much balancing as possible.

3 hours ago, Tawpie said:

something isn't right there, I prefer to see 0.1v difference 'at most' before I connect two packs in parallel.

Me too. But the packs are not hard wired parallel in V11. They are separately connected to the board, which has control logic for the pack balance. That’s how it’s possible to report the pack voltages separately in the first place.

47 minutes ago, Buddywoof said:

btw - these batteries are rated 1500Wh.  If everyone getting the 1500 Wh when measured from full charge to tilt-back after battery depletion? 

No-one is, on any EUC. The wheels’ reported capacity is calculated directly from the reported cell capacities. But all EUCs prevent depleting the battery well before the 2.5V, which is usually the low limit that is used for the capacity calculation. The V11 won’t let you ride once the cell average reaches down to 3.15V.

I remember measuring a maximum of 1300Wh (or was it 1100Wh?) being charged into a 1600Wh MSX.

[Buddywoof]

1 hour ago, mrelwood said:

0.4 volts definitely sounds worthy of investigating that everything is ok. But a dead cell (group/pair) would mean a difference of 4.2 volts.

But the packs are not hard wired parallel in V11. They are separately connected to the board, which has control logic for the pack balance.

Hi, thanks for your feedback.  It is very much appreciated.  I don't think the cell is completely dead but rather defective so it cannot charge to full capacity which is why at full charge, the battery pack #2 shows 83.8 volts instead of 84.2 volts like battery pack #1.  At least that is my theory.

You might have a point in that the packs are measured by two separate boards which might cause such a difference.  I'll observe the pack for a couple of weeks to see if the issue remains.

Again, thanks for your valuable feedback!

 

 

[Buddywoof]

17 hours ago, mrelwood said:

I always leave the wheel to the charger for 1-3 hours after the charger(s) turn green to make sure that the cell groups get as much balancing as possible.

 

So in the next cycle, I tried leaving the charger on after the charger turned green for 3-4 hours and the result is I see up to 1 volt difference (battery 1=84.7 volts and battery 2=83.7 volts).  When I left the charger on, Battery 1 seemed to get overcharged because battery 2 never gets charged beyond 83.8 volts and the charger tries to keep charging battery 1 because battery 2 isn't fully charged (or at least tries to balance the two battery packs as it keeps charging).

Screenshot:

https://drive.google.com/file/d/1aPmqcOpQMZy7ZoFmq76gOm4ECuT576UB/view?usp=sharing

Questions:

What voltage do your V11s charge to for battery 1 and battery 2 with charger still connected after green?  Isn't my battery 1 showing up to 84.7 volts too high?

So what do you all think?  Battery 2 is defective?

Edited November 17, 2021 by Buddywoof

[RagingGrandpa]

13 minutes ago, Buddywoof said:

after the charger turned green for 3-4 hours and the result is I see up to 1 volt difference (battery 1=84.7 volts and battery 2=83.7 volts)

That sounds like Battery 2 disconnected itself due to cell imbalance. That's worth investigating.

If it were my wheel, I would:

1. Open the controller box
2. Disconnect both batteries
3. Measure each battery's voltage (carefully!) with a multimeter, to confirm any voltage difference between them
4. Connect only battery 2 (the lower-voltage one) to the controller
5. Turn on the EUC, verify normal operation, record the app status
6. Start a voltage recording with EUC World (or a voltage graph in iOS Darknessbot), and then charge the EUC with the controller "on" and still only battery #2 connected
7. Stop the recording (or screenshot the graph) after the charger light turns green, and study the voltage value that occurred.
8. (Share the logfile here for more feedback)

Don't ride the EUC with only one pack connected- if there is a fault, the EUC could turn off unexpectedly and cause you to fall.

.02

[Buddywoof]

3 hours ago, RagingGrandpa said:

That sounds like Battery 2 disconnected itself due to cell imbalance. That's worth investigating.

If it were my wheel, I would:

1. Open the controller box
2. Disconnect both batteries
3. Measure each battery's voltage (carefully!) with a multimeter, to confirm any voltage difference between them
4. Connect only battery 2 (the lower-voltage one) to the controller
5. Turn on the EUC, verify normal operation, record the app status
6. Start a voltage recording with EUC World (or a voltage graph in iOS Darknessbot), and then charge the EUC with the controller "on" and still only battery #2 connected
7. Stop the recording (or screenshot the graph) after the charger light turns green, and study the voltage value that occurred.
8. (Share the logfile here for more feedback)

Don't ride the EUC with only one pack connected- if there is a fault, the EUC could turn off unexpectedly and cause you to fall.

