Begode Rs Resolute, the first EUC using LFP battery chemistry?

[supercurio]

@Alien Rides just posted about a new Begode wheel, the RS Resolute.

Here's the specsheet:

Alienrides listing:
https://alienrides.com/collections/electric-unicycles/products/begode-rs-resolute-electric-unicycle

It's focused on new type of battery pack which I'm guessing is LFP based from the max voltage, but I could be wrong, we'll learn about it later:

3.65V is the max voltage for the LFP chemistry.
At 32s, we arrive at 3.65x32=116.8V

LFP doesn't thermal runaway the same as Lithium-Ion does and allows for safer battery packs. However the energy density is lower, which would be the best explanation for the 1020Wh total battery capacity.

LFP is also known as lithium-iron phosphate, or LiFePO4. It is a popular chemistry for energy storage at home for solar panels thanks to its good safety profile, longer lifecycle than lithium-ion, flat voltage curve, high charge/discharge rate, good price/capacity ratio.

LFP packs can also be found in the latest Chinese-produced Tesla 3 Standard Range +, with great results and extremely fast charging (peaking at 170kw for a 55.0 kWh pack ~ 3C)

A bonus for EV applications it that the max speed is fairly constant through the whole discharge cycle, which means the Resolute max speed will be nearly the same at 90% or 20%.

To illustrate the point in safety, Begode made this demo video where they're literally drilling into a pack.
https://www.facebook.com/AlienRides/videos/300221391996633/
Note that what you see here is not an incredible technological breakthrough by Begode, but highlights the better resilience of LFP packs.
 

Questions:

• LFP voltage curve is pretty flat: how will the board estimate the battery %. Usually, joules counting is required instead of relying on voltage
• Why did Begode choose to build a RS with a very short range instead of releasing these packs in a EX.N or Commander form factor is hard to explain.

 

Edited December 14, 2021 by supercurio
more accurate title, again

[skautas2003]

Like Inmotion V10f just with 5 kg bigger weight. With more powerfull motor and higher probability to cutout. 28 kg torque wheel with 3000 W motor and 1020 wh battery. we could vote which one this or Abrams will be better cutout machine.

[yoos]

Just now, skautas2003 said:

With more powerfull motor and higher probability to cutout

I do not agree. I am quite sure these batteries have much higher discharge current than the V10F. It is more likely to be  a powerful and fast short-range wheel, perfect for racing or speedy yet short commutes.

[supercurio]

Just now, skautas2003 said:

Like Inmotion V10f just with 5 kg bigger weight. With more powerfull motor and higher probability to cutout. 28 kg torque wheel with 3000 W motor and 1020 wh battery. we could vote which one this or Abrams will be better cutout machine.

LFP cells can typically handle very high discharge rates.

The safety characteristics, using the traditional C38 HT motor but increasing its max speed with a higher max voltage should give it rather good safety and lower risk of over-power than most other wheels - provided the board is reliable, QC is done well etc.

However the small capacity will limit the range and usability of the wheel.
But for customers who want a safer wheel and avoid li-ion fires primarily, that could be a worthy trade-off.

[yoos]

24 minutes ago, supercurio said:

Questions:

• LFP voltage curve is pretty flat: how will the board estimate the battery %. Usually, joules counting is required instead of relying on voltage
• Why did Begode choose to build a RS with a very short range instead of releasing these packs in a EX.N or Commander form factor is hard to explain.

Joule counting should be easy, you can even do it algorithmically via firmware/software from voltage and current. Every so often recalibrate "full" and "empty" from voltage curve.

I would guess that the packs might be expensive and RS is a cheaper and more popular model? Also, the RS was in need of a change since 4 m50lt packs were inadequate, while the EX.N and Commander seem more ok.

Many riders like bigger battery packs to ride at max speed for longer and the bottom half of the capacity doesn't even get much use. The LFP becomes more efficient in this regard. I would be happy with a speedy 1kWh pack for my city commuter use case. 

[skautas2003]

Ok then next question why to chose this wheel and not v12?

[supercurio]

1 minute ago, yoos said:

Joule counting should be easy, you can even do it algorithmically via firmware/software from voltage and current. Every so often recalibrate "full" and "empty" from voltage curve.

