Kingsong S20/S22 (Confirmed)

[meepmeepmayer]

33 minutes ago, Rollin-on-1 said:

But I have seen several comments that since voltage sag isn't as big of a problem, the actual range could be similar for a Master with 2400wh Samsung 50E or Samsung 40T.  Not sure if this will be true, but hopefully this comparison holds for the KS22 with Samsung 40T vs LGM50LTs as well.

You're right. Computing capacities might no longer work for these quite different kinds of cells. We need real world range tests and comparisons.

7 minutes ago, fryman said:

+1 How will this make the wheel safer?  I would not want to loose anymore range.

The 40T cells have super high discharge and in general should cope better with very high stresses. So overleaning at anything but top speed is much less likely. Not that it really was a problem with the regular cells. But I guess if you like steep hills, this sounds good.

[chanman]

Doesn't matter if you can draw 100A from the cells safely if it fries the MOSFETs or motor. I'm not convinced there was enough margin on the existing board to justify this, but obviously the electrical engineers at kingsong would be more qualified to answer.

[FunTech4Real]

40T is better for so many reasons... I've explained it too many times in too many different places and don't have time to compile it right now. But know this: You likely won't get any less useable range out of the high discharge 40T cells vs the high capacity LG M50T/LT cells. 

[Chriull]

6 minutes ago, chanman said:

Doesn't matter if you can draw 100A from the cells safely if it fries the MOSFETs or motor.

The mosfets and the motor survive this for some peak burdens. Very likely even more.

Exactly this could probably have been one reason for the gotway battery fires of the 2x24s2p packs.

Glowing nickel strips and/or overburdened cells.. As also KS showed - as there was at least some seconds the S20 tire erraticly turning the mosfets could have been fine fir this period...

[SanDiegoGuy]

1 hour ago, Forwardnbak said:

here it is 

How will this switch to the Samsung 40T cells change the weight and range of the new S22 ?

[Tawpie]

The 40T is a 4000 mAH/cell battery, the M50T is 5000 mAH/cell, so yes, range will suffer for 40T wheels. Weight difference won't be noticeable. For our application (sudden very high current demand) the 40T is a better choice. The 40T loses less power to internal resistance than the M50T and that's a big benefit (lower load-induced voltage sag, won't cutoff as easily under sudden high load).

Edited April 14, 2022 by Tawpie

[Paul A]

Hope buyers will be given a choice.

Would rather range than acceleration.

[chanman]

The distinction between range and usable range is an important one. For me under 20% on the S18 is close to unusable, I can limp back home at 10-15mph for a couple miles but not much else. With high power cells I might get a good bit of that back as fun range, making the 20% less capacity sting much less, in addition to the potential efficiency boost.

[Cress]

Batteries are one component that leads Manufacturers to product failure.  EUC Manufacturers and Users need factual information and rational discussion about what we expect from Li-ion batteries.  @sevin7, in his post above, has the most important point: Li-ion battery performance depends on how the battery is used.  The battery industry already has solutions for powering industrial tools, trucks, cars and airplanes.  EUC Manufacturers need to catch-up with the technology, work with factual data and listen to the Battery Manufacturers.  EUC Distributors are on a campaign to force a resolution; we should hope the Distributors succeed.

[Tawpie]

Lower range is indeed an issue... it wasn't stellar to begin with but I think some of the disappointing range is due to the crazy way the voltage of the M50T packs fell off a cliff when they were low on charge. The 40T should actually help immensely in this regard and KS may not have to kick us off as quickly... I'm crossing my fingers that we're not looking at a 25% range reduction and that the 40T's lower internal resistance will recover some of that.

The downside for me is that literally the only reason I am willing to drop another $3200 into a wheel is my S18's range is insufficient. Perhaps the 40T will still be enough of an improvement over the S18, but given the option I'm glad to see the 40T and would have to choose it and trade the range. It provides more design margin against overstressing a battery cell, and that's critically important in my mind. Overstressing cells is a known cause of rapid disassembly with loud report type failures (I vape too, so I keep a close eye on this kind of thing from another viewpoint—a battery blowing up in your hand is quite unwelcome)

Edited April 14, 2022 by Tawpie

[Rollin-on-1]

2 hours ago, Tawpie said:

The 40T is a 4000 mAH/cell battery, the M50T is 5000 mAH/cell, so yes, range will suffer for 40T wheels. 

This remains to be seen.  It would seem logical to assume lower ah = lower range, but the are a lot of comments to the contrary.  I have read where some people think it could actually increase range for some scenarios (heavy riders on steep hills is one scenario I've seen mentioned).  I think the 40T is a better cell choice and I hope the range is not affected significantly. 

[Tawpie]

To illustrate how one might explain what happened to @Seba during his range test where he got dumped...

This is the voltage curve of the M50T at various states of charge (charge used is the x axis) and current draw (colored lines). The S20 seemed to start acting like its battery was too low (tilt back, dumped Seba) at an indicated 30% remaining, so on this chart you want to look at around 3600 mAH used.