.02

Thanks for your feedback.  I guess I will need to learn how to take one of these apart.  I'm hoping battery replacement is not nearly as complex as a wheel or motor change!

btw - what voltage should battery 1 and battery 2 charge to after turning green and charger left on?

[Tawpie]

7 hours ago, Buddywoof said:

what voltage should battery 1 and battery 2 charge to after turning green and charger left on?

There is always some possibility that the voltage measurement made by the wheel can be off, these things are notoriously imprecise. You want to open the wheel, disconnect both batteries, turn the wheel on to discharge the control board capacitors, then use a multimeter to CAREFULLY measure the battery voltage at their connector. They should be within 0.1V of each other, and within a tenth or two of 84V

[Buddywoof]

4 hours ago, Tawpie said:

There is always some possibility that the voltage measurement made by the wheel can be off, these things are notoriously imprecise. You want to open the wheel, disconnect both batteries, turn the wheel on to discharge the control board capacitors, then use a multimeter to CAREFULLY measure the battery voltage at their connector. They should be within 0.1V of each other, and within a tenth or two of 84V

Thanks for the suggestion.  I might just try that.  I'm also waiting for the vendor to provide the next steps so I'll wait for that.  btw -   Is getting to those connectors for voltage measurement relatively easy and is there a video guide anywhere? 

[Tawpie]

ugh. I might check with v11 owners on how much of this has to be done to get to the control board, but the battery disconnection happens at about 2:45 

 

[mrelwood]

16 hours ago, Tawpie said:

ugh. I might check with v11 owners on how much of this has to be done to get to the control board, but the battery disconnection happens at about 2:45 

 

Oh, don’t follow that one, they completely tear apart the wheel. So many unnecessary steps for just checking the battery voltages.

 Once you have the vertical sliding mechanism (the one with the handle) out, simply open up the mainboard cover. Nothing else to it.

 But definitely wait for the distributor’s comments before opening her up.

[mrelwood]

On 11/17/2021 at 8:05 PM, Buddywoof said:

Thanks for your feedback.  I guess I will need to learn how to take one of these apart.  I'm hoping battery replacement is not nearly as complex as a wheel or motor change!

btw - what voltage should battery 1 and battery 2 charge to after turning green and charger left on?

The voltage measurement calibration varies from unit to unit, so there isn’t a specific one that’s more “correct”. Mine used to go up to about 85.5V before calibration. But the left and right ones have always been within 0.1V on mine.

On 11/17/2021 at 4:47 PM, RagingGrandpa said:

That sounds like Battery 2 disconnected itself due to cell imbalance. That's worth investigating.

It is starting to look like that would be the case. Riding down to 90%, charging at least until green, and repeat a few times, should balance the cells and essentially fix the issue. But it won’t work if there is a permanent failure in one of the cell groups or one of the BMS.

[Buddywoof]

Thanks again for all your feedback.  I'm still waiting for the vendor to contact me on next steps.  Here are some other things I notice:

1)  When "Activated Status" on the battery is "disabled" (meaning wheel is on it's stand), I see up to 0.2 volt difference between Battery 1 and Battery 2.  But when "Activated Status" on the batteries are "enabled" (wheel is self balancing), then they balance out (exactly equal).

2) When charging, I always see battery 2 lagging behind battery 1 by 0.2 volts

3) and as mentioned in my previous post, when I left the charger connected after turning green, battery 1 is cycling between 84.2~84.7 volts whereas battery 2 cycles between 83.7~83.8 volts.  It seems like battery 1 wants to discharge and battery 2 wants to keep charging due to the imbalance.  Once I disconnect the charger, I get the behaviors of #1 and #2 above.

Too bad these units don't have individual battery cell monitoring.  That would make is so much easier to confirm if there is a bad cell.  I don't mind if the measurements are off but I do mind if I have a bad cell.

I do still feel like I have less range than my previous V11 and the voltage sag during riding seems higher.

Edited November 19, 2021 by Buddywoof

[Buddywoof]

On 11/17/2021 at 5:35 PM, Tawpie said:

There is always some possibility that the voltage measurement made by the wheel can be off, these things are notoriously imprecise. You want to open the wheel, disconnect both batteries, turn the wheel on to discharge the control board capacitors, then use a multimeter to CAREFULLY measure the battery voltage at their connector. They should be within 0.1V of each other, and within a tenth or two of 84V

I tried to measure the voltage on the batteries after a full charge but I think I need to get new multimeter.  Although my multimeter can measure up to 500 volts, for some reason, the readings don’t look right:

 

Left battery is measuring at 58.6 volts

Right battery is measuring at 59 volts

 

On the app, it shows:

Battery 1 =83.9 volts

Battery 2 = 83.7 volts

 

So before I go out and buy a new multimeter, I decided to switch the connections for the left and right batteries to see if the lower voltage follows the battery.  So I connected the right battery to the left connector and left battery to the right connector.  After this I checked the app and it shows:

Battery 1 = 83.7 volts

Battery 2 = 83.9 volts

 

So this seems to prove that one of the battery packs is indeed lower voltage and calibration seems ok.

