That would be great. Otherwise, we would have to bodge something up.
M820 Bafang - LIGHTCARBON LCE930 Frame (lightweight)
- Thread starter mike_kelly
- Start date
i've been reading here silently for a while now. thank you all for all the information. i'm wondering if a size large is right for me at 184 cm height.
This would be my first e-bike but by far not my first self-built bike.
Actually, the project should only start slowly next year, but many components are already in delivery.
I still don't understand the different voltages of the motors and the corresponding batteries etc.. What is the standard version now? but I'll take my time with the order anyway.
The fact that the chain guide is still being discussed makes me want to wait even longer.
This would be my first e-bike but by far not my first self-built bike.
Actually, the project should only start slowly next year, but many components are already in delivery.
I still don't understand the different voltages of the motors and the corresponding batteries etc.. What is the standard version now? but I'll take my time with the order anyway.
The fact that the chain guide is still being discussed makes me want to wait even longer.
I've ordered a size L and I'm 185, I'll tell you if it's too short...
Regarding the motors, if you don't want to go DIY for the batteries, you have 2 choices, 36V bafang 360Wh or 43v Bafang 430Wh. the 43V is not available until mid August, so it should be OK for you I guess! The 36v is also a bit lighter, in theory only 4 cells less, so 4x70gr + wiring, so around 300gr lighter.
Regarding the voltages difference, as discussed in the CEF50 thread, I do not think the internal hardware is different, so no real big deal.
FYI, I am 183cm and I also ordered L.
6/7 weeks ago and already delivered?! It's a size M ?
The custom paint is amazing!
You already have the motor / battery ?
No, it's not delivered, Jim sent me a picture of it finished. Still waiting for delivery. The motor/ battery is still not ready,was told about 15 days but not sure
you went for 43V or 36V ? Where did you ordered ? The 43V btf014 should not be ready before 8 of August (according to my seller)
Very nice looking paint job. How much extra was it? 200€?
As far as I know, you need only 8mm x 22.2mm shock hardware. Considering, you have marzocchi shock, I would probably go with the fox option.
. The paint was crystal sliver and cost $180.Hej, do you maybe know, if they will put those holes for the chain guide also in our frames, or only on the future frames?
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
Waynemarlow
E*POWAH Master
Threw my chain guide away as it was creating problems with sucking in mud and sticks on my M600, fitted a narrow wide front 104 ring and never had a derailment since.
Guys, I need your thoughts about this: I’m building my battery pack: 12s1p, while I wait for the official Bafang battery.
Do you think I should try to install it internally or I install it quick and easy using an external bag on the frame?
1- Internally
Pros: better gravity center / better look
Cons: I have to build a support to install ir in the frame / if it burns, it burns all the bike
2- externally
Pros: easy to install / I can do any form factor I want / risk of fire reduced
Cons: wires going in the frame, less good looking, bad center of gravity
The whole battery pack will be around 1kg, and it should be a temporary solution for 1 month or 2 months
Do you think I should try to install it internally or I install it quick and easy using an external bag on the frame?
1- Internally
Pros: better gravity center / better look
Cons: I have to build a support to install ir in the frame / if it burns, it burns all the bike
2- externally
Pros: easy to install / I can do any form factor I want / risk of fire reduced
Cons: wires going in the frame, less good looking, bad center of gravity
The whole battery pack will be around 1kg, and it should be a temporary solution for 1 month or 2 months
Goff
Member
Internal, if it burns the frame is destroyed either way.
I wrap mind in carbon with Aluminium mounting points, it’s robust probably stronger than a manufactured battery.
6 cells long should be close to the mounting holes, use aluminium flat bar resined to the case, drill and tap holes to suit the frame mounting.
I am starting my battery build soon so will post some photos
I wrap mind in carbon with Aluminium mounting points, it’s robust probably stronger than a manufactured battery.
6 cells long should be close to the mounting holes, use aluminium flat bar resined to the case, drill and tap holes to suit the frame mounting.
I am starting my battery build soon so will post some photos
I should have some spare carbon plates, I need to check that!
How do you attach the cells to the carbon plate?
Waynemarlow
E*POWAH Master
Be careful on your choice of cell, you will need probably a 30A minimum capable cell ( 40A would be better ) to handle a 500W loading. At lower cell voltages you may run the risk of the BMS shutting down the battery early if you under estimate this.
Waynemarlow
E*POWAH Master
Can I ask why carbon plates, it can be highly conductive whereas fibreglass is not and 1/5th the cost.
I chose samsung 50s, they should be in stock in 10 days. 5000mAh, 35A rating
Waynemarlow
E*POWAH Master
You may want to check but the 50S we used were only 20A continuous, looking on line some of the dealers are quoting 25A. There are lots of versions though so do check to see what you have.
In the smaller 2P packs we used the 40T version, really good cells and handled 600W’s right to the full discharge of the pack. We found that sometimes it’s better to take a slightly smaller capacity cell but higher C rating for EBikes, the motors draw off can momentarily exceed the cells output and the voltages drop enough to trigger the low voltage on the BMS.
