M820 Bafang - LIGHTCARBON LCE930 Frame (lightweight)

[Bengy22]

Pretty much agree with the above. A couple of notes though. The 50E’s at 2P are marginal at the levels of 15A. We built such a pack and at the lower cell voltage levels it would voltage sag enough under load to trigger the BMS when used around 350W’s for any length of climb. We built a 40T 2P pack and it out performed the 50E pack even though it was nearly 1Ah less in capacity. We converted the 50E to a 3P pack ( it becomes 30A constant load ) and it has been really really good. It seems way better than the specs under that use.

In all electronics keeping everything cool is key. Wrapping your batteries in foam will only keep the heat building up. Key is to attach the batteries to some form of heat dissipation, what better than a very large surface area that is open to the air. I’m talking about your frame here. Key is to get big areas of surface contact to the frame over a large area and no, small mounting bolts won’t do that unless you build in pads that are then compressed against the frame by the bolts.

With all this sort of thing it’s all about monitoring the situation. You are effectively leading the way and if you use low power levels at first, building up to higher levels if the temps are holding down, then it maybe good for us all to be able to go down the 1P route in these lightweights.

A caveat here, do make sure at some stage you test a full power run over a length of time. You only need to lend your bike to a less able rider who will increase the power levels and you may find your normal battery temp will be far exceeded.

Good point about the true capacity on the cells when they are pushed to their max. With that in mind it actually might be better for brbr to go with something like a P45B which although on paper is 500mah less actually will from what I've read from mooch match the 50S around the 15a mark while running a lot cooler. Has rating that are 2x what the motor will pull so well within spec. Something to think about!

I clearly did not take into consideration the series connection (first battery build).
The more I'm reading and now I see it will be complicated to have the good amp rating for the series connection. What do you think is the best ? copper / nickel welding seems maybe too difficult for a beginner ? use wide nickel strip ? thicker ?

Yes this is also why its good to have more than 1p, as with 2 you usually will have also two series connections to also share the load (and so on for more series connections) which makes it easier to spec the total connection rating. But once you get into space concerns you run into times where you cannot do that due to the layout needing to fit the bike so it becomes a thought out design on the best way to make your parallel banks to make the best series connections. Well it depends on how powerful your spot welder is, most of the cheaper "handheld" ones cannot take the extra power even which using nickel plated steel to help the copper weld. I wouldn't call it harder for yourself but your welder. If you wanted to stick with nickel make sure (and test because sellers can lie) that you get pure nickel before doing anything! anything that increases the amount of nickel would give it a higher amp rating, but going thicker can cause you to run into welder issues like with copper. .2mm is usually when the cheaper ones start to struggle as well, which is why I suggested doubling up on say 15x.15mm which is the practice of just welding another strip on top of the first already welded one. I encourage you too look more into the "nickel copper sandwich" and the spot welder you have / will buy so you can decide yourself exactly what route you want to go.

And because it was brought up maybe look into a 14s bluetooth bms, usually a large portion of bluetooth models actually allows the user to change the amount of cells in the app, so you could configure it to 12s and get the benefits of knowing exactly what's going on in the pack and cell temp.

 

[Waynemarlow]

Yes this is also why its good to have more than 1p, as with 2 you usually will have also two series connections to also share the load (and so on for more series connections) which makes it easier to spec the total connection rating.

Yep everything we looked at suggested 1P was really only good for an extender battery in conjunction with the main pack. I think Spec SL's will run on only the extender pack but I can't confirm that. I would suspect at realtively low W's perhaps ?

To weld 0.2mm nickel you have to have a welder that will apply a lot of pressure on the mating surfaces. The hand held welders just will not do that. I spent more than a few nights trying to sort the riddle of why a friends battery was failing, the weld looked really good on the surface but once you started to lever the nickel a bit ( plastic lever please gents ) the welds simply fell off the battery. Really difficult and time consuming to solve. He had used a hand welder.

We ( as a group of 6 riders ) spent a lot of years and 10's K's of mileage in relatively hilly territory on the TSDZ2 engine, which sort of equates to the New M820 engine. From experience as much as you think you will use low power levels, inevitably the speed builds up, the climbs build up and the experience of enjoying the uphills as much as the downhills, builds up to such an extent that 200W's to 350 W's minimum sort of becomes the norm. At that stage the 1P batteries sort of become irrelavent.

