Begode Master: which battery option to choose?

[Lets Do Science]

What battery are you guys getting and why? 

My preorder is in through EUCO, I went with the P42A Molicels because from what i gather it's the highest performance battery available right now and solid choice for future proofing the wheel. 

[RagingGrandpa]

Worth it's own topic, as I think many customers will be facing this dilemma  

[dangasaur]

40T but I really really would like to see a direct 50E vs. 40T/P42A comparison.  I want the better battery performance of the 40T but not if it means that my total range is worse than my V11.

[RagingGrandpa]

On 3/29/2022 at 1:55 PM, Mrd777 said:

Ewheels choices are Samsung 40T 35A 1,920wh or Samsung 50E 10A 2,400wh. Same price for either.

What choice is best folks?

On 3/29/2022 at 3:12 PM, RagingGrandpa said:

It depends on your opinion of the safety of popular 40mph 24s4p EUC's like MSuperRS. 
 - If they seem scary to you, choose 40T and sleep better at night. 
 - If they seem normal to you, choose 50E and enjoy >15% more range.

Master is 32s4p, so there's going to be a little less current than RS, making either choice an improvement.

(I don't ride >38mph, so I'm in the "50E" camp fwiw)
 

On 5/14/2022 at 1:21 PM, supercurio said:

One thing we can learn here is that on the Master with 50E cells, you must decelerate as soon as you hear the first beep.
If you keep a constant speed following the first beep like Andrew did, the battery voltage sags down so quick that the safety margin goes from 20% to 0 in a second, ending up in an overlean crash.

Would not be as bad with Samsung 40T or Molicel P42A.
Is the PWM alarm well calibrated in the Master? I'd argue that at least for the 50E version it is clearly not, riding beeps like he did is not uncommon on other fast wheels.

On 5/28/2022 at 10:57 PM, alcatraz said:

Sustained power output = 40T

Short bursts = 50E

It's also a longevity thing. The 40T cells are in their comfort zone. The 50E cells possibly aren't.

When they aren't they age faster and develop issues.

On the S22 you can see cell voltages. On the Master you can't so long term ownership is going to be a bit tricky. (determine pack health, do something about issues in time etc)

On 4/17/2022 at 1:14 PM, Adel said:

When comparing Samsung 40T versus Samsung 50E, it seems the cycle life of the 40T is much worse:

Samsung INR21700-40T:

Capacity ≥ 2,400mAh @ after 250cycles
(60% of the standard capacity @ RT)

Samsung INR21700-50E:

Capacity ≥ 3,802mAh @ after 500cycles
(80% of the Rated Discharge Capacity @ RT)

So start off with less capacity to begin with, and degrade it over time at twice the rate of the 50E ? I'm trying to decide between the 2 options and want to see what is practical benefit of the 40T,for example is the firmware and components different to take advantage of the extra capability or is it just potential performance that is not tapped fully. For non-agressive riders (cruising between 25-35 mph), is there any benefit to the 40T.

 

On 4/9/2022 at 10:22 PM, supercurio said:

I'd give Marty a Samsung 50E config, and U-Stride a Samsung 40T one. As well as forbidding him to even try the 50E version 

(For context: U-Stride was the beep humper that burned the S20 prototype's control board, leading to a pack fire...)

 

8 minutes ago, Lets Do Science said:

I went with the P42A Molicels because from what i gather it's the highest performance battery available right now and solid choice for future proofing the wheel. 

"Highest performance" is misleading... 
Compared to Samsung 40T, yes, P42A is better in every way. And costs more.
Compared to Samsung 50E, there is a substantial difference in total energy (a.k.a. range). The gap narrows with faster riding (discharge rate). 

In my humble opinion:
If you're not riding above 40mph, 50E is the obvious choice. 
40+ riders, your decision warrants more consideration. 40T is cheap and perhaps safer to ride (less voltage sag means less likely to overlean). P42A is even better in cold weather. (But who enjoys riding 40+ in freezing temperatures? )

And there is no especially wrong choice- this is a topic of optimization, not necessity  

[Rich Sam]

I just had this choice on my new RS19.  I chose P42a as well, this is going to be my dedicated single track trail wheel so range is not that big a deal.  I'm a heavy rider, so I want the extra mustard on it.  Plus, I want the security\piece of mind that the cells are being discharged at their approved output ratings, I want to reduce possible fire issues.

[Tawpie]

26 minutes ago, Lets Do Science said:

What battery are you guys getting and why? 

My preorder is in through EUCO, I went with the P42A Molicels because from what i gather it's the highest performance battery available right now and solid choice for future proofing the wheel. 

If you can see yourself routinely tapping into the speed or torque the Master offers, I'd for sure go Molicel. Just to provide that extra margin against degrading the batteries with 'normal' use.

If you're just looking at the additional speed/torque headroom for use in only in emergency/occasional situations, then you're probably ok enough with the high capacity cells from a degradation standpoint—and you should get a bit more range. Think about it though—how can you not take advantage all that performance?