Yes I hope they'll do that!
It means that the Bluetooth protocol might need to change however since currently the wheel report fraction of voltage and not battery %.
Or maybe the board will report a fake voltage that gives the % of charge estimate in place instead.

1 minute ago, yoos said:

I would guess that the packs might be expensive and RS is a cheaper and more popular model? Also, the RS was in need of a change since 4 m50lt packs were inadequate, while the EX.N and Commander seem more ok.

Many riders like bigger battery packs to ride at max speed for longer and the bottom half of the capacity doesn't even get much use. The LFP becomes more efficient in this regard. I would be happy with a speedy 1kWh pack for my city commuter use case. 

Ah thanks for highlighting that use case.

Let's see if they also produce LFP based bigger capacity wheels. 

[RagingGrandpa]

4 minutes ago, skautas2003 said:

why chose this wheel and not v12?

• $550 less expensive (today's AlienRides pricing)
• More torque (low-speed acceleration, tricks, skate parks, racing, severe offroad)
• More durable axle (jumping)

TBD if the high-drain lower-energy LFP pack can "sustain 33mph without beeps" longer, than the V12's larger Li-Ion pack. It might be close!

 

Edited December 7, 2021 by RagingGrandpa

[supercurio]

8 minutes ago, skautas2003 said:

Ok then next question why to chose this wheel and not v12?

Yes it's interesting that instead of working on how to design li-ion packs matching the safety standard of the rest of the industry, they kind of gave up on that and switched chemistry instead.

In comparison, a V12 is also unlikely to catch fire since it comes with adequate waterproofing and BMS tech, and comes with 1750 Wh instead of 1020 Wh, 1.7x the range and capacity.

Edited December 7, 2021 by supercurio

[Paradox]

This seems like a promising development.  I for one will not be a beta tester though.

[supercurio]

1 minute ago, Paradox said:

This seems like a promising development.  I for one will not be a beta tester though.

Did the the 100.8V boards, from 84V come with an increasing amount of failure?

The spec doesn't specify if the RS Resolute uses the same black board as the 100.8V or a new one.

[yoos]

7 minutes ago, skautas2003 said:

Ok then next question why to chose this wheel and not v12?

In addition to @RagingGrandpa's bulletpoints,

• Safety! (or perceived safety ) While inmotion is generally considered safe, the switch to LFP might be crucial for some users. There are enough people (apartment dwellers mostly) for whom the fire risk is the primary reason not to get a PEV.
• there are Begode fans who like its performance approach: no enforced tiltback, minimal safety margin.
• the RS is still weighing less than the V12, although the difference is minimal

[RagingGrandpa]

On 12/7/2021 at 11:19 AM, supercurio said:

Did the the 100.8V boards, from 84V come with an increasing amount of failure?

Yes

But building competence requires experience. Glad to see the first production 116V Gotway, which makes me hopeful for future maturity of 116V systems.
HT motors that can sustain 40mph safely might become reality soon! (RS-RS and S20)

 

Edited December 29, 2021 by RagingGrandpa

[RayRay]

If LFP, it's interesting that this would debut on such an advanced wheel; rather than an entry level one.

[meepmeepmayer]

Ugh. 

The RS is a fantastic wheel you can't really buy because of the battery problems.

But 1800Wh to 1020Wh sucks.

Why not just use better Li-Ion cells? *cough* V12 *cough* Is it the Begode firmware or BMS or whatever that can't handle such cells? Do all such cells blow up when the power draw is too high, so they don't really work for such a wheel?

[Chriull]

45 minutes ago, supercurio said:

 

 

35 minutes ago, supercurio said:

Yes I hope they'll do that!
It means that the Bluetooth protocol might need to change however since currently the wheel report fraction of voltage and not battery %.

Afaik the wheels superfluously reported both - so a change should be no prob.

32 minutes ago, supercurio said:

 and comes with 1750 Wh instead of 1020 Wh, 1.7x the range and capacity.

We'll see if there is really such an easy linear correlation. High capacity 21700 liion cells as used by now loose much capacity at high current burdens.

High discharge cells, as eventually the used lifepo4 could be, could show more real usable Wh.

Also by their discharge profile more of the effective capacity could be usable?

