SZZS specific CEF50-main thread (initial builds and troubleshooting related only)

mike_kelly

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There is nothing to fix on the battery. Lithium batteries can be destroyed by discharging to zero. So how far is safe? That is a religious argument among engineers. But 80% is a generally accepted safe point. Down to 15% left is considered ok by a few. But that is the range. Never heard anyone arguing in favor of less than 15%.
The batteries are expensive and I for one want mine to last as long as possible. I'll just bring my external battery for longer distance.
 

TCFlowClyde

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There is nothing to fix on the battery. Lithium batteries can be destroyed by discharging to zero. So how far is safe? That is a religious argument among engineers. But 80% is a generally accepted safe point. Down to 15% left is considered ok by a few. But that is the range. Never heard anyone arguing in favor of less than 15%.
The batteries are expensive and I for one want mine to last as long as possible. I'll just bring my external battery for longer distance.
Sure, I'd go 15%. But if you really want to live life on the edge, 10% is where true mavericks dwell.🤠

Note; My Dengfu M620 fattie is 12% reserve. Luv'n it!🤟
 
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Neeko DeVinchi

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The mic definitely amplifies. Maybe have a 3rd person perspective from hiker on the ground?🥾
Usually, I do use a wind muffler around the gopro. But on this occasion, I thought it best to have the unedited sound.
But you are right. The motor isn't as loud with the human ear compared to the gopro audio recording. But I'd be lying if I said that the motor couldn't be heard when achieving peak output.

But I wouldn't mind re-shooting footage in better light. So I'll perform the same test (or maybe something steeper)👍🏿
 

TCFlowClyde

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Usually, I do use a wind muffler around the gopro. But on this occasion, I thought it best to have the unedited sound.
But you are right. The motor isn't as loud with the human ear compared to the gopro audio recording. But I'd be lying if I said that the motor couldn't be heard when achieving peak output.

But I wouldn't mind re-shooting footage in better light. So I'll perform the same test (or maybe something steeper)👍🏿
Sure it's most audible in boost mode and much less gradual as the power down happens, but I wonder how loud it is to the hikers on the trail? Just curious.

I'd try my mobile phone camera myself with a buddy but the go pro catches truer sound at higher quality. 👍
 

mike_kelly

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Sure, I'd go 15%. But if you really want to live life on the edge, 10% is where true mavericks dwell.🤠

Note; My Dengfu M620 fattie is 12% reserve. Luv'n it!🤟
The problem is that going below 20% is going to reduce the number of charge cycles over the lifetime.
 

streyer

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Feb 27, 2020
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I know it’s been a while since you posted this file, but I just got around to installing it and testing it yesterday evening. My friend, you’ve made a significant improvement of the quality of ride by producing this firmware, thank you.

Some of the highlights:

– smoother power delivery
- punchier power delivery
- Less delay time to start power delivery under-load
- battery lasts longer using more power somehow
- much more noticeable difference between modes, primarily Eco mode you can actually feel the right away, sport plus has everything I need to get me up the steepest sections
- The downhill, application of pedal strokes to keep momentum, the spin up time doing this feels much more natural and less delay

I can’t send enough good things about this firmware. It’s a significant improvement over stock. Did you figure out how to get full power delivery below 25%.? I would love it if you could ride at full power down to about 10% before a reduction in power.

This ride below was going between sport and sport plus and I was still left with about 44% battery at the end of the ride. This would’ve normally been 35%-ish, I only know that because the day before I did a similar ride and I ended up round 30%.
View attachment 129018
Hi sir, we tried flashing from 3.3 to this firmware and was not able to, will you be able to advise what version of bafang app you use to flash it?
 

brbr

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The problem is that going below 20% is going to reduce the number of charge cycles over the lifetime.
I've noticed in the 43V version I'm using (the one shared on the forum), the power will slightly reduce at 20% then again around 13%, it's not all boost and then eco, there are steps, which is quite cool
 

TCFlowClyde

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Feb 26, 2022
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The problem is that going below 20% is going to reduce the number of charge cycles over the lifetime.
I understand. Just want a little more before reserve...more fun for a few less cycles is the tradeoff, especially every 10 rides or so. That is, on the rare occasions and longer adventure rides.🤞 1000 - 100 = 900 cycles left over 5 years very acceptable to me.😎 10-15% is more standard by the big brands too.