Battery replacement is so terribly expensive I'd want to hedge my bets against early failure, but the Molicel option is already eye wateringly costly so it's a tough call. Especially since so far, and it's still early, the high capacity cells seem to be holding up (sample of one, but RogerH does not go slowly very often).

Edited July 6, 2022 by Tawpie

[RagingGrandpa]

2 minutes ago, Rich Sam said:

extra mustard

To be clear- all 3 cell options will deliver the same motor torque at low speed.
(... because the motor torque is limited by the controller's electrical current limit; not the battery.)
 

3 minutes ago, Rich Sam said:

single track trail wheel
I'm a heavy rider

Singletrack MTB is all <30mph in my experience, limited by the terrain, not the machine. 
Since this is easily within the current-limited speed range of the motor, voltage sag doesn't matter, and you should expect equivalent acceleration among all 3 cell options.
 

6 minutes ago, Rich Sam said:

I want the security\piece of mind that the cells are being discharged at their approved output ratings, I want to reduce possible fire issues.

This is quite valid.
It's a fire safety argument; not a performance argument.
I support it   
But we do have lots of community experience with 4P 21700 50E packs now, in MSuperRS used aggressively by big dudes offroad... so there are reasons to sit on both sides of this decision.

[Rich Sam]

45 minutes ago, RagingGrandpa said:

To be clear- all 3 cell options will deliver the same motor torque at low speed.
(... because the motor torque is limited by the controller's electrical current limit; not the battery.)

-- I feel the p42a will deliver more consistent power across the capacity band, deeper into the cycle because of far less sag.
 

45 minutes ago, RagingGrandpa said:

Singletrack MTB is all <30mph in my experience, limited by the terrain, not the machine. 
Since this is easily within the current-limited speed range of the motor, voltage sag doesn't matter, and you should expect equivalent acceleration among all 3 cell options.

Yessir, I plan to go above 30 sparingly   I feel voltage sag plays a role, maybe not as much as its being market.  If your voltage is in a major SAG then to continue the same power output will require more amps for the equivelant power.  More amps, more heat, more wear and tear.

 

Edited July 6, 2022 by RagingGrandpa
(bugfix quote)

[Tawpie]

6 minutes ago, RagingGrandpa said:

the motor torque is limited by the controller's electrical current limit

Has anyone figured out where this limit is set on Master?

[Rich Sam]

12 minutes ago, Tawpie said:

Has anyone figured out where this limit is set on Master?

without looking at the circuits and eyeballing the fuses... 3500 Watt motor at 120 volts, probably between the 30-40 range-ish

[RagingGrandpa]

29 minutes ago, Tawpie said:

Has anyone figured out where [the motor current limit] is set on Master?

@Freestyler had some evidence showing it might be 220A, same as RS:HS... but hardware and firmware are still in a state of flux for this new EUC.

On 5/10/2022 at 5:59 PM, Freestyler said:

I

 

18 minutes ago, Rich Sam said:

3500 Watt motor at 120 volts, probably between the 30-40 range-ish

That's battery current, which is not 1:1 with motor torque...

[chanman]

1 hour ago, RagingGrandpa said:

If you're not riding above 40mph, 50E is the obvious choice

I don't think speed is the only consideration when picking cell types, steep climbs and big jumps will demand a lot of extra current that I'd prefer to have the high drain cells for.

[Freestyler]

1 hour ago, RagingGrandpa said:

@Freestyler had some evidence showing it might be 220A, same as RS:HS... but hardware and firmware are still in a state of flux for this new EUC.

That info was from the initial Master firmware releases, so I took another peak at the latest firmware to see if something changed.

The value is still 220a. The higher voltage requires less current for the same watts though, so 220a is a lot higher than other wheels when taking this into account.

 

We might perform a test with @Mike Sacristan and set this value to a low number such as 50.

If it indeed controls the current limit, then a lean against the wall will quickly prove it.

Edited July 6, 2022 by Freestyler

[RagingGrandpa]

9 minutes ago, Freestyler said:

higher voltage... so 220a [phase current] is a lot [more output] than other wheels

Why's that?

Master is the good ole C38 motor... 220a in the Master will make the same torque as 220a in an RS:T. 

[Rich Sam]

This is a good debate!  The attributes of the different cells may not be easily measured in the field, and the benefits\drawbacks may not be reaped right away, but over time in the form of more\less wear and tear.  I just unboxed my P42a RS HT.... Excited to give it a go tonight!

[Freestyler]

19 minutes ago, RagingGrandpa said:

Why's that?

Master is the good ole C38 motor... 220a in the Master will make the same torque as 220a in an RS:T. 

I might be completely wrong about the things I will write below. I don't claim to understand these things well. 😛

My train of thought was this:

P = V * I

Since volts in master increased by 34% over the 100v wheels, then current drops by the same amount for the same power.

 

Example for 134v wheels:

5000w / 134v = ~37a

For 100v wheels:

5000w / 100v = 50a

 

34% percent difference.

I know those are battery amps and not phase amps, but I guess the relation stays the same?

So having a 220a current limit in 134v wheel is the same as having +34% = 295a in a 100v wheel.

Edited July 6, 2022 by Freestyler

[Tawpie]

@Freeforester you are correct. Power is a direct linear relationship.

