M820 Bafang - LIGHTCARBON LCE930 Frame (lightweight)

Migli54 said:
And it works well? Isn't there a problem with the Cut Off?
Battery 43V Cut off = 40.8V ( 3,4 V / cell)
Battery 36V Cut off = 34V (3.4V / cell)

Intuitively, I'd say that with a 36V you have an operating range that goes from 42V (Full charge) to 40V (Cutoff) and then it cuts off, right?
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You need to have corresponding battery to your motor controller firmware. Firmware can be easily changed, battery not so easy.
Working range for li-ion cells is about 4.2-2.7V with most BMS. So 36V battery would be 27V to 42V.

If you like an extender and don’t want to build your own batteries, go for 36V or 48V. 43V seems to be Bafang specialty and finding an extender might be difficult.
 
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Migli54 said:
And it works well? Isn't there a problem with the Cut Off?
Battery 43V Cut off = 40.8V ( 3,4 V / cell)
Battery 36V Cut off = 34V (3.4V / cell)

Intuitively, I'd say that with a 36V you have an operating range that goes from 42V (Full charge) to 40V (Cutoff) and then it cuts off, right?
Click to expand...
All LION batteries with the M820 will cutoff after 80% used. Nothing to do with the voltage of the battery.
THe M820 comes in three different versions, 36v,43v,48v.
The firmware sets the cut-off for motors designed for different voltage.
 
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You say that the engine behaves exactly the same whether it's powered by a 43V or a 36V battery?

That the cut-off is set to 80% on the batteries is one thing. That the bike operates identically, I doubt it.

What have you experienced on this side?
 
There is no difference. Power is power. A 43v motor is not more "powerful" than a 36v motor. It is a myth.
The higher the voltage the lower the current required for a certain power level. That can allow a manufacturer to create a lighter motor with smaller conductors at the higher voltage. But that is the only difference and it is not clear if Bafang changes the size of the conductors for higher voltage motors. I doubt it.
 
mike_kelly said:
There is no difference. Power is power. A 43v motor is not more "powerful" than a 36v motor. It is a myth.
The higher the voltage the lower the current required for a certain power level. That can allow a manufacturer to create a lighter motor with smaller conductors at the higher voltage. But that is the only difference and it is not clear if Bafang changes the size of the conductors for higher voltage motors. I doubt it.
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Intuitively, I'd say that the nominal voltage and max current are hard-coded in the controller.

So if you take a 43V - 13A firmware -> 560 W
If you power it at 36V, the max current is alway 13A...
So your Pmax will be 36 x 13 = 468 W.
-> You lose 100W of nominal power on your motor... What do you think of this resonance? Wrong?

BESST_PIC.png
 
Migli54 said:
Intuitively, I'd say that the nominal voltage and max current are hard-coded in the controller.

So if you take a 43V - 13A firmware -> 560 W
If you power it at 36V, the max current is alway 13A...
So your Pmax will be 36 x 13 = 468 W.
-> You lose 100W of nominal power on your motor... What do you think of this resonance? Wrong?

View attachment 136745
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Well, this is why the 36V firmwares have higher current than 43 and 48V. So the max power remains the same.
 
Freda said:
Well, this is why the 36V firmwares have higher current than 43 and 48V. So the max power remains the same.
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You mean you're running 43V with a 43V battery and when you plug in the battery extender with 36V nominal you load a new firmware into the motor?
 
Migli54 said:
You mean you're running 43V with a 43V battery and when you plug in the battery extender with 36V nominal you load a new firmware into the motor?
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No, even if that would work in theory, that is too complicated. You need to have same voltage on main battery, extender and firmware. Any one of the three options work.

Bafang have 360Wh 36V battery, if you use that it would be easy to find extender. I don't know if you can buy that via lightcarbon though.
 
360w is 360 w. As noted with 43 it is 8.37 amps and with 36v it is 10amps. So the 43v could have smaller wires that would be lighter, slightly. That would be the advantage of the higher voltages but does Bafang actually change the gauge of the wires in the motors or batteries? For lowest cost I would guess no. But the max current is different for the two motors in question.
 
mike_kelly said:
360w is 360 w. As noted with 43 it is 8.37 amps and with 36v it is 10amps. So the 43v could have smaller wires that would be lighter, slightly. That would be the advantage of the higher voltages but does Bafang actually change the gauge of the wires in the motors or batteries? For lowest cost I would guess no. But the max current is different for the two motors in question.
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Once again... You don't take into account the maximum current programmed in your controller. But I have my answer thanks @Freda
 
You can't program in max current. You can only limit it by clamping it. These are controlled by a pulse train to the speed controller. The motor is going to pull what it pulls at a certain assist setting based on the resistance of the windings. The only thing the controller is programmed to do is limit the assist level after the voltage drops to a trigger level.
 
If anyone is interested in buying an LCE930 in the USA, I'm considering selling mine.

