King Song S18 Discussion

[Tawpie]

10 hours ago, Fahrtwind said:

How do you charge your wheels?

In general, I keep an eye on it and unplug the charger 1-2 hours after it goes green. But I have starting using EUCWorld's connection to the HS110 smart plug to do the charger unplugging for me. I also noticed the vampire effect if you leave the charger plugged in overnight.

Of note, the eWheels fast charger I sometimes use will turn its output off when it believes charge is complete and that shuts the wheel down so there's no vampire. They tell me it balances etc., but for some reason I don't quite trust that it does so I finish charging with my slow factory charger (get to 80% on fast charger, then switch to slow—the total time to charge doesn't change because when it reaches 80% the current into the wheel is about 1.5A, same as the factory slow charger). Then again, I haven't done any careful observation to see exactly when it decides to remove power to the wheel... it might actually be just fine.

Edited February 12, 2022 by Tawpie

[Fahrtwind]

Thanks for your answers! My V5F is 6 years old now. Battery is still fine. I store the wheel with 50-70% SOC, and I leave it plugged in for some time after Charger turns green for passive balancing. I wanted to do the same with my new KS.  But the S18 behaves different…the light turns green once the current is below 300-400mA, but balancing still happens. Not sure why the S18 stopped charging, the BMS/Motherbord seems to behave different. 

[Tawpie]

1 minute ago, Fahrtwind said:

Not sure why the S18 stopped charging

They made charging changes to the firmware after (I think) 2.02... what firmware are you running? I'm on 2.12

 

Edited February 12, 2022 by Tawpie

[Fahrtwind]

Thanks. It is 2.09. KS Software tells me, it is the latest…

[The Brahan Seer]

On 2/12/2022 at 3:29 PM, Chriull said:

This could maybe only help joule counters showing battery capacity, which are not used in EUCs (just some ninebots?)

I was letting it drain to let the battery re-calibrate itself, from what you are saying the batteries aren't smart enough so its not required. Good to know, thank you!

[mrelwood]

 

On 2/12/2022 at 3:28 PM, The Brahan Seer said:

Once every 3-4 months

I balance charged my 16S once a week, and still the cells died prematurely. If I were you, I would study battery behavior and the EUC charging processes very closely before taking a risk of preventing almost all balance charging. KingSongs seem to be the worst in the area of balancing, possibly due to insufficiently low balancing currents.

 

On 2/12/2022 at 3:28 PM, The Brahan Seer said:

I personally don't like charging beyond the green light because excess charging causes extra strain on the batteries.

What balancing is is distributing the voltage from full cell groups to the ones that aren’t as full. So the full cells should never get overcharged even wheel left at the charger. There’s also the overvoltage protection on each BMS that stops all charging once any of the cell groups reach 4.25V or so. This can happen if the voltage balance is badly off, in which case the dying cells are the one killing the battery anyway, not overcharging. Bottom line, I don’t think there’s a practical reason to prevent balance charging while hoping to prevent excessive charging. Quite the opposite.

 

On 2/12/2022 at 3:28 PM, The Brahan Seer said:

I have documented the behaviour of my batteries so will know very quickly if something isn't quite right.  As long as everything is behaving as it should ie hitting 100% charge in the time frame required then additional 'battery balancing' is not required.

The potential issue is that you timing the charge is not nearly as precise as the great precision of BMS balancing. I hope you can catch things before they go haywire.

 

6 hours ago, The Brahan Seer said:

I was letting it drain to let the battery re-calibrate itself, from what you are saying the batteries aren't smart enough so its not required. Good to know, thank you!

@Chriull is right, there’s absolutely no reason to drain your batteries. Especially if you’re cautious of wearing the cells out. When an EUC shows the battery as 0%, The cells are still well within their regular operating range. And there is no component in an EUC that would benefit from an occasional low battery.