The reason I was curious is the translation of motor phase current to current pulled from the battery pack (sort of that the topic is) can give you an idea of how much the wheel will pull "on purpose", and that should give some insight into how much to expect each of your cells to be asked to produce.

If we use the very rough motor phase current ~= 3x battery current, then 220A of phase current could be expected to represent about 72A out of the battery pack. A 4P 10A arrangement would be good for 40A before you leave their comfort zone, whereas the p42a at 45A/cell continuous would support 180A (540A of phase current).

In other words, and assuming I have this correct, the firmware will allow 'over' current stressing of the high capacity 10A cells—how frequently depends on the rider and other factors. But the 45A p42a and the 35A 40T are able to comfortably support any current demand allowed by the firmware, even if your ride style is so aggressive that you are able to use your entire pack in 15 minutes (without melting something else!).

Edited July 6, 2022 by Tawpie

[RagingGrandpa]

1 hour ago, Freestyler said:

having a 220a current limit in 134v wheel is the same as having +34% = 295a in a 100v wheel.

I disagree. In the friendliest way possible  

Instead, it is: if the motor current reaches 220a, it will give the same torque regardless of controller input voltage.

  

1 hour ago, Freestyler said:

P = V * I

That's a steady-state or "average" power. 

For a steady riding condition, the input power to the controller is steady, and determined by the lovely constant battery voltage, and the battery current like you mentioned.

But the controller's output power is realized by a pulsating sequence of activating 3 phase windings, each experiencing a choppy voltage (a result of PWM done by the controller) and a sinusoidal current. Nothing here is 'steady' - so it's not as simple as V * A. 
With an input of 134V instead of 100V, the PWM duty will be lower, to reach the same 220a current limit. But the RMS voltage will be equivalent, and the output power will be nearly identical, in our maximum-lowspeed-torque example.

I think power is not the interesting quantity when we're talking about torque, acceleration, or forces that the rider feels. 
It's a DC motor. It makes a force that directly relates to the amount of electrical current flowing through its windings. 
You don't feel the voltage; you don't feel the power; you do feel the current   
And 220a is the limit, regardless of how much extra input voltage we have available.

.02

 

Edited July 6, 2022 by RagingGrandpa

[Freestyler]

Best way to elicit a response, is to write something wrong and they'll come to correct you

Edited July 7, 2022 by Freestyler

[alcatraz]

Is the C38 motor already torque-maxed out in previous wheels?

[RagingGrandpa]

14 hours ago, alcatraz said:

Is the C38 motor already torque-maxed out in previous wheels?

Torque could be increased, if we increase current.

But we're already pushing the durability limits of the controller, with the 250 amp motor phase current limits like MSP have. 
If you suppose an even stronger controller were invented that could output 300 amps, we would also need to check that the motor cables and windings don't overheat. 
The crappy old 14gage motor cables from MSP aren't great... but those would be simple for Gotway to upgrade, given the ample packaging space provided by the new generation of hollow motors.

Assuming we stick with with today's output current limits: yes, C38 torque is maxed out and will not improve in future models. 
(Its top speed can improve, of course...)

[dangasaur]

To all the wheel influencers out there.  If you really want me to smash that like and subscribe button, post a video with a real world range test of both battery options.

Sincerely,
Everyone with a Master Pre-order

[sway2127]

E-Rides was doing a demo day with a 50E AND a 40T a month or two ago (according to their YouTube post). I was hoping some real world comparisons would come out of that… but here we are still comparison-less

Edit: FWIW, I have an eWheels 40T pre-order and I second guess myself almost daily!

Edited July 12, 2022 by sway2127
Additional context

[alcatraz]

11 hours ago, RagingGrandpa said:

Torque could be increased, if we increase current.

But we're already pushing the durability limits of the controller, with the 250 amp motor phase current limits like MSP have. 
If you suppose an even stronger controller were invented that could output 300 amps, we would also need to check that the motor cables and windings don't overheat. 
The crappy old 14gage motor cables from MSP aren't great... but those would be simple for Gotway to upgrade, given the ample packaging space provided by the new generation of hollow motors.

Assuming we stick with with today's output current limits: yes, C38 torque is maxed out and will not improve in future models. 
(Its top speed can improve, of course...)

The latest move from Begode to reduce phase current 250 > 220 > 240, do you think that was done to protect the boards or the motors (or both)?

Maybe that was only done on the HS wheels but still, interesting nontheless.

[Tawpie]

5 hours ago, sway2127 said:

E-Rides was doing a demo day with a 50E AND a 40T a month or two ago (according to their YouTube post). I was hoping some real world comparisons would come out of that… but here we are still comparison-less

Edit: FWIW, I have an eWheels 40T pre-order and I second guess myself almost daily!

I think that if you are wanting to actually use the torque and speed, the 40T is the best choice. Time will tell, but on paper anyway, the 40T makes a lot of sense for sporty ride styles... think of it as insurance. BG has not been shy about taxing the batteries in the past. Maybe they've done an about face and have limited the Master's performance to avoid stressing the batteries? Nah.