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My 14-C has died.....what went wrong!?


fourthewin

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To jog the cells, I ran my 14C down to about 10% battery life on saturday night. When I got home, I put it away (I don't like to charge when I go to sleep). 

The next day, I noticed that it wouldn't turn on. So I put it on the charger. First thing I noticed was that the charging light didn't come on. So I disconnected it, and tested the power. 

First I checked the cord plugged into the wall:120v. Then the plug that goes into the EUC: 67v. I then popped the lid on it and tested the opposite side of the charging port: 60v. I then disconnected the charger and checked both fuse links, they're good. I then pulled the XT60 plug apart and tested that: 1.5v?! That seemed weird. So I was thinking maybe I ran it down too far. 

I put it back on the charger and let it go for 8hrs. When I came back, still no light. So I checked the battery power again. This time it was 18v. 

I connected the XT60 again and tried to turn it on. It did, but only the headlights. The front and back light was flashing and alternating. The bluetooth light was also blinking blue. 

I put it back on the charger and let it run all night, next morning still no light on the charger but now the battery reads 22v. 

Notes: The charger when disconnected from the Uni turns green, when connected, there is NO light. Thinking it might be the charger, I replaced the charger with an airwheel charger with the same specs except for .5 less amps. Same thing, green light when disconnected, nothing when connected. 

What's going on guys!? Are my batteries toast? 

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@fourthewin: i assume the xt60 is at the discharge side between the battery and the mainboard? 1.8v for 16 cells in series should mean quite dead batteries. Also the 18-22v. I would have assumed that the bms shut off the output due to cell undervoltage and the voltages you measured are from a voltage divider between the "closed" mosfets and your voltmeter - but since the headlights were "working" this could not be the case...

either the/some/most cells were/are completely down (liion cells cannot really be jogged...) or you have some bms malfunction... 

if sou feel confident to do so you could open your battery pack and measure all the cell voltages - just be carefull to short absolutely nothing! 

For some reading about liion clls batteryuniversity.com is a great place!

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12 minutes ago, fourthewin said:

I guess the next step is, how to get the warranty? It has a year and I bought it new from www.electricunicyclereviews.com

Who do I contact in the US? 

Don't know how it is in the US - here in europe the warranty on the batteries is normally less tha a year... :(

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16 minutes ago, fourthewin said:

I guess the next step is, how to get the warranty? It has a year and I bought it new from www.electricunicyclereviews.com

Who do I contact in the US? 

They went out of business and the 14C is no longer manufactured and to the best of my knowledge, supported.

EWheels still sells parts, including new battery packs for the 14C.

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1 hour ago, fourthewin said:

To jog the cells, I ran my 14C down to about 10% battery life on saturday night. When I got home, I put it away (I don't like to charge when I go to sleep). 

Whilst it is VERY sound advice to not leave a wheel charging all night indoors, It is never a good idea to leave a battery in the discharged state, especially on the later 800W KS-14C's which had a much lower low voltage cut off. It only takes one or two cells to be of significantly lower capacity, which can come simply from not leaving the charger on long enough after it shows fully charged for the pack to fully balance or might just be some cells aging faster than others. Once cells have been left at less then 3V for a time they will permanently damage. Even 15 minutes charge while you were preparing for bed would probably have made the difference.

@KaleOsaurusRexwas the owner of electric unicycle reviews and shut up shop a month or so ago.

As suggested above, everything does point to the fault being with the battery. What capacity is your KS-14, if it has two parallel batteries one may be OK?

Failing that, if the battery is out of warrantee replacing it or changing out the damaged cells (carefully) yourself are the only options, however replacing some cells can often be a waste of time unless all except a couple of cells seem fine.

Edit: just spotted you said: "to jog the cells", so you had some sort of problem with them before? As you have found out, nothing good ever comes out of deliberately cycling Lithium Ion cells, it just ages them.

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It's a 680whr cycle. 

I spoke to Will the owner and he's offered his help. He said he's heard of other people have a similar problem and was able to fix it fairly easily. However, I don't know what that process is. Does anyone have any ideas?

I purchased in April of 2017. What is the warranty on these batteries? Less than 6 months. 

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1 hour ago, fourthewin said:

It's a 680whr cycle. 

