King Song S18 Discussion

[kiitick]

Got it unlocked. Rode it fairly hard. Average 20 mph, topped at 30. My highest draw was 60 amps. Riding 25 up a steep hill in my neighborhood. I made it 15 miles and it was down to 40 percent while riding. But came back up to 55 percent after I stopped.  I figured if I could get 18 miles, that would be excellent for my 105 kilos. 

It for sure had more oomph to it than stock, and I didn't notice any deterioration in performance, as I was able to accelerate up my test hill both at the beginning of the ride and right at the end.  I think the extra for the upgraded battery turns a good wheel into a fantastic short distance or technical wheel. I would not like it to be my only one, range anxiety being a thing, but it's perfect for my usage scenario, which is riding trails.

[dycus]

I've been working on a tether backpack battery for my S18 for the past 2 weeks, and I just finished the first test run today!

I'm using stock S18 battery packs in the backpack. They're a convenient shape, have a built-in BMS, and are in a sturdy enclosure. They can be directly paralleled with the existing S18 packs. Currently the tether supports one pack but it will support up to 3 in the future. The backpack battery sees much less current than stock (worse case about half current with 3 packs) so I have no problem using the higher-capacity stock cells.

Technical details:
- This is a "vamp and ride" (VnR) system, meaning it is a direct parallel connection to the existing batteries. It is not a charge-and-ride system like Kingsong tried with the KS-Power.
- I designed the connector to safely disconnect when I drop the wheel. It attaches with magnets and the electrical connection is made with high-current pogo pins.
- I tested the connector at 15A for 10 minutes and the pogo pin temperature only rose 13C. If I had all three batteries in the backpack, a 15A draw from them would equate to 27A total wheel current (~2kW). With fewer batteries, the current goes down. If I'm pulling 2kW for 10 minutes straight, my connector is the last thing I'd be worried about!
- The tether wiring+pogo pin resistance is only ~11 mOhm.
- The wheel and the battery pack must be within a couple volts of each other before connecting to prevent high currents from flowing. In practice this just means ride/charge the wheel until they're the same voltage, then connect it and charge them together.
- The connector covers are spring-loaded so they automatically snap shut as soon as the tether disconnects. This helps protect the pogo pins and also prevents shorting the batteries.
- The wiring in the wheel is fused with two 10A fuses and the three packs will be fused at 6.3A each.

I went on a 2h45m ride today with my Molicel S18 (900Wh) and a single S18 pack in my backpack (360Wh), for a total 1260Wh capacity. I went 37.3mi, ending at 64.6V and 8% battery. I averaged 34.3 Wh/mi. I was accelerating hard and riding at high speed (~25mph) constantly.
This is consistent with the previous range test I did without the extra pack, where I went 24.8mi with an average consumption of 33.7 Wh/mi. The single extra pack adds 40% more capacity and today I went 50% further, so that about tracks. I wonder if the extra parallel pack helped efficiency more than expected, or if that's just within the noise.

Have a bunch of build photos!

Edited May 27, 2022 by dycus

[fbhb]

35 minutes ago, dycus said:

I've been working on a tether backpack battery for my S18 for the past 2 weeks, and I just finished the first test run today!

This is a fantastic project you've executed here, very well done and I for one will definitely be looking forward to hearing further reports on your progress.

Edited May 27, 2022 by fbhb

[enaon]

Very nice work,  why are you using the signal wires? I think it is best to leave them unconnected. if they are connected and a fault happens to the front pack, the charging will not stop. You can connect the power in vamp mode, but not the safety signal. 

Edited May 27, 2022 by enaon

[Ksmack]

1 hour ago, dycus said:

I've been working on a tether backpack battery for my S18 for the past 2 weeks, and I just finished the first test run today!

I'm using stock S18 battery packs in the backpack. They're a convenient shape, have a built-in BMS, and are in a sturdy enclosure. They can be directly paralleled with the existing S18 packs. Currently the tether supports one pack but it will support up to 3 in the future. The backpack battery sees much less current than stock (worse case about half current with 3 packs) so I have no problem using the higher-capacity stock cells.

Technical details:
- This is a "vamp and ride" (VnR) system, meaning it is a direct parallel connection to the existing batteries. It is not a charge-and-ride system like Kingsong tried with the KS-Power.
- I designed the connector to safely disconnect when I drop the wheel. It attaches with magnets and the electrical connection is made with high-current pogo pins.
- I tested the connector at 15A for 10 minutes and the pogo pin temperature only rose 13C. If I had all three batteries in the backpack, a 15A draw from them would equate to 27A total wheel current (~2kW). With fewer batteries, the current goes down. If I'm pulling 2kW for 10 minutes straight, my connector is the last thing I'd be worried about!
- The tether wiring+pogo pin resistance is only ~11 mOhm.
- The wheel and the battery pack must be within a couple volts of each other before connecting to prevent high currents from flowing. In practice this just means ride/charge the wheel until they're the same voltage, then connect it and charge them together.
- The connector covers are spring-loaded so they automatically snap shut as soon as the tether disconnects. This helps protect the pogo pins and also prevents shorting the batteries.
- The wiring in the wheel is fused with two 10A fuses and the three packs will be fused at 6.3A each.