 

What do you think? 

[RagingGrandpa]

1 minute ago, Buddywoof said:

I decided to switch the connections for the left and right batteries to see if the lower voltage follows the battery.

Great idea!

You've convinced me: there is a small ~300mV difference between the two packs, and this difference goes away when the EUC is being ridden (both packs online).

The wheel seems to work normally, and both packs charge above 83V. I vote 'continue normal use.'

If you really wanted to try to equalize them, try charging with only one pack connected, continuing 2hr after the charger light turns green. Note the app-reported voltage just before you disconnect the charger. Then swap packs and repeat.

[Buddywoof]

5 minutes ago, RagingGrandpa said:

Great idea!

You've convinced me: there is a small ~300mV difference between the two packs, and this difference goes away when the EUC is being ridden (both packs online).

The wheel seems to work normally, and both packs charge above 83V. I vote 'continue normal use.'

If you really wanted to try to equalize them, try charging with only one pack connected, continuing 2hr after the charger light turns green. Note the app-reported voltage just before you disconnect the charger. Then swap packs and repeat.

Great!  Thanks for your feedback.  I feel a bit more confident after reading your post!    I'm glad there are experienced folks here offering help.  I will try equalizing them by connecting just one battery pack at a time.  Thanks alot guys!  I'll report back with any additional info as I observe them.  

 

[mrelwood]

One thing we’ve seen in a few V11 units is that the communication lines of the batteries are swapped. So that the cable from the left battery goes to the right battery’s connector on the mainboard. This causes issues when the mainboard tries to balance between the two battery packs.

 If you have the control board cover open, definitely check the smaller white battery connectors as well!

[Buddywoof]

Thanks. Yes I also swapped the white cables too.   However, after doing this and putting it back together I noticed the wheel is tilted back by 4 degrees.  I then ran a "turning and forward correction" which fixed it but when the wheel is power cycled, it starts off with 1~2 degree forward tilt and I need to run  "turning and forward correction" every time to level it out.

At this point, I've asked if an exchange is possible.   This is just too many issues on a new wheel.   There other issue I have with this wheel is that it only logged my very first ride in the app "ride record" and stopped logging any rides after that. 

Edited November 20, 2021 by Buddywoof

[Paradox]

On 11/20/2021 at 10:58 AM, Buddywoof said:

At this point, I've asked if an exchange is possible. 

It's been a few months since the last post.  I was wonering what the outcome of this situation was?

[Buddywoof]

Hi,

I eventually got the wheel exchanged as the wheel cut out during my ride and crashed.  I believe it had something to do with the battery (must have been defective).  My replacement has been working without such issues but I haven't ridden it as much.  When I crashed, I tore my rotator cuff (which is a serious injury) and had surgery  (yes, I was fully armored in motorcycle gear yet still managed to tear my rotator cuff).  It's a long road to recovery from a rotator cuff surgery so it'll be a few months before I start riding regularly again.

[M640x]

On 11/15/2021 at 6:06 PM, Buddywoof said:

Hello, 

I have a new V11.  This is my 2nd one.  On this new one, after a full charge there is a relatively large difference between Battery 1 voltage and Battery 2 voltage.  As you can see in the screenshot, the difference between Battery 1 and 2 is up to 0.4 volts which I feel is significant.  I'm thinking these carefully balanced high quality cells from LG should have a very small delta (maybe 0.1 volts) given these are 20-cell packs (20 x 4.2 volts = 84 volts).  I suspect 1 of the 20 cells from Pack 2 is bad.

I'm wondering if other V11 owners are seeing such a delta between the two battery packs (battery 1 and battery 2)?  You can check this in the inMotion app-->settings-->About Vehicle-->Battery Pack Detail.  Thanks for your feedback.

Screenshot:

https://drive.google.com/file/d/1vxZh1qZjCyD8RnRDQz-1ECtBIOPKgqo4/view?usp=sharing

I had a large delta between my battery packs when I had a V11 that caused a cutout and fall at a very slow speed.  I had a batch 1 wheel and after removing the electronics cover on top I discovered that one of the battery packs had 0 volts while the other had "normal" voltage.  It was obviously faulty.  The wheel was sent back and replaced with another.