Begode Master 134V 2400WH Suspension

[supercurio]

8 hours ago, Nick McCutcheon said:

A new video from Lukas at Begode shows the master reaching 60mph on the dyno before cutting out/overleaning

Interesting video!

There's not much information but we can still see a few key aspects, mainly:

What slows down the wheel is only caused by rolling resistance of the tire against the two metallic rollers, so all the energy dissipated which makes it different from a free-spin test is heat of bending the rubber, friction of the rubber vs metal, and sound.

I believe these will increase linearily with speed instead of what's most significant when riding at speed: wind resistance / aero drag which increase with speed² (squared)

Therefore this test shows something, but doesn't tell very much about the maximum speed with a standing or seated rider on it 😄

Edited February 12, 2022 by supercurio

[Nick McCutcheon]

10 hours ago, Chriull said:

Seems to be a "normal lift cut off speed test"?

The 80 kg load mentioned in the begonning seem to be just a static weight load on the axle and tire slightly increasing friction but not really burdening the motor.

It's not mentioned if the test rig rolls have some resistance (brake, burden) or some noteworthy weight to accelerate beeing some burden for the motor?

But 100 km/h seems a reasonable lift cut off speed for new wheels - or they already go faster?

Li Ion cells have some kind of two step sag. So the voltage should come up again. Would be strange if the battery looses 10% of the capacity from one acceleration...

Afaik every wheel cuts off the motor power once lift cut off speed is reached for some time. I'd guess exactly this happens in the video

An EUC will only break if one leans back, or on this rig one pulls the wheel back.

As written above that's some measure from every wheel at the absolute maximum speed possible without load if held for some seconds.

There are not too much reason for cut offs:

- some component failed like a fried mosfet. Behode most likely won't publish a speed test showing this.

- overtemp alarm and shutoff would imho take longer and no readon again for begode showing this.

- si this shut off after lift cut of speed reached stays as last reason? Imho.

This max speed reached is an overlean (with wheel cutting of after some short time)

Interesting. So this qualifies as an overlean since the speed caused the wheel to remove power after some short time?

Maybe I am still not sure what an overlean is, but I thought overlean = overpowering the motor while it's still trying to balance, and cut off = wheel removes power for any reason except for angle leans (45 degree forward/back and left/right). Normally this wheel has a lift speed off the dyno of 112kmh, so this 100kmh figure is different from the normal no load speed. Probably the sag caused by whatever is causing the dyno to resist movement lowers the "lift" speed significantly. Yes, one would expect the motor to remove power *while lifted*. Ideally, contrary to current behavior, it should *not* do this when someone is riding at top speed, which even though this test is not really representative of real riding, it shows that this is what happens.

Could there not be some easy logic which will only shut the motor off at top speed if little power is being drawn? This would mean it's been lifted. If there's any reasonable amount of current draw, then don't shut the motor off, since someone is riding.

Edited February 12, 2022 by Nick McCutcheon

[Chriull]

1 hour ago, Nick McCutcheon said:

Could there not be some easy logic which will only shut the motor off at top speed if little power is being drawn?

These speeds can never be reached in real life while riding an EUC. One draws much more power and hence overleans way before.

There is just a very slight chance to reach lift cut off speed going down a slight decline with the right backwind and the rider acrobaticly and perfectly balances the wheel...

1 hour ago, Nick McCutcheon said:

This would mean it's been lifted. If there's any reasonable amount of current draw, then don't shut the motor off, since someone is riding.

Motor is only shut off once lift cut off speed is reached, which is not possible while riding.

Even if one would reach lift cut off speed one would overlean as the wheel can not balance anymore at these speed - no torque anymore available.

As the motor cannot draw any current at no load speed (~lift cut off speed) as it generates a voltage equal to the supply voltage.

[Nick McCutcheon]

High speed test seems promising. I didn't really see the warning pop up in the app (didn't hear the beeper either but it's too windy) at 80kmh, so 85-90kmh at least might be sustainable. Exciting! 

[supercurio]

"power alarm set to 75%" might imply that the safety margin is user configurable?

It's one of feature I'm planning in the standardized wireless protocol for safety.

[Bizra6ot]

@supercurio Or it is chienglish translation and it is just 75% like they did with Ex/n, imho I think they only specify it to value the performance because with all the old Gotway the beeps were at 80% before the new standard

[Freestyler]

Are you saying that on the ex.n it beeps at 75%?

[EMA]

edited: begode confirm newest setting is beep at 75% power output

Edited February 14, 2022 by EMA

[Bizra6ot]

11 hours ago, Freestyler said:

Are you saying that on the ex.n it beeps at 75%?