 

[haydz26]

hi there, new member looking at building up an m820 with lc frame , i have a few questions for people that have completed there builds and done a bit of riding on there bikes

how does the performance and power delivery of these motors compare to the factory light ebikes like the trek fuel or specialized levo sl? and how would it compare to the full power bosch or brose motors etc ?
i currently have a marin hawk hill with tsdz2 that weighs around 20kg has anyone also ridden a similar tsdz build that could compare the performance? mainly wondering about climbing ability as i often ride some steep stuff and looking for something with plenty of uphill power

weight wise is it fairly easy to get down to around 18-19kg without spending heaps on high end lightweight components?

cheers

 

[clix]

no idea, apparently they received the bolts and shipping should happen very soon, it's possible that it has already been shipped, so not sure that they will have the chain guides

I asked Wendy about it. She said, that if testing/fitment will be OK, I will also receive a chain guide.
My frame should be painted by the end of the month.

@brbr any updates about your frame?

I can't wait to put whole bike together! Currently, I have everything, apart from frame, battery and dropper post. Will try if my current 210mm will fit, before I order new one, otherwise I will have to go with 180mm one. When I receive the frame, I will create a new build thread, to showcase build, and also the frame quality, alignment, fit and finish..

Regarding the battery, who knows when...
Maybe I will have to use it as a normal bike for a while...

 

[clix]

hi there, new member looking at building up an m820 with lc frame , i have a few questions for people that have completed there builds and done a bit of riding on there bikes

how does the performance and power delivery of these motors compare to the factory light ebikes like the trek fuel or specialized levo sl? and how would it compare to the full power bosch or brose motors etc ?
i currently have a marin hawk hill with tsdz2 that weighs around 20kg has anyone also ridden a similar tsdz build that could compare the performance? mainly wondering about climbing ability as i often ride some steep stuff and looking for something with plenty of uphill power

weight wise is it fairly easy to get down to around 18-19kg without spending heaps on high end lightweight components?

cheers

Few objective links of the tests from motor in the Forestal, witch is probably very very similar to the M820 one:

Light E-Bike-Motor: Forestal F60-S1 (Bafang) im Test

Die kleine Schmiede Forestal aus Andorra hat gemeinsam mit Bafang einen eigenen Antrieb für leichte E-Bikes entwickelt. Der kompakte Bafang-Motor hat uns mit reichlich Power überrascht. Ein Test in Labor und Praxis.

www.bike-magazin.de

Fazua, TQ, Specialized & Co.: 5 leichte E-Bike-Motoren im Test

Leicht, leise, unauffällig: So wollen Light-E-Mountainbikes den Markt erobern. Wir haben die 5 leichtesten E-Bike Motoren in Labor und Praxis getestet.

www.bike-magazin.de

E-MTB Test-Duell Light-Enduros 2023: Forestal Siryon Neon vs. Transalpes E1 Enduro

Geht das Konzept Light E-Bikes auch in der Enduro-Klasse auf? Wir wollen es wissen und schicken wir das Forestal Siryon und Transalpes E1 Enduro ins Duell.

www.bike-magazin.de

You can use google translate, to translate the pages.

 

[brbr]

I asked Wendy about it. She said, that if testing/fitment will be OK, I will also receive a chain guide.
My frame should be painted by the end of the month.

@brbr any updates about your frame?

I can't wait to put whole bike together! Currently, I have everything, apart from frame, battery and dropper post. Will try if my current 210mm will fit, before I order new one, otherwise I will have to go with 180mm one. When I receive the frame, I will create a new build thread, to showcase build, and also the frame quality, alignment, fit and finish..

Regarding the battery, who knows when...
Maybe I will have to use it as a normal bike for a while...

I have a DHL tracking number! But I think I won’t have the tracking until the frame reached EU. So I have no idea when it will be here.
I guess no chain guide for me, but I’m not really interested !
For the battery, I’m waiting for the bafang, which should be in stock by the 8th (I’m expecting sole delay…). Otherwise I bought the cells to do a very small one, I’ll see if I build it anyway!
For the parts, I have everything, very cheap dropper, I’ll upgrade it later.
I’m still hesitating if I should paint the frame or not, I don’t want to spend several hours sanding the frame I’ll see if it’s clean enough to paint it directly

 

[brbr]

Few objective links of the tests from motor in the Forestal, witch is probably very very similar to the M820 one:

Light E-Bike-Motor: Forestal F60-S1 (Bafang) im Test

Die kleine Schmiede Forestal aus Andorra hat gemeinsam mit Bafang einen eigenen Antrieb für leichte E-Bikes entwickelt. Der kompakte Bafang-Motor hat uns mit reichlich Power überrascht. Ein Test in Labor und Praxis.