I spoke to Will the owner and he's offered his help. He said he's heard of other people have a similar problem and was able to fix it fairly easily. However, I don't know what that process is. Does anyone have any ideas?

I purchased in April of 2017. What is the warranty on these batteries? Less than 6 months. 

If you're already talking to Will I'm sure he'll be able to explain the process.

The warranties on any of our wheels is only as good as the warranty offered by the dealers, since it's essentially impossible for us to interact with the manufacturers directly. I think the manufacturers ignore anyone outside of China. Maybe inside China too :(

Ewheels specifically warranties their KingSong wheel batteries for one year from purchase. Your warranty will depend on electricunicyclereviews

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1 hour ago, fourthewin said:

It's a 680whr cycle. 

I spoke to Will the owner and he's offered his help. He said he's heard of other people have a similar problem and was able to fix it fairly easily. However, I don't know what that process is. Does anyone have any ideas?

I purchased in April of 2017. What is the warranty on these batteries? Less than 6 months. 

   A guy with a boosted board let the batteries get too low to start a charge, so his friend pulled him behind his car and regeneration charged the batteries enough to let the charger finish the charge.  Maybe holding it on a powered treadmill at high speed?

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52 minutes ago, steve454 said:

   A guy with a boosted board let the batteries get too low to start a charge, so his friend pulled him behind his car and regeneration charged the batteries enough to let the charger finish the charge.  Maybe holding it on a powered treadmill at high speed?

This might work, as might any other way way of getting 50-60V across the battery and it certainly is worth considering. Anything less than 50 volts won't work at all as the lowest the cells can be allowed to go is 3V/cell - 48V for the pack. Possibly even leaving the charger plugged in for a whole day (but not unattended just in case!) However every time I've heard of this being done successfully it has been Lithium Iron (LiFePO4) batteries, not Lithium Ion. LiFe cells are almost completely undamaged by over discharge yet their chargers and/or BMS commonly prevent them being charged again (Segways for example).

I use 2 cell LiFe batteries as model radio control receiver batteries as their 6.6V is the same as a 5 cell NiMH battery. Due to their high self discharge I have a couple of times flattened them all the way to zero. Telling my charger it is a NiMh and monitoring it carefully has recovered them completely and I'm still using the same batteries several years later.

Trying the same thing with LiIon, has worked but the batteries have never been quite the same again with noticeably higher internal resistance.

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1 minute ago, fourthewin said:

Is there ANYWAY to reset the BMS or force charge the batteries? 

What about 12v trickle charger? Is there any danger to trying it? 

I suppose there's no danger, but 12 volts won't accomplish anything. You would need a 67 volt trickle charger.  Note that a trickle charger works by limiting the current, not the voltage.

Didn't you say that Will agreed to help you :confused1:

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10 minutes ago, fourthewin said:

Is there ANYWAY to reset the BMS or force charge the batteries? 

What about 12v trickle charger? Is there any danger to trying it? 

It might be easiest to ship it to Ewheels on your dime, let them diagnose it, and give an estimate of the cost to repair.  You would be out about $40 bucks to ship it one way.  It may need a battery and a board.  But first go to the Ewheels website and either do a live chat, or email them with the problem, maybe they can tell you if it is possible to reset the BMS.

It sucks that your wheel has died, maybe give it a few days and someone will have a solution,  I don't think the BMS will let you force charge the batteries.  I am thinking that one or more cells may be bad, and that is why it won't charge.  Hopefully all you need is a new battery.  And I hope you can get it fixed under warranty.

Someone posted a week or two ago about draining the battery on his wheel to 10% and recharging and got more range.  I at first thought that was a good idea, but then @Keith reminded us that doing that would possibly expose a bad battery, if one of them dropped lower than the rest of the batteries, the BMS would not allow charging.:o  So I gave up that idea, and continue doing what I have been doing, only riding to about 50% battery, then recharging.  Then again, I've read of a few riders that ride frequently down to low voltage and charge at the coffee shop and ride another 10-15 miles that day.  So, unsure, but anyway, hope you get it running again.