[The Brahan Seer]

@mrelwood I should have clarified I don't just take the time it takes to charge to 100% but also the range I experience from each charge. I would imagine if the battery starts to fail this will be seen with a lower range and sluggishness.  Any excessive charging will cause extra wear and tare on the battery. I understand how the battery balances itself from previous correspondence with you. Physically cells are very simple and not complicated but its the chemistry that causes the issues,   I just don't think cells suddenly fail often and if they do its due to excess wear and tare. I also won't use fast chargers for this reason. I appreciate what you are saying and understand the logic for doing so. I just don't think its required with a battery less than 2-3 years old.

[mrelwood]

On 2/14/2022 at 11:58 AM, The Brahan Seer said:

I just don't think its required with a battery less than 2-3 years old.

I hope everything goes well with your wheel. And it probably will, to be honest. Just a few reference points though:

- My 16S was less than 1 year of age when the first pack failed at 4000km.

- If you start feeling sluggishness while accelerating, a cell group has already failed beyond repair.

- I haven’t seen or heard about a single case where an EUC battery pack would’ve failed prematurely due to excessive charging. I’ve seen a few dozen that failed clearly due to insufficient balancing though.

[The Brahan Seer]

@mrelwood The 5-6 hour charge time for the S18 is ample for gross balancing (which is used for unbalanced cells)

 Balancing time= Battery Capacity expressed in amp hours divided by charger capacity in amps

= 13/2.5 = 5 hours. Which is when the green light comes on.

ref: https://www.ionenergy.co/resources/blogs/cell-balancing-battery-life/

I would look into why the batteries failed to give sufficient balancing rather than say its due to insufficient balancing. They don't fail to balance for no reason.

Edited February 16, 2022 by The Brahan Seer

[Chriull]

14 minutes ago, The Brahan Seer said:

Balancing time= Battery Capacity expressed in amp hours divided by charger capacity in amps

= 13/2.5 = 5 hours. Which is when the green light comes on.

Balancing time is not the whole charge time butonly the last charge percents, as also stated in your linked article under disadvantages of passive balancing: "They do not balance during the full SoC. They only balance through the top of each cell at around 95%. This is because if you have different cell capacities, you are forced to burn off the excess energy."

17 minutes ago, The Brahan Seer said:

They don't fail to balance for no reason

Passive balancing is very limited and it will fail over time by normal cell degradation.

Personally, i believe that very fast "whole battery degradation" as described by @mrelwood can happen by either discharging batteries quite fully and not charging full and by this balancing the battery. Imho, especially "earlier wheel" with low(er) capacity batteries (over)burdened the cells more, especially at low charge percentages.

Or otherwise by having bad luck and getting a pack with badly selected cells ...

[enaon]

on the s18, balancing starts only after the green light is on, gross balancing is not really related.

It is a bit complicated, but I think the advice to let it balance (keep it n the charges after the green light it on) for 5-6 hours every week or so, is on the safe side. 

 

Edited February 16, 2022 by enaon

[Miko.cz]

1 hour ago, mrelwood said:

- My 16S was less than 1 year of age when the first pack failed at 4000km.

My KS-16S 680Wh after 7500km (1.5y old), daily commuting all weather, sometimes longer trip. Charged by 95% supplied charger and 5% by quick charger (4A).
Voltage at the end of charging with balance = 67.7V, after about 7h disconnected lowers to 67.4V. EUCw batt resistance 0.13-0.19 Ohm.
Never left totaly depleted for longer time than hour. Sometimes (less than 5%) charged only to 80%. At least every 4-5th charging with balancing time.
My last trip few days ago was 38.5km (about 85kg total) EUC World said 506Wh used (about 7°C outside temp, EUCw ride record is here. During summer it was lets say about 15-20% better (as expected - temp and weight and 1200+-km less)
No special issues visible.
Sorry to be OT, hope this could help someone...

[Chriull]

3 minutes ago, enaon said:

on the s18, balancing starts only after the green light is on, gross balancing is not really related.

They still use "normal BMS" as in the wheels before? I can't remember any reports of some special new BMS for this wheel? Did i miss something?