www.bike-magazin.de

Fazua, TQ, Specialized & Co.: 5 leichte E-Bike-Motoren im Test

Leicht, leise, unauffällig: So wollen Light-E-Mountainbikes den Markt erobern. Wir haben die 5 leichtesten E-Bike Motoren in Labor und Praxis getestet.

www.bike-magazin.de

E-MTB Test-Duell Light-Enduros 2023: Forestal Siryon Neon vs. Transalpes E1 Enduro

Geht das Konzept Light E-Bikes auch in der Enduro-Klasse auf? Wir wollen es wissen und schicken wir das Forestal Siryon und Transalpes E1 Enduro ins Duell.

www.bike-magazin.de

View attachment 120164


You can use google translate, to translate the pages.

I guess they is to keep it under 90rpm!

 

[Lussy]

Hi guys, “long time lister, first time caller”
I have been reading this and the CF50 thread for 6 months. So much information.
I have finished my build, I was aiming for as light as possible without trading on downhill performance. 170/150 suspension.
Final weight at 17.5 kg with 360Wh battery (homemade). Pretty much Chinese carbon everywhere, except cranks which I haven’t found yet….
Cost $3300usd.
Sorry for the crap pics, will post some better ones and a breakdown of components cost / weight for anyone interested

 

[Lussy]

Only one problem, the speed sensor plugs don’t match with with a 8pin connector on the motor and a 4 pin on the sensor wire. Motor runs for a couple secs then trips on speed sensor fault as it isn’t connected.
Does anyone know if this can be overridden or the control mode changed with the besst tool, while I wait for the correct sensor to arrive?

 

[brbr]

Hi guys, “long time lister, first time caller”
I have been reading this and the CF50 thread for 6 months. So much information.
I have finished my build, I was aiming for as light as possible without trading on downhill performance. 170/150 suspension.
Final weight at 17.5 kg with 360Wh battery (homemade). Pretty much Chinese carbon everywhere, except cranks which I haven’t found yet….
Cost $3300usd.
Sorry for the crap pics, will post some better ones and a breakdown of components cost / weight for anyone interested
View attachment 120567 View attachment 120568

very nice! 17.5Kg is amazingly light, good job!

 

[Peter A]

Hi guys, “long time lister, first time caller”
I have been reading this and the CF50 thread for 6 months. So much information.
I have finished my build, I was aiming for as light as possible without trading on downhill performance. 170/150 suspension.
Final weight at 17.5 kg with 360Wh battery (homemade). Pretty much Chinese carbon everywhere, except cranks which I haven’t found yet….
Cost $3300usd.
Sorry for the crap pics, will post some better ones and a breakdown of components cost / weight for anyone interested

Nice one, I'm very interested to see how the bars and wheels hold up on rougher descents and how it handles. Are they both from LC?

 

[Lussy]

Will let you know about the wheels and bars. The bars are from LC, the wheels from aliexpress

NZ$661.38 28％ Off | 29er Carbon MTB Wheelset Ultralight Ratchet System UCI Approved 6 Bolt / Center Lock Boost 15x110 12x148 Tubeless MTB Wheels 29

https://a.aliexpress.com/_mNFnbtU

 

[savas]

Show us a picture of the battery or the way you have mounted it in the frame.Did you make your own case? Weight of the battery?

 

[brbr]

Quite impressed of the weight with these tires as well! I guess the choice for carbon wheelset and DIY battery really helped!

 

[Lussy]

Show us a picture of the battery or the way you have mounted it in the frame.Did you make your own case? Weight of the battery?

Show us a picture of the battery or the way you have mounted it in the frame.Did you make your own case? Weight of the battery?

It’s a bit agricultural for now, but holding in very sold. I have used a carbon / plastic plate on the bottom of the battery with tapped screw holes aligning with the frame holes. I am making a 3d printed version to allow a nut to be used instead as I dont trust the plastic threaded tapping

 

[Lussy]

Quite impressed of the weighth these tires as well! I guess the choice for carbon wheelset and DIY battery really helped!

Yes the tires are relatively heavy. The areas where weight could be reduced are the tires, cranks, bafang chainring spider, dropper, and perhaps titanium bolts? probably another ~ 1kg

The standard bafang chainring, bolts and spider are very heavy (all steel) - a bit strange given the efforts to save weight in the motor.

Breakdown of cost and weight below, I weighed all components and the overall bike after, matched pretty well!!

