Begode Master 134V 2400WH Suspension

[The Brahan Seer]

So from Kevin's vlog above I have 2 questions: 1)The software on Begode's Master will start to limit the speed at <40% Battery. Is this due to potential low voltages causing cutoffs and does that effect all wheels? 2)  No redundancy if the battery fails due to series configuration. The question I now have is; how dangerous is that? or are battery failures very rare so not really an issue? 

[alcatraz]

2 minutes ago, The Brahan Seer said:

So from Kevin's vlog above I have 2 questions: 1)The software on Begode's Master will start to limit the speed at <40% Battery. Is this due to potential low voltages causing cutoffs and does that effect all wheels? 2)  No redundancy if the battery fails due to series configuration. The question I now have is; how dangerous is that? or are battery failures very rare so not really an issue? 

I saw the video too. I liked it.

All wheels reduce speed at lower voltage. There's nothing really different with the master other than it being a high power wheel, it also needs ample battery charge to back that up. The battery pack is not hugely different from older wheels, just higher voltage. So if other wheels limit speed at 30% then then Master might start to do so at 40% or at a relatively higher level. If it had a huge pack like the commander, that wouldn't be necessary.

Connecting packs in series does reduce redundancy. Upon learning that, my thoughts were different than Kevin's. I thought that the wiring, connectors and traces on that board need to be extra beefy. Why? Because there aren't multiple packs sharing the current anymore. 100% of the current goes through all the wires.

To answer the question of redundency, ask yourself. How often are there pack failures?

The first thought to mind might be the blowing up of a cell killing the wheel mid-ride. I don't really see that happening unless you pick high capacity cells and abuse them thermally. I'm more concerned about the connectors, cables and the nickel strips. Begode packs do sometimes use less nickel than required, and if you're going to run the ENTIRE pack current through every piece of nickel in all the battery modules, then it worries me that one strip overheats and breaks, cutting off the power. 

BUT... I'm not a pro builder or anything. I'm just an amateur. 

[supercurio]

I'm still wondering how the 4 packs in series are balanced. I guess there could be 2 approach:

• charging board communicating with each pack to tell their BMS to drain all cells using the existing balancing resistors.
• an active balancer for this "4s" configuration (capable of handling more current to balance these high capacity packs)

[Chriull]

11 minutes ago, supercurio said:

I'm still wondering how the 4 packs in series are balanced. I guess there could be 2 approach:

• charging board communicating with each pack to tell their BMS to drain all cells using the existing balancing resistors.

That's not needed. Bleeding resistors are applied once a cells voltage is above 4.2V until it's below 4.19V again.

Even the single cell overcharge sync needed for paralleled BMS is not needed anymore, as if one pack cuts the charging, charging is automaticly cut for all packs.

[supercurio]

5 minutes ago, Chriull said:

That's not needed. Bleeding resistors are applied once a cells voltage is above 4.2V until it's below 4.19V again.

Oh you're right I missed that, it simply happens automatically that way!

Thanks for explaining 👍

 

5 minutes ago, Chriull said:

Even the single cell overcharge sync needed for paralleled BMS is not needed anymore, as if one pack cuts the charging, charging is automaticly cut for all packs.

Good point.

Then it makes it unlikely that they added communication between the packs and the mainboard there (needed to handle faults during discharge instead)

[Grimm10]

I sure am glad that there a lot of individuals here that know a bunch about these battery thingys and BMS doohickys.  My brain hurts just looking at these posts!  Thanks for keeping the manufacturers in check.

I just want my wheel to ride! 

[Paul A]

 

[Flying W]

The master is looking pretty darn good. Too bad they didn't do a better handle but everything else is looking nice.

RST low end but with much more headroom on top. I'd love to see an option like this without the suspension. Just 134v RST. 