I went on a 2h45m ride today with my Molicel S18 (900Wh) and a single S18 pack in my backpack (360Wh), for a total 1260Wh capacity. I went 37.3mi, ending at 64.6V and 8% battery. I averaged 34.3 Wh/mi. I was accelerating hard and riding at high speed (~25mph) constantly.
This is consistent with the previous range test I did without the extra pack, where I went 24.8mi with an average consumption of 33.7 Wh/mi. The single extra pack adds 40% more capacity and today I went 50% further, so that about tracks. I wonder if the extra parallel pack helped efficiency more than expected, or if that's just within the noise.

Have a bunch of build photos!

Wow! This is amazing. 

[dycus]

Thanks for the kind words!

 

1 hour ago, enaon said:

Very nice work,  why are you using the signal wires? I think it is best to leave them unconnected. if they are connected and a fault happens to the front pack, the charging will not stop. You can connect the power in vamp mode, but not the safety signal. 

Are you sure? Do you have more information on that? I did some probing and saw continuity between all the same-type signal pins. That is, the blue wires on all three packs are connected, and likewise all the green ones are connected. This leads me to believe they are probably using some kind of simple open-drain flagging system. I would assume that if the signal wires of 3 packs can be connected, then more can as well.

My hope is that this would let the backpack batteries signal the S18 in case one of the packs has an issue.

[enaon]

19 minutes ago, dycus said:

Thanks for the kind words!

 

Are you sure? Do you have more information on that? I did some probing and saw continuity between all the same-type signal pins. That is, the blue wires on all three packs are connected, and likewise all the green ones are connected. This leads me to believe they are probably using some kind of simple open-drain flagging system. I would assume that if the signal wires of 3 packs can be connected, then more can as well.

My hope is that this would let the backpack batteries signal the S18 in case one of the packs has an issue.

I have no real info on them, but have noticed that there is a margin of  ~12-19 volts on the sub signal that means healthy(not the same on all packs for the same charge state), bellow 12 they stop the charge, I think you will not allow the voltage to drop if you parallel them. (green is the sub signal  on the back right pack)

Edited May 27, 2022 by enaon

[dycus]

34 minutes ago, enaon said:

I have no real info on them, but have noticed that there is a margin of  ~12-19 volts on the sub signal that means healthy(not the same on all packs for the same charge state), bellow 12 they stop the charge, I think you will not allow the voltage to drop if you parallel them. (green is the sub signal  on the back right pack)

Interesting, thank you. I did notice the green wires output ~12V on each pack, but when they were all in the wheel the green line was at 13.5V.

Do you know what the behavior is of a faulty pack? Does the signal go to a couple volts or less? If it is open drain, it should be able to pull the signal to ground pretty strongly.

[enaon]

3 minutes ago, dycus said:

Do you know what the behavior is of a faulty pack? Does the signal go to a couple volts or less? If it is open drain, it should be able to pull the signal to ground pretty strongly.

I have seen a front pack stopping the charge at ~90 percent by having it's signal to ~11 volts, so I think they are not a simple on/off logic level. 

[enaon]

5 minutes ago, dycus said:

Interesting, thank you. I did notice the green wires output ~12V on each pack, but when they were all in the wheel the green line was at 13.5V.

 

this could be because the back packs have a higher voltage on the signal than the front ones. 

[dycus]

Maybe I'll have the backpack signal wires disconnected from the wheel but monitor them by other means. I definitely want to keep the safety features of the built-in BMS.

[Tawpie]

Let me know when you've got your kit for sale! If I still have my S18 I might bite. Great project, so well thought out and executed.

[EUC Custom Power-Pads]

Today I got a new S18 with production date 02/2022 and wonder why the DNM shock AOY-36RC is still or already again installed. As far as I can remember, this was replaced by the AO-38RL? 

[Ksmack]

1 hour ago, EUC Custom Power-Pads said:

Today I got a new S18 with production date 02/2022 and wonder why the DNM shock AOY-36RC is still or already again installed. As far as I can remember, this was replaced by the AO-38RL? 

I got a new s18 two weeks ago and it also came with the 36RC. 

[dycus]

I went on Marty's Mt. Wilson ride yesterday, it was awesome! I brought the extra 360Wh pack because I knew there was no way I would make it otherwise.

I don't have an exact mileage because I had to stop the EUC World tour recording early (my phone was just about dead), but that plus some measurements on Google Maps puts me at about 37 GPS miles. About 4500ft of elevation between the min and max points we were at.
The wheel reported 38.9mi. At the end I still had 25% battery, at 68V. The last portion of the ride was all downhill, so I gained several % at that point, then used it up getting back to the cars.