In the smaller 2P packs we used the 40T version, really good cells and handled 600W’s right to the full discharge of the pack. We found that sometimes it’s better to take a slightly smaller capacity cell but higher C rating for EBikes, the motors draw off can momentarily exceed the cells output and the voltages drop enough to trigger the low voltage on the BMS.
they're rated for 35A max, but I do not have the specs for the continuous discharge. The idea is not to climb in turbo mode during 10 km!
I will mainly be in eco, I'll keep the turbo for when I'll have the bafang
Waynemarlow
E*POWAH Master
Yep should be interesting for us as I don’t know of any 1P packs being used other than some of the extender packs which normally are used together with the main pack. Do report how you get on as 1P would make a great bottle extender pack to be used as a get me home pack.
Out of curiosity I looked up a few constant current tests on the 5OS and they seem to run very hot at the power levels we would encounter. You can get temperature sensors on some of the BMS’s and it wouldn’t be a bad idea to include some sort of sensing as the 80degrees mentioned would be enough to melt any heatshrink and possibly be hot enough to affect the frame epoxy.
Out of curiosity I looked up a few constant current tests on the 5OS and they seem to run very hot at the power levels we would encounter. You can get temperature sensors on some of the BMS’s and it wouldn’t be a bad idea to include some sort of sensing as the 80degrees mentioned would be enough to melt any heatshrink and possibly be hot enough to affect the frame epoxy.
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Waynemarlow
E*POWAH Master
Perhaps fit a couple of heat sensitive strips on just to keep track of things.
www.testo.com
Temperature measuring strips with 14 temperature zones | Testo SE | Testo Ltd
Temperature stickers are the most efficient solution for the temperature control of fast moving parts. Get information about them now and find the best products.
www.testo.com
wow, that's scary :/
I'm going to check if the check I choose has a temp sensor!
yeah, there's a temp sensor on the BMS, that's a start ...
Now, it makes me hesitate to put this in the frame, maybe I'll try install it like a range extender instead of the water bottle, so I can use it sa an extender when the "big" battery will arrive.
Now, it makes me hesitate to put this in the frame, maybe I'll try install it like a range extender instead of the water bottle, so I can use it sa an extender when the "big" battery will arrive.
Imo people are getting way too worried about the cell ratings, 50S's are rated officially 25a continuous 35a peak. Unofficially 20a continuous 35a peak due to temps. While I haven't seen any official posts about how much amps the 43v model uses but assuming bafang would want to keep the max wattage comparable to the 36v (they do this with other motors they make) which peaks around 17a we can estimate roughly 14-15a max amps the battery will see. This is well within the spec's of the 50S, and independent testing (mooch) had the cell hit 63c max from a 15a continuous test. Considering on a ebike we usually don't pull max amps for long I don't see any concerns for running a 1p setup other than range. And plus the bms (I hope a bluetooth model) has a temp probe just in case, if bluetooth you can monitor yourself. I personally would maybe look into doing a 2p though with 50E due to the price of 50S in comparison, that way you get more range for almost the same cost but that might not be true where OP lives.
I would go for the in frame mount (the range extender case idea is also good imo), you will have more than enough space with the little amount of cells you will use. Pack the empty space with lots of foam and I see nothing to be concerned about as long as you or the person who makes the pack knows what they are doing and makes sure to spec the series connections for the 15a draw, as common 15x.1mm nickel is not enough, either doubling up on it or copper would be a wise idea. The backpack would be more safe though if you really were worried about a fire, as you should have a battery connection up at the seat so you just quickly unplug and though the backpack far away keeping the bike safe. Not sure why it would be assumed the bike would be a loss if a fire happened
I would go for the in frame mount (the range extender case idea is also good imo), you will have more than enough space with the little amount of cells you will use. Pack the empty space with lots of foam and I see nothing to be concerned about as long as you or the person who makes the pack knows what they are doing and makes sure to spec the series connections for the 15a draw, as common 15x.1mm nickel is not enough, either doubling up on it or copper would be a wise idea. The backpack would be more safe though if you really were worried about a fire, as you should have a battery connection up at the seat so you just quickly unplug and though the backpack far away keeping the bike safe. Not sure why it would be assumed the bike would be a loss if a fire happened
I finally went for 1p instead of 2p because I do not need in the end 2 full size batteries. The price difference was not huge in the end, but I will be able to reuse it as an extender if I can, we'll see.
Regarding the BMS, it was not available (or I did not find it) in bluetooth for 12s.
12S Lifepo4 or Lithium Ion Battery BMS – LLT POWER ELECTRONIC
I haven't used these BMSs, but it looks like they have 12s bluetooth options.
I haven't used these BMSs, but it looks like they have 12s bluetooth options.
Waynemarlow
E*POWAH Master
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.
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.
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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 ?
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