Plus, the big 720Wh makes range/power anxiety even rarer...thankfully. See another tradeoff, more battery weight for more ride, but more fun! 💪 Trade offs that equal more fun, especially at cheaper DIY price, is worth it to some, others less so. 🤑

Now if it was a future EV truck and daily driver, you're damn right!👊 I would be preserving that super expensive battery at all costs! Probably never dropping below 20% between charges. (Like I do with gas. Try not to drop below 1/4 tank to save my future fuel pump/line.). Plus, I will want it to get me to my next emtb riding destination (fun) for as long as the charging cycles can yield! ⚡💵💰💳
 
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Neeko DeVinchi

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Dec 31, 2020
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It would be nice if Bafang implemented a range extender adding 200-250w.
yes, third party range extenders can be used if you choose to go with a third party battery.
But considering that this is the same Bafang who were the first to truly implement the "plug-n-play" concept within their ebike systems, one could say that they've missed a trick.
Screenshot_20231117_150302_Gallery.jpg

I mean, just look at it. You can't convince me that others aren't thinking the same thing😅
 

TCFlowClyde

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It would be nice if Bafang implemented a range extender adding 200-250w.
yes, third party range extenders can be used if you choose to go with a third party battery.
But considering that this is the same Bafang who were the first to truly implement the "plug-n-play" concept within their ebike systems, one could say that they've missed a trick.
View attachment 129233
I mean, just look at it. You can't convince me that others aren't thinking the same thing😅
Or SZZS has their battery maker fabricate a nice extender as standard optional purchase upgrade.

But I suspect that's why they offered the big 720Wh instead. Cheaper to make bigger than small 410Wh plus extender. That being said, I'd take an extender (for camping trips) and don't want to make one, or be smart enough to make the more challenging extender to discharge evenly/safely. (As we learned from Mike our group electrical engineer...it's more complex😁).

If I had a smaller battery, 410Wh, I definitely feel I would need an extender regularly.💯
 
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mike_kelly

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It would be nice if Bafang implemented a range extender adding 200-250w.
yes, third party range extenders can be used if you choose to go with a third party battery.
But considering that this is the same Bafang who were the first to truly implement the "plug-n-play" concept within their ebike systems, one could say that they've missed a trick.

I mean, just look at it. You can't convince me that others aren't thinking the same thing😅
It does seem odd that a company that is said to own the ebike motor market puts so little resources into developing their high end market. Sure they make most of their money off low end motors at very high volume but they can't invest more in our market?

Still we are a DIY group right?

EBwithCable.jpg
 

TCFlowClyde

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It does seem odd that a company that is said to own the ebike motor market puts so little resources into developing their high end market. Sure they make most of their money off low end motors at very high volume but they can't invest more in our market?

Still we are a DIY group right?

View attachment 129238
Nicely done! 👊
DIY E-mtb group yes, but not necessarily a DIY E-mtb battery group. But I'd give it a shot if there was a easy-to-use tutorial in order to convert a pre-fabed battery extender. Like yours.😋
 

mike_kelly

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Your wish is my command...

Ragnarok2.JPG
 

TCFlowClyde

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Your wish is my command...

View attachment 129248
I guess I missed the memo here. You did this in July then? It must have been too damn hot then in order to take in new info. 🫣
 

TCFlowClyde

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That I can believe!!!! I would not survive 110deg for a month.
Ok just read the thread (scanned it really). I was out of town emtbing in Cortez, Colorado--Phil's World those few weeks.

But I still hope for a YouTube video battery extender build for "the NOT smart people"....

Maybe a future Neeko vid?🙏
 

TCFlowClyde

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Also, Neeko...maybe a hack to update the BMS firmware for 10-15% battery reserve....it's almost X-Mas season. Another great present to the M820 Bafangers.🎁🎄🎅
 

Phatty

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Feb 18, 2021
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Utah
Just in case if anyone was interested in the performance of the Bafang M820 system👍🏿
@Neeko DeVinchi
Yes, my motor is just as loud. every time I jump back on the m600 with silent gear I realize just how loud the m820 is. I dont think thats go pro amplifying the noise, its just that loud.
Was that a 60-65 RPM on your cadence? Interesting to me as I find that motor seems to do so much better up around 75-90. I will downshift to spin at that cadence vs letting the motor work that much harder. I run a 34t chainring vs your 32t so maybe thats the difference. Good video, ill have to break out the go pro and film some stuff.
 