For Sale (BIKE) - 2023 LightCarbon LCE930 L: 6000 USD

Bike / Product Year: 2023 Manufacturer: LightCarbon Model: LCE930 Size L Asking Price: 6,000 USD Location Los Angeles, CA Description 2023 LightCarbon LCE930 43v version. I've put 44 miles on the bike. Weighs in at 17.5kg's ready to ride. This bike has been a blast, way lighter and more nimble...
www.emtbforums.com www.emtbforums.com
 
Had a shake out ride a week or so ago (snow came back since) but we went out and did 10km and where I would be stopping and waiting many times and cringing about my bad boyfriend trail choices, this time any time I looked over my shoulder she was right there! Going to be a great summer with this in the stable.

Short clip of her going up a steep rooty climb. This is the bottom of a G out that is much steeper than it looks...and she just charges up it.
photos.app.goo.gl

New video · Saturday, Mar 16, 2024 🎬

Tap to view!
photos.app.goo.gl photos.app.goo.gl
 
cwoodffr said:
Had a shake out ride a week or so ago (snow came back since) but we went out and did 10km and where I would be stopping and waiting many times and cringing about my bad boyfriend trail choices, this time any time I looked over my shoulder she was right there! Going to be a great summer with this in the stable.

Short clip of her going up a steep rooty climb. This is the bottom of a G out that is much steeper than it looks...and she just charges up it.
photos.app.goo.gl

New video · Saturday, Mar 16, 2024 🎬

Tap to view!
photos.app.goo.gl photos.app.goo.gl
Click to expand...
Nice! I wish I could talk my wife into doing trails like that. She went over the bars once and that was the end of trail riding.
 
sandnap said:
Nice! I wish I could talk my wife into doing trails like that. She went over the bars once and that was the end of trail riding.
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I hear ya.....I have to find the balance to keep the fear down....and she has had a few OTB's but powers on. She is an extreme sport gal from a lifetime of kiteboarding and wakeboarding....but some bad on water accidents has made her more cautious. At 56 and the combo of techy plus hard exertion at the same time was a blocker so this should REALLY help.
 
mike_kelly said:
You can't program in max current. You can only limit it by clamping it. These are controlled by a pulse train to the speed controller. The motor is going to pull what it pulls at a certain assist setting based on the resistance of the windings. The only thing the controller is programmed to do is limit the assist level after the voltage drops to a trigger level.
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Ho my god
 
Wow that was not a great review! Seems like they needed a larger size. My experience with the bafang is quite the opposite to what they reported, i find I have to spin higher rpm's to get the most out of it, but also I haven't made any changes or plugged in the besst tool yet. How do others feel? I'm 80kg and my wife is around 60 kg and for her, she can pedal at a lower cadence and it works, more than I can. I assume it's the weight it's trying to get up the hill? It seems the combo of long stem and shorter frame for their test gave them overall not the most confidence inspiring feeling, Im loving the mullet set up, we're running probably a more aggressive set up with a coil shock, short stem, 170mm fork and smaller rear wheel and 155mm cranks, it's been super fun and we ride a lot of steep tech trails up in the PNW. I've even enjoyed the longer chainstay with more stack height on mine, it's a nice balance. I haven't ridden a lot of other bikes though, I do have some friends with relays I need to check out but overall we've both been really enjoying the light carbon. Especially how it rides much closer to our regular enduro bikes on the downs.
 
For them the pick Power of the motor is not enough. They prefer motor with lot of torque. And if I understood they find the autonomy of battery is not good. They don’t like the security at 20%
 
hello
I am building this frame with the Bafang M820 motor.

The motor came with a 34-tooth chainring, but I think it will be too big for me, currently on my MTB I have a 32-tooth chainring.

What dish do you have?
greetings
 
32 and 11/52 with 29", 11/50 with 27.5. I would used less if i could, 28 and reduced K7 rear (less cheaper and more light) , but with 104BCD spider it's impossible to mount less than 32
 
patdam said:
32 and 11/52 with 29", 11/50 with 27.5. I would used less if i could, 28 and reduced K7 rear (less cheaper and more light) , but with 104BCD spider it's impossible to mount less than 32
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hello

And where can I buy that 32t chainring.

I'm looking everywhere and I don't see anything.

I only see on the one hand a spider (which I can't know if it is compatible with this engine) and on the other hand what is the toothed plate.
To say that the engine came to me with a one-piece plate.
greetings
 
patdam said:
32 and 11/52 with 29", 11/50 with 27.5. I would used less if i could, 28 and reduced K7 rear (less cheaper and more light) , but with 104BCD spider it's impossible to mount less than 32
Click to expand...
I have not tried with this spider, but on normal 104bcd crankset a 30T chainring is minimum. It has threads in the chainring instead of using bolt with counterpart, to get it to fit.
 
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