I love the idea of suspension. I have a bum knee and I like off road riding so suspension would be great. I just don't want the extra wear and tear. All my non suspended wheels have thousands of trouble free miles on them, even my stock gen 1 RS bearings (repacked with marine grease from day one). 

Having said that, if product starts flowing globally again some day and Ewheels has a master that I can just buy without a pre order new wheel itis may get the best of me 

[wstuart]

2 hours ago, Paul A said:

 

....... so its a 268v Segway.  I'll take one..... or two I guess.

[Tawpie]

4 hours ago, alcatraz said:

Begode packs do sometimes use less nickel than required

I think @RagingGrandpa found nickel plated steel in the 900 wH packs he was trying to blow up, but it would be a major stunner if the LiTech options did so. This is of course, making the assumption that LiTech is truly 'better' at pack design (to me, they're a 6 year old company that was chosen by eWheels but who don't yet have a very long track record with EUC packs). I'll assume the best!

 

4 hours ago, alcatraz said:

it worries me that one strip overheats and breaks, cutting off the power

This is to me the weakest point in the serial pack design—connections. If you do a MIL-STD reliability prediction, you'll find that the highest probability of failure lies in the interconnections—physical connectors, wires and solder joints. To ensure high reliability, you want to pay extra attention to detail: your welds, your wire sizing, your solder, stress relief for your wiring and connectors, corrosion protection, how the assemblies flex under vibration and bending moments, thermal expansion etc. There are a lot of single points of failure, so you have to be extra retentive about your processes.

BG has to know this, at least they know this in the Engineering spaces. If they have gotten their assembly processes nailed, the serial design shouldn't be (much) riskier than the traditional techniques. Nailing the assembly process is however, a key aspect that can't be ignored. There is no room for being sloppy or cutting corners. BG assembly sort of has a certain reputation that we know, accept, and in a perverse way love. The old ways won't be as 'ok' with this design.

4 hours ago, alcatraz said:

How often are there pack failures?

They happen! S18 had problems with their packs early on (evidently a rogue screw). We are all aware of battery fires. I had my bonus 16X pack that was damaged in transit and faulty on delivery. The first 'consumer' S22 is currently out of commission due to an unspecified battery problem. People charge them willy nilly, they're stored and operated in all kinds of environments. Battery packs have a lot of parts with high mass and each part (battery cell) is asked to perform within a very specific envelope after doing cartwheels at 40 mph. There are plenty of "my wheel doesn't charge properly" requests for assistance.

All this stuff is great to discover, and makes me really happy there's a diverse community asking questions and exploring answers! It drives home a very important thing about EUC ownership: Know your wheel, understand its foibles, do what you need to do.

I still want to see a Master battery pack opened up… both the BG build and the LiTech build. What, if anything, makes a LiTech battery 'better' than BG?

Edited April 27, 2022 by Tawpie

[chanman]

37 minutes ago, wstuart said:

so its a 268v Segway

Nah, those masters are clearly in parallel. If he took a sideways stance it could be a 268v scooter maybe.

Edited April 27, 2022 by chanman

[Freestyler]

On 4/22/2022 at 3:30 AM, supercurio said:

PWM is the good stuff, but what about PwmLimit?

I did some further digging and I found the PWM alarm of the master to trigger at 840, but with a maximum value of 1050 (what you see in the pwm_limit)

840 of 1050 is 80%, so that's the standard pwm percent for 100v gotway wheels. (75% for 84v).

 

it turns out that pwm_limit is present in all wheels, but not exposed in the extended packets like in the Master.

In the mcm5 the max pwm_limit is at 980 for example.

 

If someone gets a master we can verify the above

[Rawnei]

I wonder about LiTech, how come they are so well known now and almost trusted choice? Can't be just because of eWheels? Any of you have any insight into their assembly process? Do they truly produce higher quality packs?

[Ronin Ryder]

 

[RagingGrandpa]

18 hours ago, Rawnei said:

LiTech, how come they are so well known now and almost trusted choice?
Any of you have any insight into their assembly process?