 

[Lussy]

Some motor internal pics, thought I had a motor connection issues to resolve, but was my battery!
A lot of grease in the controller which is not ideal?

 

[Lussy]

Overall very happy with the frame, the only issues I have with the frame is mounting the motor. The bolt nearest the battery has some bushings to go in which are practically impossible to install, anyone found an way?. It is a very tight fit with the motor housing and they won’t sit in without being held. I have left the bushings out for now.

Also the brake side rear axle mount wasn’t painted properly , perhaps there was supposed to be some sort mount, but wasn’t provided and the rear axle is the right length as fitted.

 

[brbr]

Yes the tires are relatively heavy. The areas where weight could be reduced are the tires, cranks, bafang chainring spider, dropper, and perhaps titanium bolts? probably another ~ 1kg

The standard bafang chainring, bolts and spider are very heavy (all steel) - a bit strange given the efforts to save weight in the motor.

Breakdown of cost and weight below, I weighed all components and the overall bike after, matched pretty well!! View attachment 120606

Very nice build, thanks for the details!
Can’t wait to receive mine, which will be heavier for sure, bafang battery, alloy wheelset, coil shock, …

 

[thaeber]

Overall very happy with the frame, the only issues I have with the frame is mounting the motor. The bolt nearest the battery has some bushings to go in which are practically impossible to install, anyone found an way?. It is a very tight fit with the motor housing and they won’t sit in without being held. I have left the bushings out for now.

Also the brake side rear axle mount wasn’t painted properly , perhaps there was supposed to be some sort mount, but wasn’t provided and the rear axle is the right length as fitted.
View attachment 120610 View attachment 120611

Are You happy with the brakes? Did You ever test them?

 

[forsa355]

Yes the tires are relatively heavy. The areas where weight could be reduced are the tires, cranks, bafang chainring spider, dropper, and perhaps titanium bolts? probably another ~ 1kg

The standard bafang chainring, bolts and spider are very heavy (all steel) - a bit strange given the efforts to save weight in the motor.

Breakdown of cost and weight below, I weighed all components and the overall bike after, matched pretty well!! View attachment 120606

very similar to my upcoming cheapo CEF50 build. Used suspension plus lots of Aliexpress stuff, including the same brakes as you. Unfortunately my CEF50 frame, motor and battery are sitting on a parked ship held up by a Canadian port workers strike :-(
Do you have any pictures of the battery you built? What BMS did you use?

 

[dvng]

Anyone wishing to try overstroking the shock? I am curious to know if it is workable on this frame.

 

[spokémon]

The standard bafang chainring, bolts and spider are very heavy (all steel) - a bit strange given the efforts to save weight in the motor.

Chainring - Dakas 126g Does this include the oem spider?

 

[Lussy]

very similar to my upcoming cheapo CEF50 build. Used suspension plus lots of Aliexpress stuff, including the same brakes as you. Unfortunately my CEF50 frame, motor and battery are sitting on a parked ship held up by a Canadian port workers strike :-(
Do you have any pictures of the battery you built? What BMS did you use?

Sorry, no pics of the battery, BMS below, it’s a smart BMS with Bluetooth to show the cell voltage etc

 

[Lussy]

Chainring - Dakas 126g Does this include the oem spider?

126g grams is the chainring only, the spider is very, very, heavy, around 300g from memory.

 

[Lussy]

Are You happy with the brakes? Did You ever test them?

The brakes seem to have pretty good stopping power and well made. Will see how the last!!

 

[spokémon]

126g grams is the chainring only, the spider is very, very, heavy, around 300g from memory.

300g wow that is substantial!
Is the chainring alloy?

Also the brake side rear axle mount wasn’t painted properly , perhaps there was supposed to be some sort mount, but wasn’t provided and the rear axle is the right length as fitted.

This is a very easy fix. Black matt spray can from auto shop. Hardest part is taping up to prevent overspray.

 

[Lussy]

300g wow that is substantial!
Is the chainring alloy?



This is a very easy fix. Black matt spray can from auto shop. Hardest part is taping up to prevent overspray.

Pretty sure the supplied Chianring is steel. I was thinking the same with the spray can to fix… just a bit annoying to need to do it

 

[savas]

on the motor label i see 60kmh.Is that true? Did you try it and what power does it use if your are riding with 60kmh?

 

[Lussy]

Sorry, not sure about the speed as I haven’t been able to get it running for more than a couple seconds before the speed sensor trip stops the motor. The speed sensor connectors don’t match. Should have it going in a few days though…