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3 minutes ago, steve454 said:

It might be easiest to ship it to Ewheels on your dime, let them diagnose it, and give an estimate of the cost to repair.  You would be out about $40 bucks to ship it one way.  It may need a battery and a board.  But first go to the Ewheels website and either do a live chat, or email them with the problem, maybe they can tell you if it is possible to reset the BMS.

It sucks that your wheel has died, maybe give it a few days and someone will have a solution,  I don't think the BMS will let you force charge the batteries.  I am thinking that one or more cells may be bad, and that is why it won't charge.  Hopefully all you need is a new battery.  And I hope you can get it fixed under warranty.

Someone posted a week or two ago about draining the battery on his wheel to 10% and recharging and got more range.  I at first thought that was a good idea, but then @Keith reminded us that doing that would possibly expose a bad battery, if one of them dropped lower than the rest of the batteries, the BMS would not allow charging.:o  So I gave up that idea, and continue doing what I have been doing, only riding to about 50% battery, then recharging.  Then again, I've read of a few riders that ride frequently down to low voltage and charge at the coffee shop and ride another 10-15 miles that day.  So, unsure, but anyway, hope you get it running again.

I'd barely be able to ride my wheels if I limited myself to 50% battery range :(

Maybe I'm playing a game of Russian Roulette, but I regularly ride my wheels down to 25%, and periodically to 10% - 15%. No problems so far - knock on wood.

I suppose you could avoid dropping to 10%, but I think 50% is being unnecessarily conservative. Probably 20% is a good middle ground for those concerned.

I'm probably an outlier in this regards, but my view is to enjoy the wheels. Use them. Don't let the pursuit of extended lifetimes limit the enjoyment of the wheel.

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2 hours ago, steve454 said:

   A guy with a boosted board let the batteries get too low to start a charge, so his friend pulled him behind his car and regeneration charged the batteries enough to let the charger finish the charge.  Maybe holding it on a powered treadmill at high speed?

 

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8 minutes ago, Hunka Hunka Burning Love said:

I remember seeing someone recovering a Solowheel battery that wasn't charging.  I think they rolled the wheel somehow to boost up the voltage so it tricked the BMS to work again?  Here's one video I found - don't know if it might work.

 

Brilliant!

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1 hour ago, Hunka Hunka Burning Love said:

I remember seeing someone recovering a Solowheel battery that wasn't charging.  I think they rolled the wheel somehow to boost up the voltage so it tricked the BMS to work again?  Here's one video I found - don't know if it might work.

 

Hopefully I'll never need it, but I'm going to remember this video for future reference.:thumbup:

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There was one more video demonstrating how to boost a dead Solowheel.  I can't seem to find it.  Maybe @esaj knows where it is.  IIRC the guy had the charger connected and basically spun the wheel on the ground to get it spinning to help increase the voltage level up I think.

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7 hours ago, ir_fuel said:

 

In this video (1) he revived lifepo cells and not lion - as @Keith mentioned they have a different chemistry and behaviour as our liion. Also the the videos of recovering solowheels could regard the old ones with lifepo cells?

at http://batteryuniversity.com/learn/article/low_voltage_cut_off they state the liion cells (could) have a over discharge protection inside which can be disabled again. But they also warn "Do not boost lithium-based batteries back to life that have dwelled below 1.5V/cell for a week or longer. Copper shunts may have formed inside the cells that can lead to a partial or total electrical short. When recharging, such a cell might become unstable, causing excessive heat or show other anomalies"

i would "translate" excessive heat with danger of fire...

so whatever you try @fourthewin- don't leave your battery pack unattended!

7 hours ago, Marty Backe said:

...

I'm playing a game of Russian Roulette, but I regularly ride my wheels down to 25%, and periodically to 10% - 15%. No problems so far - knock on wood.

I suppose you could avoid dropping to 10%, but I think 50% is being unnecessarily conservative. Probably 20% is a good middle ground for those concerned.

I won't consider this as russian roulette - the percentage the app/wheel shows is not the "real" charge percentage - there should be enough additional "reserves".

just if the cell balancing by the bms does not work correctly or the cells are already quite aged, the chance of the weakest cell "dying/getting undervoltage/shutting off" rises the lower one discharges the pack... (2)

Quote

I'm probably an outlier in this regards, but my view is to enjoy the wheels. Use them. Don't let the pursuit of extended lifetimes limit the enjoyment of the wheel.