More info on LiTech packs below, please let's have LiTech-specific discussions in that thread: 
https://forum.electricunicycle.org/topic/22147-ewheels-contracts-outside-company-for-custom-battery-packs/?do=findComment&comment=386126

[Rawnei]

26 minutes ago, RagingGrandpa said:

More info on LiTech packs below, please let's have LiTech-specific discussions in that thread: 
https://forum.electricunicycle.org/topic/22147-ewheels-contracts-outside-company-for-custom-battery-packs/?do=findComment&comment=386126

Thanks, I've ordered a Master with Samsung 40T LiTech assembly now, it costs more so it's not an "obvious" informed choice to make.

[supercurio]

@ray rokni shows us what's in these plastic battery boxes on the Master now!

 

[redfoxdude]

Love Ray's perspective, ha! =) Really looking forward to when someone like EcoDrift does a deeper dive and shows us the BMS

Edited April 28, 2022 by redfoxdude

[supercurio]

Now that we have a visual of what the pack looks like from the outside, I'm already wondering about the feasibility of adding a 4 Smart BMS, with the purpose of

• Monitoring and logging each cell group voltage as well as pack temperature over a certain amount of time
• Ringing a beeper in case a cell group goes too low while riding
• Ringing a beeper in case of over-temperature

Since all packs are in series, 2x 16s BMS would do the trick isn't it?
Then I was thinking for a while of programming a MCU connected to these 2 BMS to do the data logging, and expose both as a single entity over Bluetooth LE.

[Rawnei]

2 hours ago, supercurio said:

@ray rokni shows us what's in these plastic battery boxes on the Master now!

 

Just a small observation, it was speculated before if the cable sleeve went into the battery case or not and you can see that it does so in the video beginning at 4:45 timestamp.

[Nick McCutcheon]

Hmm, I thought we were told 40T manufacturing would come after 50E? And now with this new development, there's no way for someone to be sure of their pack type without opening their packs...

Its always one step forward (pick a number) steps back with these guys 🤦‍♂️

[Tawpie]

1 hour ago, Nick McCutcheon said:

Its always one step forward (pick a number) steps back with these guys 🤦‍♂️

let's see... one label implies 50Es based on capacity, another label says 40T. Hopefully the labels on the cells don't say molicel…

[techyiam]

Well, we are talking about Chinese EUC manufacturers, right? I suppose Begode didn't want to make anything harder than they have to. Putting on different labels to match battery packs is such a chore. They could have put on the label all the possible capacities. Or better yet, just don't put a label on the wheel, if they are going to be like that. Me thinks, they really should have put a label on the packs' cases, though.

I guess there aren't much to complain about, so we might as well complain about something, like labels.

[Rawnei]

6 hours ago, Nick McCutcheon said:

Hmm, I thought we were told 40T manufacturing would come after 50E? And now with this new development, there's no way for someone to be sure of their pack type without opening their packs...

Its always one step forward (pick a number) steps back with these guys 🤦‍♂️

My guess just using imagination and at least for the first batch is that the factory just slaps the same 2400Wh label on all the wheels out of routine, like it's one persons job to do that or something just unmindfully sticks a sticker on them, then later someone else mount the various batteries and ignoring or doesn't even think about the discrepancy of the label. I'm sure the battery cases comes clearly labeled from wherever they are assembled to Begode factory so it would take a lot for them to put the wrong cells on. This is all speculation of course and we know that Begode historically had silly problems with QC at assembly.

[supercurio]

I'm gradually getting set on ordering a Begode Master and build a Smart BMS monitoring solution for it.

So I got in touch with @Jason McNeil and LiTech to see if it's possible to enable some kind of collaboration now.
Chatting with @enaon yesterday, he pointed out that the solution could possibly also be retrofit to existing 900 Wh packs.

But I'll likely start with a working proof of concept on my wheel and scaling it up from here.