I'd not be too much surprised if an real world factor would be below this 1.7.

Edit: or maybe i should, as the official menufacturer range already shows this factor

Edited December 7, 2021 by Chriull

[RagingGrandpa]

12 minutes ago, meepmeepmayer said:

The RS is a fantastic wheel you can't really buy because of the battery problems.

Hmm... people are still buying RS 1800wh, and loving it. Really

12 minutes ago, meepmeepmayer said:

use better Li-Ion cells? *cough* V12 *cough*

The fire risk is inherent to all Li-Ion cells, including V12.

RS production has seen 4 different cell models used in the last year (M50T, 48X, 50E, M50LT). V12 is M50LT. But they're all similar Li-Ion chemistries, and all carry risk of fire.

10 minutes ago, meepmeepmayer said:

do these batteries have less voltage drop, so you can go faster longer?

Yes.

 

Edited December 7, 2021 by RagingGrandpa

[Ben Kim]

Amazing how after all this time they can’t reproduce the MSX 100V 1230Wh.

62lb vs 48lb

88kph no load speed vs 92kph

20 mile range vs 15-16

[RayRay]

I'd like to see Kingsong use LFP's in the 14S, rather than have it compete with 16" wheels. (Make it a slight upgrade to 14D, but keep it under 1K.)

[lirva]

If they can push the price down to 1k€ this would be ok commuter wheel. 

[supercurio]

24 minutes ago, Chriull said:

Afaik the wheels superfluously reported both - so a change should be no prob.

Are you sure?
I wrote a parser for the Bluetooth data in EUC Alarm: see source code and found only Voltage - which is using 67.2V as reference. No %. Interested if there is.

24 minutes ago, Chriull said:

We'll see if there is really such an easy linear correlation. High capacity 21700 liion cells as used by now loose much capacity at high current burdens.
High discharge cells, as eventually the used lifepo4 could be, could show more real usable Wh.

Also by their discharge profile more of the effective capacity could be usable?
I'd not be too much surprised if an real world factor would be below this 1.7.
Edit: or maybe i should, as the official menufacturer range already shows this factor 

Agree! 
More of the theoretical capacity of the cell will be usable for 3 reasons:

• Because they're high drain / low internal resistance
• Thanks to the much more convenient voltage curve
• (maybe) because the voltage is higher anyway

So what's the factor compared to previous wheels using Li-ion?

[supercurio]

@yoos you mentioned commuters.

This particular wheel could also become a good option for off-roaders who need a lot of torque and power but don't really care about range.
All the advantages of the HT motor with a higher safety and top speed buffer for jumps etc.

[RagingGrandpa]

1 hour ago, supercurio said:

More of the theoretical capacity of the cell will be usable

Yes but... the reduction is capacity dominates the story.

• Li-Ion 18650GA delivers about 75% of its "label capacity" for an EUC, before tiltback voltage (end of useful capacity).
• LFP 18650 delivers about 85% of its "label capacity" in a similar theoretical EUC. But the label capacity is less than half of the Li-Ion 18650.

So to get a 10% bump in 'discharge efficiency,' you gave up half of the original rating. It's a net loss.
(And no surprise, as LFP has been on the market for decades now.)

The old story was: The main thing that LFP can do that Li-Ion cannot is: 20A per 18650-size cell. (And be immune to thermal runaway.)
It means an MTen3-sized pack could power a Sherman-sized motor. For about 5 minutes
But with new designs, the industry managed to get Li-Ion 18650's up past 20A, leaving LFP behind in terms of discharge performance.

 

Edited December 7, 2021 by RagingGrandpa

[Chriull]

2 hours ago, supercurio said:

Are you sure?

No. It was just logged from wheellog afair quite from the beginning. So i always thought that's reported and not calculated...

But should be easily seen on github, if that's not one of your sources anyhow.

 

 

[Tawpie]

Tesla is switching their US cars to LFP... some (4%?) drop in range, partially made up for by the ability to charge LFP to a higher state of charge than is recommended for their current NCA chemistry. Reason: probably cost

 

https://www.cnbc.com/2021/10/20/tesla-switching-to-lfp-batteries-in-all-standard-range-cars.html

Edited December 7, 2021 by Tawpie