Yes, I can't confirm it for the most recent ones released after the Ex/n like Hero ex20s and Master it is not specified on their data cards as usual but 75% could be the new Begode standard

[EMA]

yes they confirmed to me that the new standard beep will be 75% power output 

[xiiijojjo]

On 2/14/2022 at 2:31 PM, EMA said:

yes they confirmed to me that the new standard beep will be 75% power output 

Big news. I wonder what the reason is.

[EMA]

14 minutes ago, xiiijojjo said:

Big news. I wonder what the reason is.

"becouse when ignored it's easy to overpower/speed"

beeping earlier increase the margin a bit

[GoGeorgeGo]

8 minutes ago, EMA said:

"becouse when ignored it's easy to overpower/speed"

beeping earlier increase the margin a bit

I wonder if it has to do with the ramp up to 134.4v configurations. Adding that extra bit of accelration power probably makes it easier to blow through your overhead by accident. Giving an extra 5% could save someone from kuji leaning to 60+ mph

[Bizra6ot]

29 minutes ago, GoGeorgeGo said:

I wonder if it has to do with the ramp up to 134.4v configurations.

No cause they already went from 80% to 75% with the Exn

[Paradox]

AlienRides is showing two different battery configurations available.

[Paradox]

They are also calling it a lithium iron battery.

https://alienrides.com/collections/electric-unicycles/products/begode-master-electric-unicycle?variant=42485917548798

[supercurio]

Super cool Alien Ride already plans to offer high drain cell options for the Master!
Which will definitely need them to avoid massive voltage sag when riding near max speed.

Copy-paste error or mix-up on @Alien Rides description page tho, none of them are LFP / Lithium Iron Phosphate cells.
Would someone let them know?

[Paradox]

18 minutes ago, supercurio said:

Copy-paste error or mix-up

@Alien Rides

Edited February 24, 2022 by Paradox

[Tawpie]

700USD markup for Molicells. Dadgum.

[Rolzi]

[Kutvis]

18 hours ago, Paradox said:

@Alien Rides

Heh.. It is astonishing how they market the wheels "you can buy bigger battery, but it can catch fire" 🙈

[techyiam]

43 minutes ago, Kutvelo said:

Heh.. It is astonishing how they market the wheels "you can buy bigger battery, but it can catch fire" 🙈

This is possible because euc buyers have shown that they prefer more range over no of risk of fire, until their houses or apartments burn down. In fact, it looks like Begode.com has remove their lithium iron phosphate (LFP) battery models from their euc line up on their website. Interestingly enough though, the Extreme Bull K6 uses LFP.

Edited February 25, 2022 by techyiam

[alcatraz]

That's odd. Using Lithium Iron(phosphate) LiFePo4 cells occupies a lot more space than Li-Ion and the Master does not have LiFePo4 option listed. I don't quite see how they're going to offer it. To reach 134V with LiFePo4 you'd need at least 36 cells in series which would require different design battery enclosures and bms'. The wheel would also have a fraction of the range and/or weigh a lot more. I'm guessing somewhere around 1200Wh.

[GoGeorgeGo]

I am honestly a little concerned about both the master and the s20. Both are 4p battery packs but now with stepped up voltage and performance?

As we have seen, 4p packs are the most risk of thermal runaway. And imo, a good portion of that has to do with them being right in the performance demand sweet spot. They are strong enough to be ridden extremely aggressively. Both in terms of discharge and regen braking. They are also purchased by riders who demand more from their machine as in fast charging and riding in unfavorable conditions. 

Putting those extreme stressors on 4 sets of series instead of say 6 or 8, means each set is getting further and further out of balance over time. Now we have wheels here that will want even more discharge power, and even harder regenerative braking. And they are suspension wheels which we see even from the ads and demos people want to do absurd things with. Jumping , and crashing, and mud riding etc. Riders will be abusing these batteries worse than any other 4p model released yet most likely.

Thankfully the s20 has a fairly advanced BMS which knowledgeable riders will be able to monitor their battery with. But thats only helping riders who know what voltages are and how dangerous an unbalanced battery is.

I have heard a substantial claim that begode will be delivering smart bms batteries in the coming months. Ive heard future batches of the master will contain these smart bms batteries. I hope its enough to prevent serious issues. Im afraid it will only be useful for enthusiasts however. 

Hopefully both companies include firmware battery monitoring that will alert riders when and cells get out if synch and wont allow them to ride until the pack is fully.balanced

Edited February 25, 2022 by GoGeorgeGo

[alcatraz]

I noticed the S20 has a smart BMS that can show all the cell group voltages. I'm surprised it isn't talked about more. It's a big step in the right direction safetywise. 

It remains unclear if the S20 has two 30S packs or two 15S packs in series? If it's the former, then why don't we see two sets of voltages. One for each pack. Also will the Master also have a smart BMS like this?