When you're cruising along with 30% remaining drawing say just under an amp (magenta line), your per-cell voltage is probably around 3.5V. When you goose it, or it has to pull current to keep you upright, or you hit a teeny bump the current draw will go up. Say it goes to the red line, 5A. Now, each cell is at something like 3.3V which is about where Begode will cutoff. KS historically has let you go to 3.0V and we don't know where their bottom line is on the S20 but if your bump wants 15A, KS is likely to shut the motor off because the cell voltage will drop below 3.0V. I think this is what happened to Seba.

 

Same chart for the 40T

With the 40T, Seba would probably have never made it to the 3600 mAH used stage... voltage cruising along at 0.8A is ~3.1V so it's likely KS would be hollering about your device battery is low time to charge etc (if it had a speaker). We'd have to back up to about 2800 mAH used to see 3.5V cruising along. BUT.

If we decide that 'safe' range is when you can deliver a 15A demand without the cell voltage dropping below 3.0V, the 40T can do that until you've used ~3300 mAH, which is actually HIGHER than the M50T which crosses the 3.0V line at ~3100 mAH used. It's probably not going to let you use 3300 mAH before it kicks you off (it might, cruising voltage is 3.3V at 3300 mAH used!), but this is why I'm hoping the range penalty won't be the full 25%!

CAVEAT: mAH is not equal to miles travelled... it's sort of an indicator because it's part of the equation, but miles travelled is a function of power consumed. I'm making the coarse assumption that the voltages are close enough to the same to allow current to stand in for power.

Edited April 15, 2022 by Tawpie

[Paul A]

Half 40T, half M50T wouldn't work?

[chanman]

4 minutes ago, Paul A said:

Half 40T, half M50T wouldn't work?

Battery balancing nightmare. Different voltages and resistances when you draw current. All kinds of awfullness. Some funky thing where you use the high capacity to recharge the high current that actually powers the wheel could be funny though, but is somewhat pointless because the effective current draw on the high current cells is much higher.

Edited April 15, 2022 by chanman

[goatman]

Molicel is bringing out P45B, like the P42A but 300 extra mah and can be used at -40 

i tried to get 100 from the Molicel Warehouse in Maple Ridge BC

i was sooo close to getting them but got denied after many emails

the 40T is one cell that regen doesnt damage it unlike many other cells and you can recharge it immediately with high amps to almost fully charged in less than hour with no ill effect to cycle life

Edited April 15, 2022 by goatman

[Eucner]

5 hours ago, Tawpie said:

I'm hoping the range penalty won't be the full 25%!

(5000 mAh - 4000 mAh) / 5000 mAh * 100% = 20%

[techyiam]

13 minutes ago, Eucner said:

(5000 mAh - 4000 mAh) / 5000 mAh * 100% = 20%

But but but, @Tawpie may be thinking:

(5000 mAh - 4000 mAh) / 4000 mAh * 100% = 25%

After all, the production models of the S22 will now come standard with the 40T's, making the 4 Ah a reasonable reference to base. 

[Eucner]

28 minutes ago, techyiam said:

But but but, @Tawpie may be thinking:

(5000 mAh - 4000 mAh) / 4000 mAh * 100% = 25%

I know. That would be extra, not penalty.

[techyiam]

1 hour ago, Eucner said:

I know. That would be extra, not penalty.

Losing 1 Ah has to be considered a penalty as opposed to a gain. For example, 4 Ah instead of 5 Ah is 1 Ah less, or in this case, it can be construed as 1 Ah penalty. The only question remains is how that is compared to. Either way is not unreasonable. 

Edited April 15, 2022 by techyiam

[chanman]

5 to 4 is a 20% loss. 4 to 5 is a 25% gain. You compare to the original value. Standard procedure, applies to everything. 

[Chriull]

9 hours ago, Tawpie said:

I'm crossing my fingers that we're not looking at a 25% range reduction and that the 40T's lower internal resistance will recover some of that.

If you look at the discharge graphs you linked in your above post the m50t delivers at 15A ~2500mAh downto 3.15V, the 40t delivers at 15A ~3080mAh.

At some 7-10A they could deliver about the same capacity.

With some 30A battery current at lower batteries ~100V that 3 kW is a likely continously possible burden. 

Going up some incline at higher speeds should give enough burden for range equality.

Edited April 15, 2022 by Chriull
4*7 is 28 and not 49 ;)

[Rawnei]

Wrong Way Adam comparing torque on S22 to 16X and concludes S22 has better torque 😅 https://instagram.com/stories/mr_wrongway/2816416783602654601?igshid=MDJmNzVkMjY=

[supercurio]

9 hours ago, Paul A said:

Half 40T, half M50T wouldn't work?

Yes that would absolutely work: one way to do that could be left pack of LG M50LT, right pack Samsung 40T.
No voltage equalization issue, draining would simply keep both packs at the same voltage in real-time, just like when you put a small pack in parallel with a big pack.

It could be an interesting in-between blend of both characteristics I must say.

As illustrated in this video:

 

[Paul A]

SuperCurio, ok, interesting, thanks.

Look forward to thoughts and discussion of others.

[chanman]

It introduces complications and shouldn't be done. Charging? Was simple, now is complicated. 40T pack is lower resistance and lower capacity and so is going to try to charge significantly faster than the 50E pack. Same with discharging. Maybe you get a big current flowing between the two packs to equalize the voltage. These are potentially manageable problems with BMS protections and careful monitoring of the systems, but no way would I want it in my wheel.