Everybody loved the tether, and it worked great!

Edited May 31, 2022 by dycus

[RetroThruster]

I might have missed something but my SE version is showing 75% charged and 78 volts via EUC World app but my 5a charger shows 84 volts when it shuts off, the stock charger also stops charging at the same voltage as the fast charger, only EUC World is showing the lower charge/voltage.  Am I missing something here?

[Funky]

5 minutes ago, RetroThruster said:

I might have missed something but my SE version is showing 75% charged and 78 volts via EUC World app but my 5a charger shows 84 volts when it shuts off, the stock charger also stops charging at the same voltage as the fast charger, only EUC World is showing the lower charge/voltage.  Am I missing something here?

How much Volts shows kingsong app by chance? Have you tried leaving "original" charger connected for longer time 30min -1hr? Even if it's green, it still charges..

If nothing changes - you may have bad news. (Ofc if both charged suddenly aren't busted..)

Edited May 31, 2022 by Funky

[enaon]

1 hour ago, RetroThruster said:

I might have missed something but my SE version is showing 75% charged and 78 volts via EUC World app but my 5a charger shows 84 volts when it shuts off, the stock charger also stops charging at the same voltage as the fast charger, only EUC World is showing the lower charge/voltage.  Am I missing something here?

how can you tell the voltage the stock charger stops at?

it looks like you either have a bad motherboard, or a bad bms. 
 

[enaon]

5 hours ago, EUC Custom Power-Pads said:

Today I got a new S18 with production date 02/2022 and wonder why the DNM shock AOY-36RC is still or already again installed. As far as I can remember, this was replaced by the AO-38RL? 

they use the original shock since late last year. They also stopped cutting off the bottom part of  the sliders, pedal height adjustment is possible again. They also improved their finishing a bit. 

Edited May 31, 2022 by enaon

[RetroThruster]

47 minutes ago, enaon said:

how can you tell the voltage the stock charger stops at?

it looks like you either have a bad motherboard, or a bad bms. 
 

You obviously can't but it doesn't charge any further than the 5a charger.  I guess I could charge next time with the stock charger and then try the 5a charger to see what voltage it's reading.  So you're saying that EUC World is reporting state of charge more accurately than the 5a fast charger (showing 84v)?

Edited May 31, 2022 by RetroThruster

[enaon]

22 minutes ago, RetroThruster said:

You obviously can't but it doesn't charge any further than the 5a charger.  I guess I could charge next time with the stock charger and then try the 5a charger to see what voltage it's reading.  So you're saying that EUC World is reporting state of charge more accurately than the 5a fast charger (showing 84v)?

euc world reports what the motherboard reports, unless the motherboard has the voltmeter circuit broken, this is a case of a bms signaling early end of charge. Better not to use/charge the wheel tlll you make sure, maybe by measuring the voltage on one of the front batteries with a voltmeter. 

 

Edited June 1, 2022 by enaon

[RetroThruster]

19 hours ago, enaon said:

euc world reports what the motherboard reports, unless the motherboard has the voltmeter circuit broken, this is a case of a bms signaling early end of charge. Better not to use/charge the wheel tlll you make sure, maybe by measuring the voltage on one of the front batteries with a voltmeter. 

 

Very good, I really appreciate your help!!

[ijeff]

Just another Molicel S18 owner here, as my first wheel. It has been about a month now, with over 850 km on the odometer thus far. It has been running great and getting an estimated 70km on a charge, which isn't great by EUC standards but excellent coming from a Onewheel XR. Haven't noticed any issues with voltage sag other than one false start while around 30% charge (did my usual start but pedals dipped a bit given road surface and lean).

I really wish KS gave us the option to customize the riding modes like on the Onewheel or VESC controllers. It would be nice to see continued firmware support for the S18.

On 5/31/2022 at 5:38 PM, RetroThruster said:

I might have missed something but my SE version is showing 75% charged and 78 volts via EUC World app but my 5a charger shows 84 volts when it shuts off, the stock charger also stops charging at the same voltage as the fast charger, only EUC World is showing the lower charge/voltage.  Am I missing something here?

How long are you leaving EUC World open? I need to wait a bit after opening the app for it to read the actual state of charge.

[Gewglymewgly]

Does anyone know anything about how to get in touch with kingsong? I have an s18 which had charging port issues in the way of it becoming brittle and breaking off. I have been trying to reach out to someone to help me the scooter is less than. A year old and has under 1000 mi on it. 

[Tawpie]

29 minutes ago, Gewglymewgly said:

Does anyone know anything about how to get in touch with kingsong? I have an s18 which had charging port issues in the way of it becoming brittle and breaking off. I have been trying to reach out to someone to help me the scooter is less than. A year old and has under 1000 mi on it. 

Your best course of action is to call your local reseller—or eWheels or RevRides online. They usually stock parts or can get them, and sell more than just EUCs.