[enaon]

14 minutes ago, Chriull said:

They still use "normal BMS" as in the wheels before? I can't remember any reports of some special new BMS for this wheel? Did i miss something?

I am not sure how it was before, I am not very sure how it is now to be honest, I have one here and the sub signal puzzles me, I was mainly saying that balancing is not active on this bms. 

 

[Chriull]

1 hour ago, enaon said:

I am not sure how it was before, I am not very sure how it is now to be honest, I have one here and the sub signal puzzles me, I was mainly saying that balancing is not active on this bms. 

 

Then it seems to be the normal balancing https://forum.electricunicycle.org/topic/22109-passive-balancing-a-simulation/#comment-359235 which happens in the CV stage and after the charger is unplugged after the green led.

Of course the current threshold of the green charger light has to be at some sane value.

Leaving the charger on after the green light shiuld not really help more. Maybe there are some tendencies once the cells in the pack are "bordeline" znbalanced and should be exchanged anyhow.

This passive top balancing has it's limits, the cells are quite heavily burdened by riding eucs and are consumables. Normaly this sytem wirks quite ok together. Thank KS that they have now like ninebot before cell voltages reported!

So no theories are needed anymore - one can see the state anytime!

 

[enaon]

1 hour ago, Chriull said:

Then it seems to be the normal balancing https://forum.electricunicycle.org/topic/22109-passive-balancing-a-simulation/#comment-359235 which happens in the CV stage and after the charger is unplugged after the green led.

Of course the current threshold of the green charger light has to be at some sane value.

Leaving the charger on after the green light shiuld not really help more. Maybe there are some tendencies once the cells in the pack are "bordeline" znbalanced and should be exchanged anyhow.

This passive top balancing has it's limits, the cells are quite heavily burdened by riding eucs and are consumables. Normaly this sytem wirks quite ok together. Thank KS that they have now like ninebot before cell voltages reported!

So no theories are needed anymore - one can see the state anytime!

 

on the packs I have here each bms has a series of leds, one for each cell, they are supposed to indicate the bleeding stage , I have not seen them light up while the charger led is red, but I will verify. 

 

 

aahh ok, I understand now what you are saying. I do not disagree, my comment was about balancing during the 5 hours of charging time The Brahan Seer talked about, but yes if bleeding stage is reached and few hours after removing the charger the total voltage is what it was supposed to be, all is ok. 

Edited February 17, 2022 by enaon

[Tawpie]

1 minute ago, enaon said:

on the packs I have here each bms has a series of leds, one for each cell, they are supposed to indicate the discharge stage of the balancing process

pictures? Wouldn't it be something if you could mod the battery case so these can be viewed? Then you'd know when they're done balancing... not that I expect it to change how I'd charge, but it'd be interesting!

[enaon]

2 hours ago, Chriull said:

So no theories are needed anymore - one can see the state anytime!

 

this is trully a nice development, maintenance will be so much easier now. 

 

this maybe will come with it's own set of problems, but it is the correct step.

While trying to find a nice 10s smart bms to replace the half ones on the s18 I stumbled on the xiaomi scooter bms, it is 10s, small, right amps, smart, perfect for the s18. But I found some videos talking about bms replacement, it turns out that many of the problems reported on xiomi scooters, are the bms misreporting cell level, not the cell level :)

So I abandoned the idea, and I hope ks has done a better job.   

Also, when I was looking for bms replacement for the z10, I found out that is is more than just reporting, if the protocol is not communicated the machine will not start. 

so I hope ks will not do this, or offer a bms as a replacement part.

But overall, I am excited about cell voltage reporting on the s20. 
 

Edited February 17, 2022 by enaon

[enaon]

56 minutes ago, Tawpie said:

pictures? Wouldn't it be something if you could mod the battery case so these can be viewed? Then you'd know when they're done balancing... not that I expect it to change how I'd charge, but it'd be interesting!

they are under the black side foam, running all the way down. 

you can see them here blinking, it is a video from a Russian user.