Neeko DeVinchi

E*POWAH Elite World Champion
Dec 31, 2020
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@Neeko DeVinchi
Yes, my motor is just as loud. every time I jump back on the m600 with silent gear I realize just how loud the m820 is. I dont think thats go pro amplifying the noise, its just that loud.
Was that a 60-65 RPM on your cadence? Interesting to me as I find that motor seems to do so much better up around 75-90. I will downshift to spin at that cadence vs letting the motor work that much harder. I run a 34t chainring vs your 32t so maybe thats the difference. Good video, ill have to break out the go pro and film some stuff.
I had the same thought in terms of upping my cadence. I did reattempt a steeper climb a couple of days ago. Until,
Screenshot_20231120_164953_Gallery.jpg

I snapped the friggin chain😅.
Screenshot_20231120_165000_Gallery.jpg

Yeah, 75nm of torque. I should have seen it coming.
To add insult to injury, I forgot my multi tool with a spare quick link and chain breaker.
Screenshot_20231120_164956_Gallery.jpg

Oh well!!😁
As for the noise, yes. It's audible. And I wouldn't sugar-coat my opinion of the noise from the M820 with the classic"you'll get use to it" response. But i wouldn't mind getting another copy of the M820 to mess around with and cracking one open. In fact, i have no choice as I've literally made arrangements for two further frames which use the M820 to be sent my way (thankfully, these frames have XL frame sizes). By the time I've cracked one open, I'm sure I'll fathom how to get the M820 whisper quiet. So I'll gladly share my experiences👍🏿
 

Phatty

Member
Feb 18, 2021
38
76
Utah
The problem is that going below 20% is going to reduce the number of charge cycles over the lifetime.
In the grand scheme of things, batteries are cheap. $500 to build one.
Like everything else on bikes batteries are a wearable/changeable component to me that wears out over time. Its far more important to me to get the distance/vert assistance I need during a ride than to get an extra couple ride 3-4 years from now. If I lose 10-20 charges by getting full power down to 10% on a few rides, I would take that trade off.
I also understand though that I am not the normal customer and I will push this bike to the limits and do 40-60 mile rides with 7-10,000 feet of climbing next summer. I need the full battery. It would be nice if it was a controllable thing from the besst tool or the app for the customer who is fine voiding warranty.

IMG_3740.PNG IMG_3741.PNG
 

Neeko DeVinchi

E*POWAH Elite World Champion
Dec 31, 2020
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@Neeko DeVinchi
Yeah low cadence big power is hard on those chains!! Ebikes should have a built in chainbreaker tool. hopefully the walk wasnt too long for you.
I swapped the chain out once I got back. But it was too dark to reattempt the climb that same day.
I may look into those one up edc tools for the CEF50 along with future builds👍🏿
 

mike_kelly

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I swapped the chain out once I got back. But it was too dark to reattempt the climb that same day.
I may look into those one up edc tools for the CEF50 along with future builds👍🏿
12s? Seems like there are quite a few reports of 12s being more prone too breakage than say 11s.
 

TCFlowClyde

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12s? Seems like there are quite a few reports of 12s being more prone too breakage than say 11s.
The only 12 spd that seems e-durable is all Sram eagle. I use the XX1...cause I wanted all black links.😎 The others E-KMC/Shimano XT not so much good luck.
 

TCFlowClyde

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But it seems like 12s is not durable for standard MTB either.
Yes agreed. On my big fattie M620 160 Nm, I have an Sram EX1 that uses a special 9 spd chain for and 8 spd cassette with a trigger pod that shifts only up and down one at a time. I think it's a precursor to the new Transmission wireless?

Anyway, it's time for a lightweight internally geared hub or geared motor, so the mtb community can finally ditch the rear mech for good. 💪

Way better for shifting under load and in higher power modes to avoid the "crunch" and "clanking" sounds when shifting up the gear range.
 

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