+1

especially riding a wheel down to 10% and leaving it for one night/day does not inflict any problems! There must have been some other prob already.

did not some ks14 measure "wrong" voltages, so the wheels shut of way to early while regenerative braking? - maybe this could also inflict "low" battery state somehow and be "reset", if one knows how... or just some way for their bms to be reset...

looking forward to @fourthewin's report on how this will be resolved by Will!

(1) this is a "bad" video anyhow - he shows many stupid things and has no idea of what he's doing.

(2) @zlymex posted imho once a ?constant current source" to effectively balance the cells - such a thing should make more sense than driving the wheel "more conservatively"

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7 hours ago, steve454 said:

That's the one I was remembering, @Sven posted it I think.

 

6 hours ago, Hunka Hunka Burning Love said:

I remember seeing someone recovering a Solowheel battery that wasn't charging.  I think they rolled the wheel somehow to boost up the voltage so it tricked the BMS to work again?  Here's one video I found - don't know if it might work.

All you are showing is what I have already I said above, I have only seen this work with LiFe, both that boosted board and that Solowheel have Lithium Iron batteries.

indeed, in the thread discussing that boosted board I said that adding an 18650 pack to his existing LiFe pack was a very dumb thing to do.

Surely if @fourthewin has a 680Wh Kingsong he has got two 340Wh packs, one in either side of his wheel, I find it surprising that both would have failed?

Sticking a 12 Volt trickle charger on a 67V battery is completely pointless and downright dangerous, it is unlikely that the every cell is down to well below 3V as that would have taken forgetting to turn the wheel off and leaving it leaning trying to balance all night. So potentially you are suggesting sticking a 12V charger on to a battery that has one or two damaged cells and possibly well in excess of 50 Volts  floating around, if the damaged cells did improve the 12V charger might not be well enough reverse protected to stop a massive charge going back through it.

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7 hours ago, Marty Backe said:

I'm probably an outlier in this regards, but my view is to enjoy the wheels. Use them. Don't let the pursuit of extended lifetimes limit the enjoyment of the wheel.

Marty is absolutely right and as @Chriull has said above 10% isn't usually 10%, most wheels will have a quite conservative low voltage alarm so 10% is often more like 30% in reality. Some like the IPS wheels monitor individual cell voltages and alarm on the lowest cell - it is a great pity more do not do that.

However there is a huge difference in driving down to 10% because you are on a long ride and deliberately running the wheel down because you have heard a dumb rumour that it will improve the battery. Do not also forget that it is a low voltage alarm, if the wheel is ridden very slowly or left on to flatten itself you will pull the battery down way way lower than if it is ridden normally down to 10%.

However I do know that later KS-14C's had their low voltage cut off lowered right down to (I think it might have been 48V?) On mine it is 55 volts so my range is terrible, and I know I can safely flatten it to 0% as that is still 55V on the pack.

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12 hours ago, fourthewin said:

It's a 680whr cycle. 

I spoke to Will the owner and he's offered his help. He said he's heard of other people have a similar problem and was able to fix it fairly easily. However, I don't know what that process is. Does anyone have any ideas?

I purchased in April of 2017. What is the warranty on these batteries? Less than 6 months. 

Thing is, that a 14C from unicyclereciews can be from middle of 2016, as at this time (afaik) he ordered those wheels. So perhaps the Long Standing has done some damage to the cells?

 

8 hours ago, Marty Backe said:

Maybe I'm playing a game of Russian Roulette, but I regularly ride my wheels down to 25%, and periodically to 10% - 15%. No problems so far - knock on wood.

I suppose you could avoid dropping to 10%, but I think 50% is being unnecessarily conservative. Probably 20% is a good middle ground for those concerned.

Nothing wrong on this...perfect behaviour!

 

1 hour ago, Keith said:

Surely if @fourthewin has a 680Wh Kingsong he has got two 340Wh packs, one in either side of his wheel, I find it surprising that both would have failed?

As they are daisy chained in a KS14 and fourthewin only posted ONE measurement, perhaps only one is defect....i would guess the one near the board then.

Perhaps the first after charging is working good but as the BMS of the last protects to Switch together. a low voltage and a normal voltage.

I would measure both packs seperatly....

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