And one more thing I noticed just now, while upoading the video for you. His bms has an mcu on it, mine has not, very interesting  

https://streamable.com/t8e53z

Edited February 17, 2022 by enaon

[Chriull]

6 hours ago, Tawpie said:

pictures? Wouldn't it be something if you could mod the battery case so these can be viewed? Then you'd know when they're done balancing... not that I expect it to change how I'd charge, but it'd be interesting!

By such leds, showing active bleeding resistors one cannot see once balancing is done. They will light as long as the charger is attached (and some cells are unbalanced)  An important step for balancing is to disconnect the charger and led the cells with the little bit of overcharge discharge this little bit again.

[Fahrtwind]

Some updates. I´ve driven 120km on the S18 so far and really feel familar with it. I found some time for a closer look at the suspension. Without the damper (uninstalled), there was too much friction at the suspension fork, the wheel did not compress/decompress by gravity. So I decided to loosen the four screws holding the axle and the friction was gone completely! Then I started to tighten the screws step by step cross wise, checking the friction regulary. I think, now the suspension works as it should, the whole procedure was done in 30 minutes - the improvement is huge!

Another thing that attract my attention: the board temperature shows always 15°C. (KS App and Darknessbot) Even if the enviroment is 20°C...and while using the wheel, it does rise by 2 -3 degrees only... Is this something I have to be worried about?

Thanks

Manuel

[Tawpie]

8 hours ago, Fahrtwind said:

Another thing that attract my attention: the board temperature shows always 15°C. (KS App and Darknessbot) Even if the enviroment is 20°C...and while using the wheel, it does rise by 2 -3 degrees only... Is this something I have to be worried about?

I wouldn't worry too much about it, if the wheel is under warranty I'd let your reseller know so that you have a record that it happened before the warranty ran out. But the motors basically never overheat, so the measurement isn't "necessary".

[Fahrtwind]

Ok, I thought it is the board temperature...and I already had a temperature warning on my V8F after driving a very steep hill in summertime. The wheel asked me for cool down, pedals were tilted.

I will have a look how the wheel behaves in Summer. Maybe it is just a kind of an offset... Thanks

Edited March 1, 2022 by Fahrtwind

[Tawpie]

Just now, Fahrtwind said:

I thought it is the board temperature...and I already had a temperature warning on my V8F after driving a very steep hill in summertime.

krap, I need more coffee. Board temperature is very important. S18s are generally cool running and don't have a history of overheating so it's probably not critical? But since it does seem to move with use, I'd treat it as you suggest: pretend it has an offset.

[dycus]

 

I wrapped my S18 with pink and green fluorescent vinyl, on bright sunny days it truly stabs you in the eyeballs. My camera can't capture just how vibrant the color is!

Each panel got a base wrap of green vinyl. I designed the pink graphics in Illustrator, cut them out on a vinyl cutter, and used transfer tape to apply them to the panel. Then every panel got a protective clear wrap over it. Four panels wrapped three times each means this ended up taking several days from start to finish. It's certainly not perfect but the imperfections are pretty minor, things like little air bubbles and a wrinkle or two in some spots. But overall, I'm very satisfied with how it turned out!

I ride on trails so I knew the wrap would get wrecked immediately if I didn't put the protective film on it. I took these pictures after some riding (and falling) because I think it's important to show how the wrapping process holds up to abuse.
There are some gouges where it slid over some particularly large rocks, but when it just slides in the dirt, the clear vinyl actually protects it very well. There are scratches visible on it but it doesn't rip easily. Certainly, without it, the edges of the pink vinyl would catch much more and get ripped up.
Eventually I will patch the gouges by trimming off the ripped vinyl, cleaning it, and putting a small piece of the clear over it.

The upper power pads are by Mono Customize. Lower pads are the KaiPads V2 by Kai Sherman. The shock is DNM RCP2S, 550lbs, 200mmx56mm.
The protective film is Armor Up 8mil polyurethane wrap. Pricey, but it really seems worth the money so far.
https://www.amazon.com/dp/B09DG56M4K

Edited March 28, 2022 by dycus